JP2018113556A - Wavelength multiplex optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both enhanced economical efficiency and securing of high reliability.SOLUTION: Each of slave station devices (#1 to N#) of a wavelength multiplex optical communication system 1, includes: a slave station transmission part that transmits a slave transmission signal beam as a signal beam of a first wavelength group in an assigned wavelength group; a slave station reception part that receives a slave station reception signal beam as the signal beam of a second wavelength group in the wavelength group; a group multiplexing/demultiplexing unit 131 that extracts a part of a master station transmission signal beam and inputs the slave transmission signal beam to a transmission path; and switching parts 113 and 123 that provide the slave station reception signal beam to the slave reception part on the basis of a switching instruction signal outputted by a switch control part 132, and switch a transmission direction where the slave transmission signal beam inputted to transmission paths 61 and 62 is transmitted in the transmission pass. A wavelength included in the wavelength group assigned to the slave station device is not overlapped, and the wavelength included in the first wavelength group and the wavelength included in the second wavelength are not overlapped each other in each slave station device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength division multiplexing optical communication system in which a master station apparatus and a plurality of slave station apparatuses are connected by a single-core bidirectional transmission path through which signal light is transmitted bidirectionally.

  In recent years, in areas where base stations are crowded such as in urban areas, a control / baseband unit (BBU) and a radio unit (RRH: Remote Radio) are used in order to respond to high-speed and large-capacity communication via mobile networks. A mobile front-haul (MFH) in which the heads are separated from each other is attracting attention.

  MFH connects one BBU and multiple RRHs by radio or optical fiber and aggregates BBUs to promote space saving and low power consumption at each base station. It is possible to reduce CAPEX (Capital Expenditure) and operating cost (OPEX: Operating Expense). On the other hand, since mobile users use mobile traffic in their daily lives, they are demanding that the incommunicable period does not continue due to a failure or the like and that the network has high reliability. For this reason, it is important for the communication carrier to simultaneously improve the economics of the network and ensure high reliability.

  In order to improve the economics of the network, wavelength division multiplexing (WDM) that enables large-capacity transmission with a single optical fiber is used, and signal light is transmitted bidirectionally with a single optical fiber. A system that employs single-core bidirectional transmission is proposed (see, for example, Patent Document 1 and Patent Document 2). However, the systems described in Patent Document 1 and Patent Document 2 are used because they employ a configuration in which a detour route of a single optical fiber as a transmission path used cannot be secured. There is a problem that traffic is completely interrupted when an abnormality occurs in the transmission path.

  In order to ensure high reliability of the network, an optical communication system having a single-core bidirectional transmission path constructed in a redundant configuration so that traffic is not completely interrupted even when an abnormality occurs in the transmission path. Necessary (see, for example, Patent Document 3). The system described in Patent Document 3 includes a plurality of optical transmitters and a plurality of optical receivers, each of which is connected to a switch device for switching a transmission path, and when there is a fault in the transmission path, the plurality of optical transmitters And a plurality of optical receivers are connected via a transmission line (optical fiber) switched by a switch device, thereby performing communication through a single-core bidirectional transmission line.

Japanese Patent No. 4602900 Japanese Patent No. 4852260 Japanese Patent No. 4035714 (for example, FIGS. 14 and 15, paragraphs 0177 to 0184)

  However, in the system described in Patent Document 3, switch devices are provided in both terminal stations connected by optical fibers, and the number of switch devices corresponding to the number of wavelengths of signal light to be transmitted is required. Therefore, there is a problem that the network cost becomes high. In other words, in the case of adopting the redundant configuration disclosed in Patent Document 3 in single-core bidirectional transmission, the basic configuration is a 1: 1 redundant configuration having a switching function in both terminal stations connected by optical fibers. Therefore, when a ring network or a chain network is constructed, the number of switching devices corresponding to the number of wavelengths of signal light to be transmitted is required, and there is a problem that the network cost becomes high. Here, the 1: 1 redundant configuration is composed of an operation transmission line and a preparation transmission line, and in the absence of a failure, a service signal is not transmitted to the preparation transmission line (in parallel transmission). A configuration in which a service signal is transmitted to a transmission line in a preparation system when there is a failure.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a wavelength division multiplexing optical communication system capable of achieving both improvement in economy and ensuring of high reliability.

  A wavelength division multiplexing optical communication system according to an aspect of the present invention includes a master station device, a plurality of slave station devices, and a ring type that returns from the master station device to the master station device via the slave station devices. A one-core bidirectional transmission path that connects a master station device and the plurality of slave station devices and transmits wavelength multiplexed signal light in a first direction and a second direction that is opposite to the first direction; And each of the plurality of slave station devices transmits a slave station transmission signal light which is a signal light of a first wavelength group among the wavelength groups previously assigned to each of the plurality of slave station devices. A station transmitter, a slave station receiver that receives a slave station received signal light that is signal light of the second wavelength group of the wavelength group, and a master station transmission that is transmitted from the master station device to the transmission path Of the signal light, a part of the first master station transmission signal light transmitted in the first direction and the second light is transmitted in the second direction. A part of the two master station transmission signal lights is demultiplexed and extracted as the first reception signal light and the second reception signal light, and the slave station transmission signal light is input to the transmission path. A wave control unit, a switching control unit that outputs a switching instruction signal based on levels of the first master station transmission signal light and the second master station transmission signal light, and the first instruction signal based on the switching instruction signal. Either the received signal light or the second received signal light is provided to the slave station receiving unit as the slave station received signal light, and the slave station is input to the transmission path based on the switching instruction signal A switching unit that switches a transmission direction in which transmission signal light is transmitted through the transmission path to either the first direction or the second direction, and the wavelength allocated in advance to the plurality of slave station devices The plurality of slave station devices so that the wavelengths included in the group do not overlap each other The plurality of slave station devices are configured such that the wavelengths included in the first wavelength group and the wavelengths included in the second wavelength group do not overlap each other in each of the plurality of slave station devices. Is.

  In addition, a wavelength division multiplexing optical communication system according to another aspect of the present invention includes a master station apparatus, a plurality of slave station apparatuses, the master station apparatus and the plurality of slave station apparatuses connected in a chain type, and wavelength multiplexing A one-way bidirectional first transmission path in which signal light is transmitted from the master station device to the plurality of slave station devices in a downlink direction and an uplink direction opposite to the downlink direction; and the master station device; A single-core bidirectional second transmission in which the plurality of slave station devices are connected in a chain form, and wavelength division multiplexed signal light is transmitted from the master station device to the plurality of slave station devices in the downlink and uplink directions. Each of the plurality of slave station devices transmits a slave station transmission signal light which is a signal light of a first wavelength group among the wavelength groups previously assigned to each of the plurality of slave station devices. And a slave station reception signal which is signal light of the second wavelength group of the wavelength groups And a part of the parent station transmission signal light transmitted from the parent station device to the first transmission path to be demultiplexed and extracted as a first received signal light, and A function of inputting the station transmission signal light to the first transmission path, and a second reception by demultiplexing a part of the master station transmission signal light transmitted from the master station apparatus to the second transmission path A group multiplexing / demultiplexing unit having a function of extracting the slave station transmission signal light to the second transmission path and extracting the slave station transmission signal light to the second transmission path; and a level of the master station transmission signal light in the first transmission path; A switching control unit that outputs a switching instruction signal based on at least one of the levels of the master station transmission signal light in the second transmission path; and the first received signal light and the second based on the switching instruction signal Any of the received signal lights of the slave station is received as the slave station received signal light. And a switching unit that switches a transmission path to which the slave station transmission signal light is input to either the first transmission path or the second transmission path based on the switching instruction signal. The plurality of slave station devices are configured such that wavelengths included in the wavelength group pre-assigned to the plurality of slave station devices do not overlap each other, and each of the plurality of slave station devices includes the first The plurality of slave station devices are configured such that the wavelength included in the wavelength group and the wavelength included in the second wavelength group do not overlap each other.

  According to the present invention, in a wavelength division multiplexing optical communication system adopting a ring-type or chain-type transmission line, the wavelength of the signal light transmitted / received to / from each of the plurality of slave station devices provided with the optical branching and coupling element in the master station device By providing means having a group switching function, a redundant configuration in units of wavelength groups unique to the slave station apparatus is made possible, so that both improvement in economic efficiency and securing of high reliability can be achieved.

1 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system according to Embodiment 1 of the present invention. FIG. 6 is a diagram illustrating an example of wavelengths of signal light transmitted and received by a plurality of slave station devices in the first embodiment. FIG. 6 is a diagram illustrating an example of wavelengths of uplink signal light and downlink signal light transmitted and received by a slave station device in Embodiment 1. FIG. 6 is a diagram illustrating another example of wavelengths of uplink signal light and downlink signal light transmitted and received by the slave station device in Embodiment 1. FIG. FIG. 10 is a diagram illustrating still another example of wavelengths of uplink signal light and downlink signal light transmitted and received by the slave station device in the first embodiment. It is a figure which shows an example of an internal structure of the group multiplexing / demultiplexing part shown by FIG. 4 is a flowchart showing a redundant configuration switching operation in the wavelength division multiplexing optical communication system according to the first embodiment. It is a block diagram which shows schematically the wavelength division multiplexing optical communication system which concerns on Embodiment 2 of this invention. It is a figure which shows an example of an internal structure of the wavelength group filter part shown by FIG. It is a block diagram which shows schematically the wavelength division multiplexing optical communication system which concerns on Embodiment 3 of this invention. It is a block diagram which shows schematically the wavelength division multiplexing optical communication system which concerns on Embodiment 4 of this invention. It is a figure which shows an example of an internal structure of the optical branching coupler shown by FIG. It is a block diagram which shows schematically the wavelength division multiplexing optical communication system which concerns on Embodiment 5 of this invention. It is a figure which shows an example of an internal structure of the group multiplexing / demultiplexing part shown by FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the component to which the same code | symbol was attached | subjected in drawing has the same function. Further, the following description of the embodiment is an exemplification, and various modifications can be made within the scope of the present invention.

<< 1 >> Embodiment 1
<< 1-1 >> Configuration FIG. 1 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, a wavelength division multiplexing optical communication system 1 includes a master station device 10, a plurality of slave station devices (# 1 to #N) 1101,. One optical fiber 61, 62, 63 is provided. Here, N is an integer of 2 or more indicating the number of slave station devices.

  The optical fibers 61, 62, and 63 are connected to the second of the master station device 10 from the first input / output terminal 41 of the master station device 10 via the plurality of slave station devices (# 1 to #N) 1101,. A master station device 10 and a plurality of slave station devices (# 1 to #N) 1101,..., 1901 are connected in a ring shape returning to the input / output terminal 42 (that is, so as to constitute a ring network). The optical fibers 61, 62, and 63 have wavelength multiplexed signal light including signal light of one wavelength or more in a first direction (clockwise direction in FIG. 1) D1 (as 0-system, ie, operational wavelength multiplexed signal light) and 1 as a one-core bi-directional transmission path transmitted in a second direction (counterclockwise direction in FIG. 1) D2 that is the opposite direction of the first direction (as a wavelength-division multiplexed signal light of one system, ie, a standby system) The optical fiber of the heart.

  The master station device 10 is different from a plurality of optical transmitters 11_1 to 11_m, a multiplexer 12, and a transmission optical amplifier 13 for transmitting a plurality of signal lights M1_1,. A plurality of optical receivers 21_1 to 21_m for receiving a plurality of signal lights M1_1,..., M9_m having wavelengths, a duplexer 22, a reception optical amplifier 23, and an optical branching and coupling element 31 that is a passive element. have. The plurality of optical transmitters 11_1 to 11_m and the multiplexer 12 constitute a “parent station transmitter” that can transmit wavelength-multiplexed signal light (parent station transmission signal light). The duplexer 22 and the plurality of optical receivers 21_1 to 21_m constitute a “master station receiver” that can receive wavelength-multiplexed signal light (slave station transmission signal light). Here, m is an integer of 2 or more indicating the number of optical transmitters (also the number of optical receivers) in the master station device 10. Further, n is an integer of 2 or more indicating the number of wavelengths of signal light handled (supported) by each of the slave station devices (# 1 to #N) 1101,. Each of the plurality of slave station devices (# 1 to #N) 1101,..., 1901 handles signal light having a different wavelength group for each slave station device (that is, signal light having a unique wavelength group for each slave station device). Therefore, n is equal to the number of optical transmitters (the number of optical receivers) in each of the slave station devices (# 1 to #N) 1101,. The transmission optical amplifier 13 and the reception optical amplifier 23 are selected according to transmission conditions, and can be omitted when optical amplification is not required. Note that the wavelength group different for each slave station device means that the wavelengths included in the wavelength group assigned to each slave station device do not overlap each other.

  The multiplexer 12 is composed of an optical device such as an arrayed waveguide grating (AWG), and has a function of combining a plurality of input signal lights and outputting a wavelength multiplexed signal light. The demultiplexer 22 is composed of an optical device such as an AWG, and has a function of demultiplexing input wavelength multiplexed signal light and outputting signal light having a plurality of wavelengths.

  The transmission optical amplifier 13 and the reception optical amplifier 23 are, for example, erbium-doped fiber amplifiers (EDFAs), and have a function of amplifying the power of input signal light as signal light.

  The optical branching and coupling element 31 is, for example, a 2 × 2 port 3 dB optical branching coupler that is a passive optical coupler. The optical branching and coupling element 31 has, for example, first, second, third, and fourth ports 31a, 31b, 31c, and 31d, and a wavelength division multiplexed signal for transmission input from the first port 31a. The light is branched and output from the third port 31c and the fourth port 31d. Further, the wavelength multiplexed signal light for reception input to the third and fourth ports 31c and 31d are combined and output to the reception optical amplifier 23 via the second port 31b.

  The slave station device (# 1) 1101 includes a plurality of optical transmitters 111_1 to 111_n that can output a plurality of signal lights S1_1 to S1_n, a multiplexer 112, a transmission switch 113, and a plurality of signals. A plurality of optical receivers 121_1 to 121_n that can respectively receive the light S1_1 to S1_n, a demultiplexer 122, a receiving switch 123, a group multiplexing / demultiplexing unit 131, and a switching control unit (alarm monitoring unit) 132. The plurality of optical transmitters 111_1 to 111_n and the multiplexer 112 constitute a “slave station transmitter” that transmits transmission signal light that is wavelength-multiplexed signal light for transmission. The duplexer 122 and the plurality of optical receivers 121_1 to 121_n constitute a “slave station receiver” that receives the received signal light, which is a wavelength-multiplexed signal light for reception.

  The slave station device (#N) 1901 includes a plurality of optical transmitters 911_1 to 911_n that can output a plurality of signal lights S9_1 to S9_n, a multiplexer 912, a transmission switch 913, and a plurality of signals. A plurality of optical receivers 921_1 to 921_n capable of receiving the light S9_1 to S9_n, a demultiplexer 922, a receiving switch 923, a group multiplexing / demultiplexing unit 931, and a switching control unit (alarm monitoring unit) 932. The slave station device (#N) 1901 has the same configuration as that of the slave station device (# 1) 1101, but the wavelengths of a plurality of signal lights included in the wavelength multiplexed signal light handled by the slave station device (#N) 1901 (That is, the wavelength group) is different from the wavelengths (that is, the wavelength group) of the plurality of signal lights included in the wavelength multiplexed signal light handled by the slave station device (# 1) 1101. That is, the wavelength group signal light handled by the group multiplexing / demultiplexing unit 131 and the wavelength group signal light handled by the group multiplexing / demultiplexing unit 931 are different. Such a relationship also exists between the duplexer 122 and the duplexer 922, between the multiplexer 112 and the multiplexer 912, and between the optical transmitters 111_1 to 111_n and the optical transmitters 911_1 to 911_n. apply.

  The plurality of slave station devices (# 1 to #N) 1101,..., 1901 in the first embodiment have the same configuration, but the wavelength of the signal light included in the wavelength multiplexed signal light to be handled (supported) (That is, wavelength groups) are different from each other, that is, do not overlap each other. That is, a group multiplexing / demultiplexing unit (for example, 131 and 931 in FIG. 1), a demultiplexer (for example, 122 and 922 in FIG. 1), a multiplexer (for example, 112 and 912 in FIG. 1), an optical transmitter ( For example, the wavelengths of the plurality of signal lights handled in 111_1 to 111_n and 911_1 to 911_n in FIG. 1 are different for each slave station device.

<< 1-2 >> Operation Next, operations of the master station device 10 and the slave station devices (# 1 to #N) 1101,..., 1901 of the wavelength division multiplexing optical communication system 1 according to the first embodiment will be described. Since the operations of the slave station devices (# 1 to #N) 1101,..., 1901 are similar to each other, the operation of the slave station device (# 1) 1101 will be described as a representative example.

  The transmission direction (propagation direction) from the master station device 10 through the optical fiber 61 to the slave station device (# 1) 1101 and the transmission direction from the master station device 10 through the optical fibers 62 and 63 to the slave station device (# 1) 1101 It is referred to as “downward direction”, and the transmitted signal light is referred to as “downstream signal light”. Further, the transmission direction from the slave station device (# 1) 1101 to the master station device 10 through the optical fiber 61 and the transmission direction from the slave station device (# 1) 1101 to the master station device 10 through the optical fibers 63 and 62 are defined as “upstream”. The signal light to be transmitted is referred to as “upstream signal light”.

  First, downlink signal light will be described. User signals (transmission signals) provided from a master station side downstream device (not shown) connected to the master station device 10 are input to the optical transmitters 11_1 to 11_n of the master station device 10 and specified for wavelength multiplexing. , M9_n, and then transmitted to the multiplexer 12. Examples of specific wavelengths for wavelength multiplexing are shown in FIGS. 2 to 5 to be described later.

  The multiplexer 12 receives signal lights M1_1,..., M9_n having different wavelengths (for example, wavelengths λ1_1,..., Λ9_n in FIG. 2 to be described later) from the optical transmitters 11_1 to 11_n, and multiplexes them. Wavelength multiplexed signal light is generated, and this wavelength multiplexed light is transmitted to the transmission optical amplifier 13.

  The wavelength multiplexed signal light output from the multiplexer 12 is optically amplified by the transmission optical amplifier 13 and input to the optical branching and coupling element 31. If the transmission optical amplifier 13 is not installed according to the system requirements, the wavelength multiplexed signal light output from the multiplexer 12 is directly input to the optical branching and coupling element 31.

  The wavelength multiplexed signal light output from the transmission optical amplifier 13 is input to the optical branching and coupling element 31 from the first port 31a, branched into two in the optical branching and coupling element 31, and the third port 31c and the first input The signal is transmitted to the optical fiber 61 through the output terminal 41 and transmitted to the optical fiber 62 through the fourth port 31 d and the second input / output terminal 42. In the first embodiment, the solid line portion in the optical branching and coupling element 31 in FIG. 1 indicates the redundant operation system (system 0) of the transmission line, and the broken line portion indicates the standby system (1) of the transmission line redundancy configuration. System).

  In FIG. 1, the wavelength multiplexed signal light is transmitted in parallel from the master station device 10 to the optical fiber 61 and the optical fiber 62. In the system shown in FIG. 1, the transmission path for transmitting the wavelength multiplexed signal light (first master station transmission signal light) in the clockwise direction (first direction D1) through the optical fiber 61 is the operating system (system 0). The transmission path for transmitting wavelength multiplexed signal light (second master station transmission signal light) in the counterclockwise direction (second direction D2) through the optical fiber 62 is a standby system (system 1). Wavelength multiplexed signal light transmitted in parallel from the first input / output terminal 41 and the second input / output terminal 42 of the master station device 10 is transmitted through the optical fiber 61 and the optical fiber 62 in the first direction D1 and the second direction. 2 are respectively transmitted in the direction D2 and multiplexed / demultiplexed by a plurality of slave station devices (# 1 to #N) 1101,..., 1901 (that is, multiplexed / demultiplexed in units of wavelength groups unique to the slave station devices). )

  FIG. 2 is a diagram illustrating an example of the wavelength of signal light transmitted and received by the plurality of slave station devices (# 1 to #N) 1101,..., 1901 in the first embodiment. The wavelength (wavelength group) of the plurality of signal lights handled in each of the slave station devices (# 1 to #N) 1101,..., 1901 is the slave station device (# 1 to #N) as shown in FIG. 1101,..., 1901 are different from each other, that is, do not overlap each other. In other words, each of the slave station devices (# 1 to #N) 1101,..., 1901 is assigned a fixed wavelength and a wavelength group to be handled (supported). In this case, the number of signal lights handled by the master station device 10 is m (m = N × n in FIG. 1), which is the number of all signal lights handled by the system, but the slave station devices (# 1 to # 1). #N) 1101,..., 1901 each handle the number of wavelengths of signal light is n, which is less than m. In this way, since the number n of signal lights handled by each of the slave station devices (# 1 to #N) 1101,..., 1901 is a small number, the slave station devices (# 1 to #N) 1101, ... 1901 is an economical optical device that can reduce the price.

  In addition, although wavelength division multiplexed light transmission technology utilizes wavelength independence and direction independence, in actual operation, interference due to crosstalk or the like may not be negligible depending on the performance of the optical device. In particular, when the single-core bidirectional transmission method is adopted, signal lights having different wavelengths are used for transmission in the upstream and downstream directions in a single-fiber transmission line. FIG. 3 is a diagram illustrating an example of wavelengths of uplink signal light and downlink signal light transmitted and received by slave station devices (# 1 to #N) 1101,..., 1901 in the first embodiment. As shown in FIG. 3, for example, in the range of a wavelength group (wavelength group predetermined for each slave station apparatus) of signal light wavelengths λ1_1 to λ1_n handled by the slave station apparatus (# 1) 1101 is short. Wavelength group (second wavelength group) of downstream signal light (slave station received signal light) is arranged on the wavelength side, and wavelength group of upstream signal light (slave station transmission signal light) on the long wavelength side across the guard wavelength band By arranging the (first wavelength group), interference such as crosstalk can be reduced. Here, the guard wavelength band indicates a wavelength band that cannot be used due to the characteristics of a wavelength filter used to separate upstream signal light and downstream signal light.

  FIG. 4 is a diagram illustrating another example of wavelengths of upstream signal light and downstream signal light transmitted and received by the slave station devices (# 1 to #N) 1101,..., 1901 in the first embodiment. In FIG. 4, the wavelengths of the upstream signal light (for example, λ1_2, λ1_4,..., Λ1_n) and the wavelengths of the downstream signal light (for example, λ1_1, λ1_3,. Is the wavelength of the downstream signal light, and the even-numbered wavelength is the wavelength of the upstream signal light. The example of the wavelength of the signal light shown in FIG. 4 is a system that can multiplex / demultiplex even-numbered wavelength signal light and odd-numbered wavelength signal light by using an optical device such as an optical interleaver. Used for. In other words, among the wavelength groups assigned in advance to each of the plurality of slave station devices (# 1 to #N), the signal light of the first wavelength group used as the slave station transmission signal light, and the slave station received signal The signal light of the second wavelength group used as light is alternately arranged in order from the short wavelength side.

  FIG. 5 is a diagram showing still another example of wavelengths of uplink signal light and downlink signal light transmitted and received by the slave station devices (# 1 to #N) in the first embodiment. In FIG. 3, the wavelength of the upstream signal light and the wavelength of the downstream signal light are mixed within the band of the wavelength group assigned to the slave station device (# 1) 1101, but in FIG. 5, the wavelength λ1_1_u of the upstream signal light is mixed. An example is shown in which a wavelength group of ˜λ1_n_u and a wavelength group of wavelengths λ1_1_d to λ1_n_d of downstream signal light are separated with a guard wavelength region interposed therebetween. In this case, the guard wavelength region, which is an unused wavelength band by the wavelength filter, is shared by the entire wavelength band (that is, one guard wavelength region is not provided for each wavelength group, but one guard wavelength region is provided for the entire wavelength band). Since the region is provided), the wavelength band can be used effectively. However, the group demultiplexing and group multiplexing in each of the slave station devices (# 1 to #N) 1101,..., 1901 are two wavelength groups (that is, the wavelength group and group of the optical signal to be subjected to group demultiplexing). It is necessary to correspond to the wavelength group of the optical signal to be multiplexed. In the master station device 10, all of the wavelengths λ1_1,..., Λ9_n of signal light handled by the plurality of slave station devices (# 1 to #N) 1101,. It is demultiplexed.

  As shown in FIG. 2, in the first embodiment, a plurality of slave station devices are used so that wavelengths included in a wavelength group assigned in advance to the plurality of slave station devices (# 1 to #N) do not overlap each other. (# 1 to #N) are configured. Further, as shown in FIGS. 3 to 5, the wavelength included in the first wavelength group and the wavelength included in the second wavelength group in each of the plurality of slave station devices (# 1 to #N) are mutually different. A plurality of slave station devices (# 1 to #N) are configured so as not to overlap.

  Next, slave station device (# 1) 1101 will be described. Wavelength multiplexed signal light (first master station transmission signal light) transmitted from the master station device 10 through the optical fiber 61 and wavelength multiplexed signal light (second master signal transmitted from the master station device 10 through the optical fibers 62 and 63). The station transmission signal light) is received by the group multiplexing / demultiplexing unit 131 of the slave station device (# 1) 1101.

  FIG. 6 is a diagram illustrating an example of an internal configuration of the group multiplexing / demultiplexing unit 131 illustrated in FIG. As shown in FIG. 6, the group multiplexing / demultiplexing unit 131 includes an optical coupler unit 131a, a demultiplexing optical bandpass filter (OBPF: Optical Band-Pass Filter) 131c for the first direction D1 (operation system), For the first direction D1 (active system) combined optical bandpass filter 131d, for the second direction D2 (standby system) combined optical bandpass filter 131e, and for the second direction D2 (standby system) It has a waveband filter 131f and an optical coupler 131b.

  The demultiplexing optical bandpass filter 131c uses signal light of a wavelength group assigned to the slave station device (# 1) 1101 (for example, λ1_1, λ1_3 in FIG. 4) from the wavelength multiplexed signal light transmitted in the first direction D1. ... Λ1_n−1) has a function of demultiplexing. The demultiplexing optical bandpass filter 131f uses wavelength multiplexed signal light transmitted in the second direction D2 and wavelength group signal light (for example, λ1_2, λ1_4 in FIG. 4) assigned to the slave station device (# 1) 1101. ..., λ1_n) has a function of demultiplexing. As the signal light of the wavelength group assigned to the slave station device (# 1) 1101, for example, any one of the wavelength arrays shown in FIGS. 3 to 5 can be adopted.

  In the demultiplexing optical bandpass filter 131c of the group multiplexing / demultiplexing unit 131, the wavelength group signal light for the slave station device (# 1) 1101 is demultiplexed from the wavelength multiplexed signal light transmitted in the first direction D1, The demultiplexed signal light of the wavelength group is transmitted to the reception switch 123 and the switching control unit 132. Similarly, the demultiplexing optical bandpass filter 131f of the group multiplexing / demultiplexing unit 131 demultiplexes the signal light of the wavelength group for the slave station device (# 1) 1101 from the wavelength multiplexed signal light transmitted in the second direction D2. The signal light of the wavelength group that is waved and demultiplexed is transmitted to the receiving switch 123 and the switching control unit 132.

  The switching control unit 132 is transmitted in the second direction D2 and the operation system signal light (0-system signal light) that is the wavelength multiplexed signal light (first master station transmission signal light) transmitted in the first direction D1. The optical level (optical power) of the standby system signal light (system 1 signal light) that is the wavelength multiplexed signal light (second master station transmission signal light) is monitored, and this optical level is set to a preset optical level ( When the value falls below (threshold value), it has a function of notifying a switching instruction signal to the receiving switch 123 and the transmitting switch 113.

  The receiving switch 123 includes a path selectable optical device such as a 1 × 2 port optical switch, and in accordance with a switching instruction signal output from the switching control unit 132, the transmission switch to be used is set to the active transmission line and the standby switch. The signal light of the signal group provided from the selected transmission line is output to the demultiplexer 122 by selecting and switching from any of the transmission lines.

  The demultiplexer 122 demultiplexes the input wavelength multiplexed signal light into a plurality of signal lights, and outputs the plurality of signal lights S1_1 to S1_n obtained by the demultiplexing to the optical receivers 121_1 to 121_n, respectively. The optical receivers 121_1 to 121_n transmit a signal based on the received signal light to the slave station side downstream device.

  Next, uplink signal light in slave station apparatus (# 1) 1101 will be described. A transmission signal as a user signal provided from the downstream device on the slave station side is input to the optical transmitters 111_1 to 111_n of the slave station device (# 1) 1101, and specific wavelengths for wavelength multiplexing are transmitted by the optical transmitters 111_1 to 111_n. After being converted into (wavelength group) signal light, it is output to the multiplexer 112. The multiplexer 112 has a function of multiplexing the input signal light having a plurality of wavelengths.

  The multiplexer 112 receives a plurality of signal lights S1_1 to S1_n having different wavelengths from the optical transmitters 111_1 to 111_n, combines them, and outputs them to the transmission switch 113.

  The transmission switch 113 has a path selectable optical device such as a 1 × 2 port optical switch similar to the reception switch 123, and is in accordance with a switching instruction signal output from the switching control unit 132. The wavelength multiplexed signal light output from 112 is transmitted to either the optical fiber 61 (second direction D2) or the optical fiber 63 (first direction D1) via the group multiplexing / demultiplexing unit 131.

  Each of the slave station devices (# 1 to #N) 1101,..., 1901 switches the transmission signal so that the same transmission path as the transmission path of the received signal is used. For example, when the slave station device (# 1) 1101 receives downlink signal light from the master station device 10 through the optical fiber 61 in the first direction D1, the uplink output from the slave station device (# 1) 1101 The signal light is transmitted to the master station device 10 through the optical fiber 61 in the second direction D2. Such a configuration is useful when applied to a network such as MFH in which the delay difference between upstream signal light and downstream signal light needs to be kept small.

  Next, the operation of the master station device 10 that has received the upstream signal light received from the slave station device via the optical fiber 61 and the upstream signal light received from the slave station device via the optical fibers 63 and 62 will be described. The master station device 10 converts the wavelength multiplexed signal light output from the slave station devices (# 1 to #N) 1101,..., 9101 transmitted in the first direction D1 and the second direction D2 into optical branching and coupling elements. Receive at 31.

  In the optical branching and coupling element 31, the wavelength multiplexed signal light provided from the optical fiber 61 and the wavelength multiplexed signal light provided from the optical fiber 62 are combined, and the wavelength multiplexed signal light generated by the combination is supplied to the reception optical amplifier 23. Output.

  Similarly to the transmission optical amplifier 13, the reception optical amplifier 23 optically amplifies the received wavelength multiplexed signal light and transmits the optically amplified wavelength multiplexed signal light to the demultiplexer 22.

  The demultiplexer 22 demultiplexes the received wavelength multiplexed signal light for each wavelength, and transmits a plurality of signal lights M1_1,..., M9_n obtained by the demultiplexing to the plurality of optical receivers 21_1 to 21_m. The optical receivers 21_1 to 21_m transmit a signal based on the received optical signal to the connected master station side downstream device.

  Next, the redundancy switching process in the first embodiment will be described. In the first embodiment, each of the slave station devices (# 1 to #N) 1101,..., 9101 independently determines the switching condition of the switching control unit (alarm monitoring unit) (eg, 113, 913). Perform redundancy switching.

  FIG. 7 is a flowchart showing the switching operation of the redundant configuration in the wavelength division multiplexing optical communication system 1 according to the first embodiment. FIG. 7 illustrates the redundant switching performed by the switching control of the reception switch 123 and the transmission switch 113 performed by the switching control unit 132 of the slave station device (# 1) 1101.

  In the redundant switching, the “automatic” setting for detecting the presence / absence of a failure in each of the slave station devices (# 1 to #N) 1101,..., 9101 and performing the redundant switching based on the detection result, and the failure occurred. Even in this case, there is a “fixed” setting in which redundancy switching is not performed. Since the operations of the slave station devices (# 1 to #N) 1101,..., 9101 are similar to each other, the slave station device (# 1) 1101 will be described. When the redundancy switching process shown in FIG. 7 starts, first, in step ST1, the switching control unit 132 determines whether the switching mode is automatic or fixed. If it is determined in step ST1 that the switching mode in the slave station device (# 1) 1101 is “fixed”, this processing flow ends. If it is determined in step ST1 that the switching mode in the slave station device (# 1) 1101 is “automatic”, the process proceeds to step ST2.

  In step ST2, the switching control unit 132 reads the input light level of the active transmission line. After the reading in step ST2 is completed, the process proceeds to step ST3.

  In step ST3, the switching control unit 132 determines whether or not the input light level of the active transmission line is a level at which service can be continued. Specifically, the switching control unit 132 compares the input light level of the active transmission line read out in step ST2 with a predetermined specified level, and the input light level of the active transmission line is equal to or higher than the specified level. The case is determined as “normal” and the case lower than the specified level is determined as “abnormal”. Note that the predetermined level set in advance can be changed by the user according to the network status.

  If it is determined as “normal” in step ST2, the switching control unit 132 returns to step ST1 because it is not necessary to perform redundant switching. When it is determined as “abnormal” in step ST2, the switching control unit 132 advances the process to step ST4.

  In step ST4, the switching control unit 132 reads the input light level of the standby transmission path, and the process proceeds to step ST5.

  In step ST5, the switching control unit 132 determines whether or not the optical input level of the standby transmission line is a level at which service can be continued after redundant switching. Specifically, as in the process of step ST3, the switching control unit 132 compares the light input level with a predetermined specified level, and determines that the case where the light input level is equal to or higher than the specified level is “normal”. If it is lower, it is determined as “abnormal”. Here, when it is determined as “abnormal”, no switching is performed to indicate that both the active transmission line and the standby transmission line have failed or the service has not started, and step ST1 is performed. Return to, and execute the processing flow again in order. If it is determined as “normal” in step ST5, the process proceeds to step ST6 in order to perform redundancy switching to the standby transmission line.

  In step ST6, the switching control unit 132 outputs a switching instruction signal to the reception switch 123 and the transmission switch 113.

  In step ST7, after receiving the setting completion results of the reception switch 123 and the transmission switch 113, the switching control unit 132 moves the process to step ST1. In FIG. 7, the optical level of the wavelength multiplexed signal light is monitored and the presence / absence of an abnormality is determined based on a preset specified level. For example, the monitoring control signal light transmitted through the optical fiber 61 or It is also possible to monitor the dummy control light and the dummy control signal light or the dummy light transmitted through the optical fibers 62 and 63, detect a decrease in light level or signal quality, and output a switching instruction signal according to the detection result. is there.

<< 1-3 >> Effect As described above, in the wavelength division multiplexing optical communication system 1 according to the first embodiment, the transmission path to be used is switched by the slave station devices (# 1 to #N) 1101,. Since the wavelength group unit assigned to each of 1901 is set, the number of optical switches corresponding to the number of wavelengths required in the conventional configuration can be greatly reduced. For this reason, the network cost can be significantly reduced. In other words, in the wavelength multiplexing optical communication system 1 according to the first embodiment, each of the plurality of slave station devices (# 1 to #N) 1101,. 2 optical switchers) is required, but the number of optical switchers can be significantly reduced compared to the conventional configuration with the number of optical switchers corresponding to the number of wavelengths, greatly reducing costs. can do.

  Further, in the conventional configuration, since it is assumed that the master station device has a switch switching function, the master station device is either a wavelength-division multiplexed signal of either an operational optical fiber or a preparation optical fiber (standby system). Only the light was received. On the other hand, in the wavelength division multiplexing optical communication system 1 according to the first embodiment, a passive 2 × 2 port 3 dB optical branching coupler is used as the optical branching coupling element 31 of the master station device 10, so that the optical fiber 61 ( Wavelength multiplexed signal light provided from both the operation system) and the optical fiber 62 (preparation system) can always be received. As described above, according to the wavelength division multiplexing optical communication system 1, since wavelength division multiplexed signal light can be received from two systems at all times, higher reliability can be ensured as compared with the conventional system. Further, according to the wavelength division multiplexing optical communication system 1, switching is performed only by the transmission switch and reception switch of all the slave station devices (# 1 to #N), and the master station device has a switch switching function. Since a 3 dB optical branching coupler, which is an inexpensive passive element, can be provided instead of the optical device having a low cost, the cost can be reduced and the economy can be improved.

  In addition, the wavelength division multiplexing optical communication system 1 according to Embodiment 1 applies the master station device 10 to the BBU and applies a plurality of slave station devices (# 1 to #N) to a plurality of RRHs, respectively. Applicable to MFH. When the reception switch 123 and the transmission switch 113 of the slave station device (# 1) 1101 are arranged in the same node or in the same card, the upstream signal light and the downstream signal light, such as MFH, are transmitted. This is particularly effective when it is necessary to arrange the routes at high speed.

<< 2 >> Embodiment 2
<< 2-1 >> Configuration FIG. 8 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system 2 according to Embodiment 2 of the present invention. In FIG. 8, the same reference numerals as those shown in FIG. 1 are given to the same or corresponding elements as those shown in FIG. In the wavelength division multiplexing optical communication system 2 according to the second embodiment, the slave station devices (# 1 to #N) 2101 instead of the slave station devices (# 1 to #N) 1101,. .., 2901 are different from the wavelength division multiplexing optical communication system 1 according to the first embodiment. Therefore, the differences will be mainly described below.

  The slave station device (# 1) 2101 receives a plurality of optical transmitters 111_1 to 111_n, a multiplexer 112, and a plurality of signal lights S1_1 to S1_n that can output a plurality of signal lights S1_1 to S1_n, respectively. A plurality of optical receivers 121_1 to 121_n, a demultiplexer 122, an optical coupling unit 141 as a group multiplexing / demultiplexing unit, a transmission / reception switch 142, a switching control unit 143, and a wavelength group filter unit 144.

  The slave station device (#N) 2901 receives a plurality of optical transmitters 911_1 to 911_n, a multiplexer 912, and a plurality of signal lights S9_1 to S9_n, which can output a plurality of signal lights S9_1 to S9_n, respectively. A plurality of optical receivers 921_1 to 921_n, a demultiplexer 922, an optical coupling unit 941, a transmission / reception switch 942, a switching control unit 943, and a wavelength group filter unit 944. .

  The slave station devices (# 1 to #N) 2101,..., 2901 have the same configuration, but have different wavelengths (that is, wavelength groups) of the signal light included in the used wavelength multiplexed signal light. In other words, as shown in FIG. 2, in the second embodiment, a plurality of wavelengths are included so that wavelengths included in a wavelength group assigned in advance to a plurality of slave station devices (# 1 to #N) do not overlap each other. Slave station devices (# 1 to #N) are configured. Further, as shown in FIGS. 3 to 5, in each of the plurality of slave station devices (# 1 to #N), the wavelength included in the first wavelength group for slave station transmission signal light and the slave station reception A plurality of slave station devices (# 1 to #N) are configured so that the wavelengths included in the second wavelength group do not overlap each other.

  The slave station device (# 1) 2101 according to the second embodiment includes the optical coupling unit 141 as a group multiplexing / demultiplexing unit, so that the optical loss in the slave station device (# 1) 2101 increases. The difference from Embodiment 1 is that switching is performed by one transmission / reception switch 142.

  Since the configurations and operations of the slave station devices (# 1 to #N) 2101,..., 2901 are similar to each other, the configuration and operation of the slave station device (# 1) 2101 will be described as a representative example. FIG. 9 is a diagram illustrating an example of an internal configuration of the wavelength group filter unit 144 illustrated in FIG. 8.

  The wavelength multiplexed signal light transmitted in the first direction D1 through the optical fiber 61 and the wavelength multiplexed signal light transmitted in the second direction D2 through the optical fibers 62 and 63 are the wavelength of the slave station device (# 1) 2101. Received by the group filter unit 144. As shown in FIG. 9, the wavelength group filter unit 144 includes an optical coupler 144 a on the optical fiber 61 side, an optical coupler 144 b on the optical fiber 63 side, and wavelength multiplexed signal light transmitted from the optical fiber 61 to the optical fiber 63. And an optical bandpass filter 144c that blocks the wavelength band used by the slave station device (# 1) 2101 and transmits other wavelengths among the wavelength multiplexed signal light transmitted from the optical fiber 63 to the optical fiber 61. have.

<< 2-2 >> Operation The wavelength group filter unit 144 is a 1 × 2 optical coupler (FIG. 2) that is an element having a simple configuration for combining / demultiplexing the first direction D1 and combining / demultiplexing the second direction D2. 9 can be carried out simultaneously in 144a and 144b). Since the optical couplers 144a and 144b do not have wavelength filter characteristics and transmit the wavelength that is group-demultiplexed by the slave station device (# 1) 2101 and interfere with the wavelength that is multiplexed, the optical band-pass filter 144c Cut the wavelength for group demultiplexing.

  The wavelength multiplexed signal light obtained by branching by the wavelength group filter unit 144 is transmitted to the transmission / reception switch 142 and the switching control unit 143.

  The signal light received by the transmission / reception switch 142 is transmitted to the optical coupling unit 141 through a path in the set direction (first direction D1 or second direction D2).

  The optical coupling unit 141 includes a 1 × 2 port 3 dB optical coupler, a blue band wavelength filter that transmits blue band light, and a red band light that passes red band light according to the wavelength arrangement shown in FIGS. It is composed of a band wavelength filter, an optical interleaver, and the like, and is transmitted to the duplexer 122 and the multiplexer 112.

  The wavelength multiplexed signal light transmitted from the optical coupler 141 to the demultiplexer 122 is demultiplexed by the demultiplexer 122 to become signal light of individual wavelengths, and is transmitted to the optical receivers 121_1 to 121_n. The optical receivers 121_1 to 121_n transmit signals corresponding to the received signal light to the slave station side downstream device.

  The signal light transmitted from the optical transmitters 111_1 to 111_n to the multiplexer 112 is a wavelength at which the upstream signal light and the downstream signal light are different from each other as shown in any of FIGS. By doing so, wavelength interference is not generated, and the received downstream signal light is discarded as it is. That is, even when the wavelength group of the downstream signal light is transmitted from the optical coupling unit 141, the multiplexer 112 is blocked by the wavelength-dependent multiplexer 112 and does not affect the main signal.

  Next, the flow of upstream signal light output from slave station devices (# 1 to #N) 2101,. User signals provided from the slave station side downstream devices are input to the optical transmitters 111_1 to 111_n of the slave station devices (# 1 to #N) 2101, converted into specific wavelengths for wavelength multiplexing, and then multiplexed. To the instrument 112.

  Signal light having different wavelengths are received from the optical transmitters 111_1 to 111_n, combined by the multiplexer 112, and then transmitted to the optical coupling unit 141 as wavelength multiplexed signal light. The wavelength multiplexed signal light is transmitted from the optical coupling unit 141 to the transmission / reception switch 142, selects a route according to the switching instruction signal of the switching control unit 143, and is transmitted to the wavelength group filter unit 144. The wavelength multiplexed signal light output from the switching control unit 143 is transmitted from the wavelength group filter unit 144 to the optical fiber 61 or the optical fiber 63.

  The flow of upstream signal light received from the optical fiber 61 and the optical fiber 62 in the master station device 10 is the same as that in the first embodiment. Further, the switching process at the time of redundancy is the same as that in the first embodiment.

<< 2-3 >> Effect As described above, according to the wavelength division multiplexing optical communication system 2 according to the second embodiment, the switching units in the slave station devices (# 1 to #N) 2101,. By using one transmission / reception switch 142, the configuration can be simplified. Specifically, by adopting the transmission / reception switch 142, which is an expensive optical switch, the number of optical switches is reduced to one, so that the number of components can be reduced as compared with the first embodiment. This can reduce the cost.

  Note that the transmission / reception switch 142 of the slave station devices (# 1 to #N) 2101,..., 9201 performs transmission and reception switching at the same time. This is effective when it is necessary to align the path with light at high speed.

  Except for the above, the second embodiment is the same as the first embodiment.

<< 3 >> Embodiment 3
<< 3-1 >> Configuration FIG. 10 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system 3 according to Embodiment 3 of the present invention. 10, components that are the same as or correspond to the components shown in FIG. 8 are given the same reference numerals as those shown in FIG. In the wavelength division multiplexing optical communication system 3 according to the third embodiment, the slave station devices (# 1 to #N) 3101 are replaced with the slave station devices (# 1 to #N) 2101 ... 2901 in the second embodiment. .., 3901, and in that the master station device 10 and a plurality of slave station devices (# 1 to #N) 3101,..., 3901 are connected in a chain form by optical fibers 64 to 67. This is different from the wavelength division multiplexing optical communication system 2 according to the second embodiment. The optical fibers 64 to 67 are single-core optical fibers, and the optical fiber 64 and the optical fiber 66 as the first transmission path are the operation system transmission path (system 0) and the optical fiber 65 as the second transmission path. And an optical fiber 67 indicate a standby transmission line (system 1). Therefore, the following description will focus on differences from the first and second embodiments.

  The slave station device (# 1) 3101 receives a plurality of optical transmitters 111_1 to 111_n, a multiplexer 112, and a plurality of signal lights S1_1 to S1_n that can output a plurality of signal lights S1_1 to S1_n, respectively. A plurality of optical receivers 121_1 to 121_n, a demultiplexer 122, an optical coupling unit 151 as a group multiplexing / demultiplexing unit, a transmission path switch 152 as a switching unit, a switching control unit 153, An optical branch coupler 154 and an optical branch coupler 155 are provided. The configuration and function of the optical coupling unit 151 are the same as those of the optical coupling unit 141 in the second embodiment.

  The slave station apparatus (#N) 3901 receives a plurality of optical transmitters 911_1 to 911_n, a multiplexer 912, and a plurality of signal lights S9_1 to S9_n, which can output a plurality of signal lights S1_1 to S1_n, respectively. A plurality of optical receivers 921_1 to 921_n, a demultiplexer 922, an optical coupling unit 951 as a group multiplexing / demultiplexing unit, a transmission / reception switch 952, a switching control unit 953, and an optical branching coupler 954 and an optical branching coupler 955. The configuration and function of the optical coupling unit 951 are the same as those of the optical coupling unit 141 in the second embodiment.

  The slave station devices (# 1 to #N) 3101,..., 3901 have the same configuration, but the wavelengths of the signal light (that is, wavelength groups) included in the used wavelength multiplexed signal light are different from each other. As shown in FIG. 2, in the third embodiment, a plurality of slave station devices are used so that wavelengths included in a wavelength group assigned in advance to the plurality of slave station devices (# 1 to #N) do not overlap each other. (# 1 to #N) are configured. Further, as shown in FIG. 3 to FIG. 5, the wavelengths included in the first wavelength group for the slave station transmission signal light and the slave station received signal light in each of the plurality of slave station devices (# 1 to #N). The plurality of slave station devices (# 1 to #N) are configured so that the wavelengths included in the second wavelength group for use do not overlap each other.

<3-2> Operation Next, the operation of the wavelength division multiplexing optical communication system 3 according to Embodiment 3 will be described. Since the operations of the slave station devices (# 1 to #N) 3101,..., 3901 are similar to each other, the operation of the slave station device (# 1) 3101 will be described as a representative example.

  The flow of signal light in the master station device 10 is the same as that in the first and second embodiments. The optical branching and coupling element 31 is connected to the optical fiber 64 and the optical fiber 65, and transmits / receives wavelength multiplexed signal light through the first input / output terminal 41 and the second input / output terminal 42.

  The wavelength division multiplexed signal light transmitted in parallel from the master station device 10 is multiplexed / demultiplexed by the slave station devices (# 1 to #N) 3101,..., 3901 through the optical fiber 64 and the optical fiber 65.

  The flow of downstream signal light of the slave station device (# 1) 3101 will be described. The wavelength multiplexed signal light transmitted through the optical fiber 64 and the wavelength multiplexed signal light transmitted through the optical fiber 65 are received by the optical branching coupler 154 and the optical branching coupler 155 of the slave station device (# 1) 3101, respectively. . The optical branching coupler 154 and the optical branching coupler 155 have a 1 × 2 port optical coupler, branch a part of signal light from the wavelength multiplexed signal light transmitted from the master station device 10, or wavelength multiplexed signals Couple signal light to light.

  The wavelength-division multiplexed signal light received from the optical fiber 64 that is the operational transmission line is partially branched by the optical branching coupler 154, transmitted to the transmission line switch 152 and the switching control unit 153, and transmitted through the transmission line switch 152. The data is input to the coupling unit 151. The wavelength-division multiplexed signal light that has not been branched by the optical branching coupler 154 is transmitted through the optical fiber 66 to the slave station devices (# 2 to #N) on and after the next stage.

  Similarly, the wavelength multiplexed signal light received from the optical fiber 65 serving as the standby transmission path is also partially branched by the optical branching coupler 155 and transmitted to the transmission path switch 152 and the switching control unit 153, and the transmission path switch 152. To the optical coupling unit 151. The wavelength multiplexed signal light that has not been branched by the optical branching coupler 155 is transmitted to the slave station devices (# 2 to #N) on and after the next stage via the optical fiber 67.

  The switching control unit 153 is at least one of the level of the master station transmission signal light in the optical fibers 64 and 66 as the first transmission path and the level of the master station transmission signal light in the optical fibers 65 and 67 as the second transmission path. Based on the above, a switching instruction signal is generated.

  Next, the flow of upstream signal light output from slave station devices (# 1 to #N) 3101,..., 3901 will be described. The signal flow from the user signal provided from the slave station side downstream device to the transmission path switch 152 is the same as that of the second embodiment.

  The transmission line switching unit 152 transmits either one of the optical fiber 64 that is the active transmission line and the optical fiber 65 that is the standby transmission line according to the switching instruction signal output from the switching control unit 153. Select. The transmission line switch 152 is an optical fiber selected by the switching control unit 153 via the optical branching coupler 154 or the optical branching coupler 155 (that is, an optical transmission line that is a wavelength division multiplexed signal light for transmission). The wavelength multiplexed signal light is transmitted to the fiber 64 or the optical fiber 65) which is a standby transmission line.

  The flow of upstream signal light received from the optical fiber 64 and the optical fiber 65 in the master station device 10 is the same as that in the first and second embodiments. Further, the switching process at the time of redundancy is the same as in the first and second embodiments.

<< 3-3 >> Effect As described above, in the wavelength division multiplexing optical communication system 3 according to Embodiment 3, the wavelength division multiplexed signal light multiplexed by the slave station apparatus (# 1) 3101 is transmitted to the master station apparatus. 10 and is not transmitted to the optical fiber 66 and the optical fiber 67 on the side of the slave station devices (# 2 to #N) on and after the second stage. Further, the wavelength division multiplexing optical communication system 3 employs a chain network, and does not perform communication in both directions such as the first direction D1 and the second direction D2, unlike the ring network. Therefore, the wavelength division multiplexing optical communication system 3 needs to include a wavelength filter (144c in FIG. 9) for preventing the wavelengths from interfering with each other between the optical fiber 61 and the optical fiber 63 as shown in the second embodiment. Therefore, it can be configured only with an optical filter having a simple configuration, and expensive optical devices can be reduced, which is effective in reducing the network cost.

  Except for the above, the third embodiment is the same as the first and second embodiments.

<< 4 >> Embodiment 4
<< 4-1 >> Configuration FIG. 11 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system 4 according to Embodiment 4 of the present invention. In FIG. 11, the same reference numerals as those shown in FIG. 10 are given to the same or corresponding elements as those shown in FIG. In the wavelength division multiplexing optical communication system 4 according to the fourth embodiment, the slave station devices (# 1 to #N) 4101 are replaced with the slave station devices (# 1 to #N) 3101,. .., 4901 are different from the wavelength division multiplexing optical communication system 3 according to the third embodiment. The master station device 10 and a plurality of slave station devices (# 1 to #N) 4101,..., 4901 are connected in a chain form by optical fibers 64-67. Each of the optical fibers 64 to 67 is a single optical fiber. The optical fiber 64 and the optical fiber 66 are an operation transmission line (system 0), and the optical fiber 65 and the optical fiber 67 are a standby transmission line (system 1). Indicates. Below, it demonstrates centering on difference with Embodiment 3. FIG.

  The slave station device (# 1) 4101 includes a plurality of optical transmitters 111_1 to 111_n, a multiplexer 112, a plurality of optical receivers 121_1 to 121_n, a duplexer 122, and light as a group multiplexing / demultiplexing unit. A coupling unit 151, a transmission path switch 163, a switching control unit 162, and an optical branching coupler 164 are included.

  The slave station device (#N) 4901 includes a plurality of optical transmitters 111_1 to 111_n, a multiplexer 912, a plurality of optical receivers 121_1 to 121_n, a demultiplexer 922, and light as a group multiplexing / demultiplexing unit. A coupling unit 951, a transmission / reception switch 963, a switching control unit 962, and an optical branching coupler 964 are provided.

  The slave station devices (# 1 to #N) 4101,..., 4901 have the same configuration, but have different wavelengths (that is, wavelength groups) of the signal light included in the wavelength multiplexed signal light used. As shown in FIG. 2, in the fourth embodiment, a plurality of slave station devices are used so that wavelengths included in a wavelength group assigned in advance to the plurality of slave station devices (# 1 to #N) do not overlap each other. (# 1 to #N) are configured. Further, as shown in FIG. 3 to FIG. 5, the wavelengths included in the first wavelength group for the slave station transmission signal light and the slave station received signal light in each of the plurality of slave station devices (# 1 to #N). The plurality of slave station devices (# 1 to #N) are configured so that the wavelengths included in the second wavelength group for use do not overlap each other.

  FIG. 12 is a diagram showing an example of the internal configuration of the optical branching coupler 164 shown in FIG. Of the wavelength multiplexed signal light transmitted through the optical fiber 64 and the wavelength multiplexed signal light transmitted through the optical fiber 65, the wavelength multiplexed signal light selected by the transmission path switch 163 is transmitted to the slave station device (# 1) 4101. It is received by the optical branching coupler 164. As shown in FIG. 12, the optical branching coupler 164 includes an optical coupler 164b on the transmission path switch 163 side and an optical coupler 164a on the optical fibers 66 and 67 side.

<< 4-2 >> Operation Next, the operation of the wavelength division multiplexing optical communication system 4 according to Embodiment 4 will be described. Since the operations of the slave station devices (# 1 to #N) 4101,..., 4901 are similar to each other, the operation of the slave station device (# 1) 4101 will be described as a representative example.

  The flow of signal light in the master station device 10 is the same as that in the first to third embodiments. The optical branching and coupling element 31 is connected to the optical fiber 64 and the optical fiber 65, and transmits / receives wavelength multiplexed signal light through the first input / output terminal 41 and the second input / output terminal 42.

  The wavelength multiplexed signal light transmitted from the master station device 10 is transmitted to the slave station device (# 1) 4101 via the optical fiber 64 and the optical fiber 65, and transmitted through the optical fiber 64. Of the wavelength multiplexed signal light transmitted through the fiber 65, the wavelength multiplexed signal light selected by the transmission path switch 163 is received by the optical branching coupler 164 of the slave station device (# 1) 4101, and the slave station device ( # 1) 4101 is multiplexed / demultiplexed.

  The flow of downstream signal light of slave station apparatus (# 1) 4101 will be described. The wavelength multiplexed signal light transmitted through the optical fiber 64 and the wavelength multiplexed signal light transmitted through the optical fiber 65 are input to the transmission path switch 163 of the slave station apparatus (# 1) 4101. The transmission path switch 163 outputs either the wavelength multiplexed signal light transmitted through the optical fiber 64 or the wavelength multiplexed signal light transmitted through the optical fiber 65 to the optical branching coupler 164. The optical branching coupler 164 has a 1 × 2 port optical coupler, branches a part of the signal light from the wavelength multiplexed signal light transmitted from the master station device 10, or couples the signal light to the wavelength multiplexed signal light. To do.

  The wavelength multiplexed signal light received from the optical fiber 64 that is the operational transmission line is input to the switching control unit 162, partly branched by the optical branching coupler 164, and transmitted to the optical coupling unit 151. The wavelength-division multiplexed signal light that has not been branched by the optical branching coupler 164 is transmitted through the optical fiber 66 to the slave station devices (# 2 to #N) on and after the next stage.

  The wavelength multiplexed signal light received from the optical fiber 65 that is the standby transmission line is input to the switching control unit 162.

  The transmission line switching unit 163 transmits the wavelength-multiplexed signal light for transmission to either the optical fiber 64 that is the active transmission line or the optical fiber 65 that is the standby transmission line in accordance with the switching instruction signal output from the switching control unit 162. Select. The transmission line switching unit 163 transmits the wavelength-multiplexed signal light for transmission to the optical fiber selected by the switching control unit 153 (that is, the optical fiber 64 that is the active transmission line or the optical fiber 65 that is the standby transmission line). Multiplex signal light is transmitted.

  The flow of upstream signal light received from the optical fiber 64 and the optical fiber 65 in the master station device 10 is the same as that in the first and second embodiments. Further, the switching process at the time of redundancy is the same as in the first and second embodiments.

<< 4-3 >> Effect As described above, in the wavelength division multiplexing optical communication system 4 according to the fourth embodiment, the wavelength division multiplexed signal light multiplexed by the slave station apparatus (# 1) 4101 is transmitted to the master station apparatus. 10 and is not transmitted to the optical fiber 66 and the optical fiber 67 on the side of the slave station devices (# 2 to #N) on and after the second stage. Further, the wavelength division multiplexing optical communication system 4 employs a chain network and does not perform communication in both directions such as the first direction D1 and the second direction D2, unlike a ring network. Therefore, the wavelength division multiplexing optical communication system 4 can be configured only with an optical filter having a simple configuration, and expensive optical devices can be reduced, which is effective in reducing the network cost.

  For example, in the third embodiment, an optical multiplexing / demultiplexing function is arranged inside the slave station device, and a configuration independent of the optical fiber is adopted. As described above, in the third embodiment, compared to the fourth embodiment, the optical fiber shared with the other slave station apparatuses (# 1 to #N) is highly independent and connected only with a passive optical device. It can be said that the reliability is high. In contrast, in the fourth embodiment, the optical devices in the slave station devices (# 1 to #N) are integrated by directly connecting the active transmission line switch 163 to the optical fibers 64 and 65 that are transmission lines. To reduce costs. A passive optical device is a passive optical device that does not require an electrically operated component such as an optical coupler.

  The first to third embodiments employ the “1 + 1 redundant configuration”, but the fourth embodiment employs the “1: 1 redundant configuration”, and the transmission line used is one transmission line. Therefore, management of the maintenance person is easy. Here, the “1 + 1 redundant configuration” includes an operation transmission line and a preparation transmission line, and always transmits a service signal to the operation transmission line and the preparation transmission line (transmits in parallel). Say the composition.

  Except for the above, the fourth embodiment is the same as the third embodiment.

<< 5 >> Embodiment 5
<< 5-1 >> Configuration FIG. 13 is a configuration diagram schematically showing a wavelength division multiplexing optical communication system 5 according to Embodiment 5 of the present invention. In FIG. 13, the same reference numerals as those shown in FIG. 1 are given to the same or corresponding elements as those shown in FIG. The wavelength division multiplexing optical communication system 5 according to the fifth embodiment includes a master station device 50 and a slave station instead of the master station device 10 and slave station devices (# 1 to #N) 1101,. .., 5901 are different from the wavelength division multiplexing optical communication system 1 according to the first embodiment.

  The wavelength division multiplexing optical communication system 5 includes a master station device 50, a plurality of slave station devices (# 1 to #N) 5101, ..., 5901, and a plurality of slave stations from the first input / output terminal 41 of the master station device 50. Ring-type master station device 50 and a plurality of slave station devices (# 1 to #N) returning to the second input / output terminal 42 of the master station device 50 via the devices (# 1 to #N) 5101,. 5101,..., 5901 are connected, and wavelength multiplexed signal light including signal light of one wavelength or more is transmitted in the first direction D1 (operation system) and the second direction D2 (preparation system). One optical fiber 61, 62, 63 as a transmission line is provided.

  The master station device 50 includes a plurality of optical transceivers 51_1 to 51_m that respectively transmit and receive signal light M1_1,..., M9_n, a multiplexer / demultiplexer 52, a transmission / reception optical amplifier 53, and an optical branching and coupling element 54 that is a passive element. have. The plurality of optical transmitters / receivers 51_1 to 51_m and the multiplexer / demultiplexer 52 constitute a “master station transmitter / receiver” that can transmit and receive wavelength multiplexed signal light. The transmission / reception optical amplifier 53 is selected according to transmission conditions, and can be omitted when amplification is not necessary. When the transmission / reception optical amplifier 53 is omitted, the multiplexer / demultiplexer 52 and the transmission / reception optical amplifier 53 are connected by a transmission path.

  The slave station device (# 1) 5101 includes a plurality of optical transceivers 171_1 to 171_n that respectively transmit and receive a plurality of signal lights S1_1 to S1_n, a multiplexer / demultiplexer 172, a transmission / reception switch 173, and a switching control unit (alarm). Monitor unit) 174 and a group demultiplexing unit 175. The plurality of optical transceivers 171_1 to 171_n and the multiplexer / demultiplexer 172 constitute a “slave station transmission / reception unit” (that is, a slave station transmission unit and a slave station reception unit) for transmitting and receiving wavelength multiplexed signal light.

  The slave station device (#N) 5901 includes a plurality of optical transceivers 971_1 to 971_n that respectively transmit and receive a plurality of signal lights S1_1 to S1_n, a multiplexer / demultiplexer 972, a transmission / reception switch 973, and a switching control unit (alarm). Monitor unit) 974 and a group multiplexing / demultiplexing unit 975. The plurality of optical transceivers 971_1 to 971_n and the multiplexer / demultiplexer 972 constitute a “slave station transmission / reception unit” (that is, a slave station transmission unit and a slave station reception unit) for transmitting and receiving wavelength multiplexed signal light.

  The slave station devices (# 1 to #N) 5101,..., 5901 have the same configuration and function as each other, but the wavelength of the signal light handled by the slave station devices (# 1 to #N) 5101,. Wavelength groups) are different from each other. As shown in FIG. 2, in the fifth embodiment, a plurality of slave station devices are used so that wavelengths included in a wavelength group assigned in advance to the plurality of slave station devices (# 1 to #N) do not overlap each other. (# 1 to #N) are configured. Further, as shown in FIG. 3 to FIG. 5, the wavelengths included in the first wavelength group for the slave station transmission signal light and the slave station received signal light in each of the plurality of slave station devices (# 1 to #N). The plurality of slave station devices (# 1 to #N) are configured so that the wavelengths included in the second wavelength group for use do not overlap each other.

<< 5-2 >> Operation Next, operations of the master station device 50 and the plurality of slave station devices (# 1 to #N) 5101,..., 5901 of the wavelength division multiplexing optical communication system 5 according to the fifth embodiment will be described. Since the operations of the slave station devices (# 1 to #N) 5101,..., 5901 are similar to each other, the operation of the slave station device (# 1) 5101 will be described as a representative example.

  First, the downstream signal light transmitted from the master station device 50 and directed to the slave station device (# 1) 5101 through the optical fiber will be described. The signal lights M1_1,..., M9_n having a plurality of wavelengths output from the optical transceivers 51_1 to 51_m of the master station device 50 are multiplexed by the multiplexer / demultiplexer 52. The multiplexer / demultiplexer 52 uses a wide-band arrayed waveguide grating or the like, processes all signal light having a wavelength for transmission in the master station device 50, and slave station devices (# 1 to # 1). #N) It is possible to process all the signal lights having wavelengths for reception transmitted from 5101 to 5901 at once. The arrayed waveguide grating is a bidirectional optical device, and the multiplexer / demultiplexer 52 can simultaneously perform multiplexing and demultiplexing.

  The multiplexer / demultiplexer 52 in the fifth embodiment is different from the multiplexers 12 and 22 in the first to fourth embodiments in the number of wavelengths of signal light to be handled (the number of wavelengths included in the wavelength group). Is different. The multiplexer / demultiplexer 52 according to the fifth embodiment can handle all the signal lights having the wavelength arrangements as shown in FIGS. 3, 4, and 5.

  In the first to fourth embodiments, the multiplexer 12 and the demultiplexer 22 are separate components. In the master station device 10, optical branching is performed from the multiplexer 12 via the transmission optical amplifier 13. Two transmission paths (optical fibers) including a transmission path to the coupling element 31 and a transmission path from the optical branching and coupling element 31 to the duplexer 22 via the reception optical amplifier 23 are provided. In other words, one transmission path (optical fiber) is used for each of transmission and reception in the master station device 10, and one-fiber bidirectional optical transmission is not used in the master station device 10. On the other hand, in the fifth embodiment, the multiplexer / demultiplexer 52 is connected to the optical branching and coupling element 54 via the transmission / reception optical amplifier 53 through a single transmission line (optical fiber). 1-fiber bidirectional optical transmission is utilized. Therefore, according to the master station device 50 in the fifth embodiment, it is possible to reduce the number of components compared to the master station device 10 in the first to fourth embodiments, thereby reducing the cost and the failure rate. Can be achieved.

  The wavelength multiplexed signal light generated by combining the plurality of signal lights by the multiplexer / demultiplexer 52 is optically amplified by the transmission / reception optical amplifier 53 and then transmitted to the optical branching and coupling element 54. The optical branching and coupling element 54 includes a 1 × 2 port 3 dB optical coupler having ports 54 a, 54 b and 54 c. The signal light for transmission, which is the wavelength multiplexed signal light input to the port 54a of the optical branching and coupling element 54, is transmitted to the optical fiber 61 through the port 54c and the first input / output terminal 41, and the port 54d and the second optical signal. It is transmitted to the optical fiber 62 through the input / output terminal 42.

  In the slave station device (# 1) 5101, the signal light for transmission which is the wavelength multiplexed signal light transmitted in the first direction D1 through the optical fiber 61 and the optical fibers 62 and 63 are transmitted in the second direction D2. The signal light for transmission which is the wavelength multiplexed signal light is received by the group multiplexing / demultiplexing unit 175.

  In the slave station device (#N) 5901, the transmission signal light, which is the wavelength multiplexed signal light transmitted through the optical fiber 61 in the first direction D1, and the wavelength multiplexed signal transmitted through the optical fiber 62 in the second direction D2. The signal light for transmission which is signal light is received by the group multiplexing / demultiplexing unit 975.

  The slave station devices (# 1 to #N) 5101,..., 5901 operate in the same manner, but the wavelength (wavelength group) of signal light handled by the slave station devices (# 1 to #N) 5101,. Are different from each other.

  FIG. 14 is a diagram illustrating an example of an internal configuration of the group multiplexing / demultiplexing unit 175 illustrated in FIG. The group multiplexing / demultiplexing unit 175 demultiplexes or multiplexes the signal light of the wavelength group for the slave station device (# 1) 5101 from the transmission signal light that is the received wavelength multiplexed signal light. As illustrated in FIG. 14, the group multiplexing / demultiplexing unit 175 includes an optical bandpass filter 175a disposed on the optical fiber 61 side and an optical bandpass filter 175b disposed on the optical fiber 63 side. The wavelength group of downstream signal light extracted by the optical bandpass filter 175a, the wavelength group of upstream signal light transmitted through the optical bandpass filter 175a, and the wavelength group of downstream signal light extracted by the optical bandpass filter 175b The wavelength group of the upstream signal light transmitted through the optical bandpass filter 175a is the same wavelength group. The configuration of group multiplexing / demultiplexing unit 175 in the fifth embodiment can be simplified as compared with the configuration of group multiplexing / demultiplexing unit 131 (FIG. 1) in the first embodiment.

  The wavelength group signal light demultiplexed by the group multiplexing / demultiplexing unit 175 is transmitted to the switching control unit 174 and the transmission / reception switch 173. The switching control unit 174 outputs a switching instruction signal according to the signal level of the signal light of the wavelength group demultiplexed by the group multiplexing / demultiplexing unit 175. The process of the switching control unit 174 is the same as the process of the switching control unit 132 in the first embodiment. The transmission / reception switch 173 selects the wavelength group of the received signal light in accordance with the switching instruction signal from the switching control unit 174. The signal lights S1_1 to S1_n transmitted and demultiplexed from the transmission / reception switch 173 to the multiplexer / demultiplexer 172 are received by the optical transceivers 171_1 to 171_n.

  Next, the upstream signal light in slave station apparatus (# 1) 5101 will be described. The transmission signal as the user signal provided from the slave station side downstream apparatus is input to the optical transceivers 171_1 to 171_n of the slave station apparatus (# 1) 5101, and the specific wavelength for wavelength multiplexing by the optical transceivers 171_1 to 171_n. After being converted into (wavelength group) signal light, it is output to the multiplexer / demultiplexer 172.

  The multiplexer / demultiplexer 172 receives a plurality of signal lights S1_1 to S1_n having different wavelengths from the optical transceivers 171_1 to 171_n, combines them, and outputs them to the transmission / reception switch 173.

  The transmission / reception switch 173 transmits the wavelength multiplexed signal light output from the multiplexer / demultiplexer 172 via the group multiplexing / demultiplexing unit 175 in accordance with the switching instruction signal output from the switching control unit 174. 2 direction D2) or optical fiber 63 (first direction D1).

  Each of the slave station devices (# 1 to #N) 5101,..., 5901 switches the transmission signal so that the same transmission path as the transmission path of the received signal is used. For example, when the slave station device (# 1) 5101 receives downlink signal light from the master station device 50 through the optical fiber 61 in the first direction D1, the uplink output from the slave station device (# 1) 5101 The signal light is transmitted to the master station device 50 through the optical fiber 61 in the second direction D2.

  Next, the operation of the master station device 50 that has received the upstream signal light received from the slave station device via the optical fiber 61 and the upstream signal light received from the slave station device via the optical fibers 63 and 62 will be described. The master station device 50 converts the wavelength multiplexed signal light output from the slave station devices (# 1 to #N) 5101,..., 5901 transmitted in the first direction D1 and the second direction D2 into optical branching and coupling elements. 54.

  In the optical branching and coupling element 54, the wavelength multiplexed signal light provided from the optical fiber 61 and the wavelength multiplexed signal light provided from the optical fiber 62 are combined, and the wavelength multiplexed signal light generated by the combination is sent to the transmission / reception optical amplifier 53. Output.

  The transmission / reception optical amplifier 53 optically amplifies the received wavelength multiplexed signal light and transmits the optically amplified wavelength multiplexed signal light to the multiplexer / demultiplexer 52.

  The multiplexer / demultiplexer 52 demultiplexes the received wavelength multiplexed signal light for each wavelength, and transmits a plurality of signal lights M1_1,..., M9_n obtained by the demultiplexing to the plurality of optical transceivers 51_1 to 51_m. . The optical transceivers 51_1 to 51_m transmit a signal based on the received optical signal to the connected master station side downstream device.

  The redundancy switching process is the same as the process in the first embodiment.

<< 5-3 >> Effect As described above, in the fifth embodiment, the multiplexer 12 and the duplexer 22 which are the two components in the first embodiment are combined into one component. Since the multiplexer 52 and the duplexer 122 and the duplexer 122 in the first embodiment are the duplexer 172 as one component, the cost can be reduced.

  In the fifth embodiment, the number of optical switches that are active components is reduced (there is one optical switch as an active component for each slave station device), so that the failure occurrence rate And the reliability of the system can be improved.

  The optical element having a multiplexing / demultiplexing function obtained by integrating the multiplexing function and the demultiplexing function in the fifth embodiment can be applied to the second to fourth embodiments. In other words, the master station device 10 in the first to fourth embodiments can be replaced with the master station device 50 in the fifth embodiment. Also, the slave station transmitters and slave station receivers in the slave station devices (# 1 to #N) in the first to fourth embodiments are connected to the slave station devices in the slave station devices (# 1 to #N) in the fifth embodiment. It is possible to replace it with a part.

  In the wavelength multiplexing optical communication systems 1 to 5 according to the first to fifth embodiments, the master station device 10 or 50 is applied to the BBU, and the plurality of slave station devices (# 1 to #N) are respectively applied to the plurality of RRHs. This is applicable to MFH. In the wavelength division multiplexing optical communication systems 1 to 5, in the ring network and the chain network, the master station devices 10 and 50 are provided with the optical branching and coupling elements composed of passive optical couplers, and only on the slave station devices (# 1 to #N) side. Switch over. In the slave station devices (# 1 to #N) applied to the MFH, there is no transmission / reception of signals between the slave station devices (# 1 to #N), and the master station device 10 or 50 and the slave station device (# 1). ˜ # N) only signals are transmitted and received. In this way, transmission / reception of wavelength multiplexed signal light between the master station device 10 or 50 and the slave station devices (# 1 to #N) is controlled by the switching operation of only the slave station devices (# 1 to #N). be able to.

  1-5 wavelength multiplexing optical communication system, 10, 50 master station device, 11_1-11_m optical transmitter, 21_1-21_m optical receiver, 12 multiplexer, 13 transmitting optical amplifier, 22 demultiplexer, 23 receiving optical amplifier, 31, 54 Optical branching and coupling elements, 31a to 31d First to fourth ports, 41 First input / output terminal, 42 Second input / output terminal, 51_1 to 51_m Optical transceiver, 52 Multiplex / demultiplexer, 53 Transmission / reception optical amplifiers, 54a, 54c, 54d, first, second and third ports, 61-63 optical fiber (transmission path), 64, 66 optical fiber (first transmission path), 65, 67 optical fiber (first 2), 111_1 to 111_n, 911_1 to 911_n optical transmitter, 112,912 demultiplexer, 113,913 transmission switch, 121_1 121_n, 921_1 to 921_n optical receivers, 122,922 multiplexers, 123,923 reception switchers, 131,931 group multiplexing / demultiplexing units, 131a, 131b 1 × 2 port optical couplers, 131c demultiplexing optical bandpass filters 131d multiplexed optical bandpass filter, 131e multiplexed optical bandpass filter, 131f demultiplexed optical bandpass filter, 132,932 switching control unit (alarm monitor unit), 141, 151, 941, 951 optical coupling unit, 142, 942 for transmission / reception Switching unit, 143,943 Switching control unit (alarm monitoring unit), 144,944 Wavelength group filter unit, 154,954 Optical branching coupler, 155,955 Optical branching coupler, 162,962 Switching control unit (alarm monitoring unit) 163,963 Transmission path switcher, 164 64 optical multiplexing / demultiplexing unit, 171_1 to 171_n, 971_1 to 971_n optical transmitter / receiver, 172,972 multiplexer / demultiplexer, 173,973 transmission / reception switch, 174,974 switching control unit (alarm monitoring unit), 175,975 group coupling Demultiplexing unit, 1101 to 1901, 2101 to 2901, 3101 to 3901, 4101 to 4901, 5101 to 5901 Slave station devices, D1 first direction, D2 second direction.

Claims (13)

A master station device;
A plurality of slave station devices;
The master station device and the plurality of slave station devices are connected in a ring shape returning from the master station device to the master station device via the plurality of slave station devices, and wavelength multiplexed signal light is transmitted in the first direction and the first A one-core bidirectional transmission line that is transmitted in a second direction that is the opposite direction of the one direction,
Each of the plurality of slave station devices is
A slave station transmission unit that transmits a slave station transmission signal light that is a signal light of a first wavelength group among the wavelength groups previously assigned to each of the plurality of slave station devices;
A slave station receiver for receiving slave station received signal light which is signal light of the second wavelength group of the wavelength group;
Of the parent station transmission signal light transmitted from the parent station device to the transmission path, a part of the first parent station transmission signal light transmitted in the first direction and the second direction transmission are transmitted. A portion of the second master station transmission signal light that is demultiplexed and extracted as a first reception signal light and a second reception signal light, and the slave station transmission signal light is input to the transmission path A multiplexing / demultiplexing part;
A switching control unit that outputs a switching instruction signal based on levels of the first master station transmission signal light and the second master station transmission signal light;
Based on the switching instruction signal, either the first reception signal light or the second reception signal light is provided to the slave station reception unit as the slave station reception signal light, and based on the switching instruction signal A switching unit that switches a transmission direction in which the slave station transmission signal light input to the transmission path is transmitted through the transmission path to either the first direction or the second direction;
The plurality of slave station devices are configured so that wavelengths included in the wavelength group assigned in advance to the plurality of slave station devices do not overlap each other,
In each of the plurality of slave station devices, the plurality of slave station devices are configured such that the wavelength included in the first wavelength group and the wavelength included in the second wavelength group do not overlap each other. A wavelength-division multiplexed optical communication system. The master station device is
A first input / output terminal and a second input / output terminal connected to the transmission line;
An optical branching and coupling element which is a passive element having first, second, third and fourth ports;
A master station transmission unit for transmitting the master station transmission signal light to the first port;
A master station receiver that receives the slave station transmission signal light output from the second port;
The master station transmission signal light input from the first port is branched and passes through the third port and the first input / output terminal in the first direction in the transmission path in the first direction. Transmitted as transmission signal light and transmitted as the second master station transmission signal light in the second direction in the transmission path through the fourth port and the second input / output terminal. The slave station transmission signal light transmitted in the second direction input to the third port via the output terminal and the input to the fourth port via the second input / output terminal 2. The wavelength division multiplexing optical communication according to claim 1, wherein the slave station transmission signal light transmitted in the first direction is combined and transmitted from the second port to the master station reception unit. system. The master station device is
A first input / output terminal and a second input / output terminal connected to the transmission line;
An optical branching and coupling element being a passive element having first, second and third ports;
A master station transmission / reception unit that transmits the master station transmission signal light to the first port and receives the slave station transmission signal light output from the first port;
The master station transmission signal light input from the first port is branched and passes through the second port and the first input / output terminal in the first direction in the transmission path in the first direction. Transmitted as transmission signal light and transmitted as the second master station transmission signal light in the second direction in the transmission path through the third port and the second input / output terminal, The slave station transmission signal light transmitted in the second direction input to the second port via the output terminal and the third port input to the third port via the second input / output terminal 2. The wavelength division multiplexing optical communication according to claim 1, wherein the slave station transmission signal light transmitted in the first direction is combined and transmitted from the first port to the master station transmission / reception unit. system.   4. The wavelength division multiplexing optical communication system according to claim 3, further comprising a slave station transmission / reception unit including the slave station transmission unit and the slave station reception unit. The switching unit is
A receiving switch for outputting either the first received signal light or the second received signal light as the slave station received signal light to the slave station receiver;
A transmission switch for switching a transmission direction in which the slave station transmission signal light input to the transmission path is transmitted in the transmission path to either the first direction or the second direction. The wavelength division multiplexing optical communication system according to any one of claims 1 to 4. A master station device;
A plurality of slave station devices;
The master station apparatus and the plurality of slave station apparatuses are connected in a chain type, and the wavelength-division multiplexed signal light is in the downstream direction from the master station apparatus to the plurality of slave station apparatuses and in the uplink direction opposite to the downlink direction A one-core bidirectional first transmission line transmitted to
One-core bi-directional transmission in which the master station device and the plurality of slave station devices are connected in a chain form, and wavelength multiplexed signal light is transmitted from the master station device to the plurality of slave station devices in the downlink and uplink directions And a second transmission line of
Each of the plurality of slave station devices is
A slave station transmission unit that transmits a slave station transmission signal light that is a signal light of a first wavelength group among the wavelength groups previously assigned to each of the plurality of slave station devices;
A slave station receiver for receiving slave station received signal light which is signal light of the second wavelength group of the wavelength group;
A part of the master station transmission signal light transmitted from the master station device to the first transmission path is demultiplexed and extracted as a first reception signal light, and the slave station transmission signal light is extracted from the first transmission signal light. A function of inputting to a transmission line; and a part of the master station transmission signal light transmitted from the master station apparatus to the second transmission path is demultiplexed and extracted as a second reception signal light; A group multiplexing / demultiplexing unit having a function of inputting station transmission signal light to the second transmission path;
A switching control unit that outputs a switching instruction signal based on at least one of a level of the master station transmission signal light in the first transmission path and a level of the master station transmission signal light in the second transmission path;
Based on the switching instruction signal, either the first reception signal light or the second reception signal light is provided to the slave station reception unit as the slave station reception signal light, and based on the switching instruction signal And a switching unit that switches the transmission path to which the slave station transmission signal light is input to either the first transmission path or the second transmission path,
The plurality of slave station devices are configured so that wavelengths included in the wavelength group assigned in advance to the plurality of slave station devices do not overlap each other,
In each of the plurality of slave station devices, the plurality of slave station devices are configured such that the wavelength included in the first wavelength group and the wavelength included in the second wavelength group do not overlap each other. A wavelength-division multiplexed optical communication system. The master station device is
A first input / output terminal connected to the first transmission line;
A second input / output terminal connected to the second transmission line;
An optical branching and coupling element which is a passive element having first, second, third and fourth ports;
A master station transmission unit for transmitting the master station transmission signal light to the first port;
A master station receiver that receives the slave station transmission signal light output from the second port;
The master station transmission signal light input from the first port is branched and transmitted to the first transmission path through the third port and the first input / output terminal, and the fourth port and Transmitted to the second transmission line through the second input / output terminal;
The slave station transmission signal light input to the third port via the first input / output terminal or the slave station transmission signal light input to the fourth port via the second input / output terminal Is transmitted from the second port to the master station receiver. 7. The wavelength division multiplexing optical communication system according to claim 6, wherein: The master station device is
A first input / output terminal connected to the first transmission line;
A second input / output terminal connected to the second transmission line;
An optical branching and coupling element being a passive element having first, second and third ports;
A master station transmission / reception unit that transmits the master station transmission signal light to the first port and receives the slave station transmission signal light output from the first port;
The master station transmission signal light input from the first port is branched and transmitted to the first transmission path through the second port and the first input / output terminal, and the third port. And the second transmission signal light transmitted to the second transmission line through the second input / output terminal and input to the second port through the first input / output terminal. The wavelength according to claim 6, wherein the slave station transmission signal light input to the third port via an output terminal is transmitted from the first port to the master station transmission / reception unit. Multiple optical communication system.   9. The wavelength division multiplexing optical communication system according to claim 8, further comprising a slave station transmission / reception unit including the slave station transmission unit and the slave station reception unit.   Of the wavelength group pre-assigned to each of the plurality of slave station devices, the signal light of the first wavelength group used as the slave station transmission signal light and the slave station reception signal light 10. The wavelength according to claim 1, wherein the signal light of the second wavelength group is arranged on a short wavelength side and a long wavelength side across a predetermined wavelength band. Multiple optical communication system.   Of the wavelength group pre-assigned to each of the plurality of slave station devices, the signal light of the first wavelength group used as the slave station transmission signal light and the slave station reception signal light The wavelength division multiplexing optical communication system according to any one of claims 1 to 9, wherein the signal light of the second wavelength group is alternately arranged in order from the short wavelength side.   The plurality of first wavelength groups for the plurality of slave station devices and the plurality of second wavelength groups for the plurality of slave station devices are on the short wavelength side across a predetermined wavelength band. The wavelength division multiplexing optical communication system according to claim 1, wherein the wavelength division multiplexing optical communication system is arranged on a long wavelength side.   13. Each of the plurality of slave station devices receives a predetermined supervisory control signal light and generates the switching instruction signal based on a level of the supervisory control signal light. The wavelength division multiplexing optical communication system according to any one of the above.

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