JP2013070204A - Optical transceiver, optical transmission level setting method, and setting program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transceiver etc. capable of easily adjusting optical power on a transmission side, thereby reducing power consumption and extending the life of an apparatus.SOLUTION: In an optical transceiver 10, an optical transmission unit 10a comprises a laser diode element 12 for emitting a transmission optical signal and a laser diode driver 11 which converts a transmission data signal to an output current for driving the laser diode element to perform the light emission, and an optical reception unit 10b comprises a photodiode element 13 which receives a reception optical signal and generates a reception optical current and a transimpedance amplifier 14 for amplification, voltage conversion, and output of the reception optical current. The laser diode driver 11 inputs to the laser diode element the output current obtained by multiplying the reception optical current by a predetermined ratio.

Description

  The present invention relates to an optical transceiver, an optical transmission level setting method, and a setting program, and more particularly to an optical transceiver that can appropriately set an optical transmission level in order to reduce power consumption and extend the life of an apparatus.

  The optical transceiver is detachably mounted on the optical communication apparatus main body, and operates by receiving a clock signal from the apparatus main body. Laser diodes and photodiodes built in the optical transceiver operate based on the supplied clock signal, and send and receive data to and from other networks via optical cables. To the host device.

  There are the following technical documents related to this. Among them, Patent Document 1 describes an optical transceiver for a subscriber apparatus in which the intensity of the received optical signal is detected on the subscriber apparatus side and the intensity of the transmitted optical signal toward the central apparatus is adjusted accordingly. Has been. Similarly to this, Patent Document 2 describes an optical communication system in which the intensity of a transmission optical signal is adjusted on the subscriber apparatus side.

  Patent Document 3 describes a PON system in which the delay time is corrected on both the subscriber device side and the subscriber accommodation device side. Patent Document 4 describes an optical transceiver capable of easily measuring a transmission distance in optical communication. Patent Document 5 describes an output control device that controls its own transmission output in accordance with the distance from the other party's transceiver by airborne infrared communication. Patent Document 6 describes an optical communication system in which control information is included in specific bits and transmitted.

JP 2005-318629 A JP 2010-161454 A JP 2000-295266 A JP 2008-252750 A Japanese Patent Application Laid-Open No. 09-083443 Japanese Patent Laid-Open No. 11-308177

  Particularly in recent years, the scale of optical communication networks has increased rapidly both in the number of subscribers and in the total amount of data transmitted. In particular, recently, the supply of electric power has been tightened nationwide, and therefore, there is an urgent need to reduce power consumption even in optical communication networks. Of course, as long as the optical communication network is operated, the cost reduction is always required for the communication carrier, and the network down must never be down.

  In view of the circumstances as described above, reduction of power consumption, long life and high reliability of the device are particularly desired for an optical transceiver that is detachably mounted on the optical communication device body. Especially in optical transceivers, if the transmitter's optical power emitted by a laser diode is excessive, power consumption is clearly wasted, and a laser diode that emits excessive optical power and a photodiode that receives excessive optical power. Both of them will accelerate the deterioration of parts. On the other hand, if the optical power is too low, errors occur frequently and data cannot be transmitted normally.

  Therefore, in the optical transceiver, it is necessary to adjust the optical power on the transmission side so that the optical power range is optimal for light reception by the photodiode on the reception side. However, in a normal optical communication apparatus, a plurality of optical transceivers are mounted, each of which is connected to an optical cable having a different transmission length. Then, the optical powers of all the optical transceivers mounted on the same optical communication apparatus are adjusted in accordance with the optical cable having the largest transmission loss, that is, the longest transmission distance.

  This has a high risk of excessive optical power for an optical transceiver connected to another optical cable mounted in the same optical communication apparatus (having a shorter transmission distance, that is, having a smaller transmission loss). In other words, it is desirable to adjust the optical power of each optical transceiver so that it is optimal for each optical cable having a different transmission length (transmission loss). However, in an ordinary optical communication device, the operation becomes complicated. Currently, such adjustments are rarely made.

  Techniques that can solve this problem are not described in the aforementioned Patent Documents 1 to 6. Each of Patent Documents 1 and 2 is a technique of adjusting the intensity of a transmitted optical signal “on the subscriber device side”, but the central office in which a large number of optical transceivers are densely mounted for many subscribers. In particular, reduction of power consumption and long life and high reliability of the apparatus are desired on the optical communication apparatus main body side, and the techniques of Patent Documents 1 and 2 cannot exhibit the effect on the central office side.

  The remaining Patent Documents 3 to 6 do not describe a technique for adjusting the intensity of a transmission optical signal by optical fiber communication in the first place. Of these, only the patent document 4 describes the technology regarding the optical transceiver, which is also for the purpose of “measurement of transmission distance”, and adjusts the intensity of the transmitted optical signal. It is not a thing.

  An object of the present invention is to provide an optical transceiver, an optical transmission level setting method, and a setting program that can easily adjust the optical power on the transmission side, thereby reducing power consumption and extending the life of the apparatus. There is to do.

  In order to achieve the above object, an optical transceiver according to the present invention includes an optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal, and transmits the transmission optical signal to an optical cable. An optical transceiver comprising an optical receiver that converts a received optical signal sent from a network into a received data signal and outputs the received data signal to a station-side host device, wherein the optical transmitter emits a transmitted optical signal, and A laser diode driver that converts a transmission data signal into an output current for driving the laser diode element to emit light and inputs the current to the laser diode element, and a photoreceiver that receives the received optical signal and generates a received photocurrent A diode element and a transimpedance that amplifies and converts the received photocurrent and converts it into a received data signal. Together and a dance amplifier, laser diode driver, characterized in that inputting an output current obtained by multiplying the pre-given ratio to the received photocurrent to the laser diode element.

  In order to achieve the above object, an optical transmission level setting method according to the present invention includes an optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends the transmission optical signal to an optical cable, and an optical cable. In the optical communication system, each of the station side and the terminal side includes an optical transceiver including an optical receiving unit that converts a received optical signal sent from another network into a received data signal and outputs the received data signal to the upper device on the station side. In one of the optical transceivers of the station side and the terminal side, the transmission data signal is converted into and inputted to an output current that causes the first laser diode driver of the optical transmission unit to drive the first laser diode element to emit light. Light is emitted and sent to the optical cable, and the optical signal received from the optical cable is transmitted to the photodiode by the other optical transceiver on the station side and terminal side. The child receives light and generates a received photocurrent, which is input to the second laser diode driver, and the second laser diode driver is given in advance to the received photocurrent by the other optical transceiver on the station side and the terminal side. The output current multiplied by the ratio is input to the second laser diode element to emit a transmission optical signal, which is transmitted to the optical cable. The optical signal received from the optical cable by one of the optical transceivers of the station side and the terminal side. Is received by the photodiode element, and the optical power detection means detects the intensity of the received optical signal received by the optical transceiver on one of the station side and the terminal side, and displays it on the display unit.

  In order to achieve the above object, an optical transmission level setting program according to the present invention converts a transmission data signal received from a station-side host device into a transmission optical signal, enters an optical cable, and emits from the optical cable. In the optical communication system, each of the station side and the terminal side includes an optical transceiver including an optical receiving unit that converts the received optical signal into a received data signal and outputs the received data signal to the station-side host device. A computer provided with a laser diode driver to which a received optical current generated by receiving a received optical signal emitted from one of the optical transceivers and transmitted to an optical cable by the other optical transceiver of the station side and the terminal side is input In addition, a procedure for converting the received photocurrent into an input digital value, a procedure for determining whether or not the input digital value is within a predetermined numerical range, It refers to the contents of the look-up table, characterized in that to perform the steps of inputting instructions for determining an output digital value corresponding to the input digital values, and an output current corresponding to the output digital value to the laser diode element.

  As described above, the present invention is configured to input the received photocurrent output from the photodiode element of the optical receiver unit to the laser diode driver of the optical transmitter unit so that the laser diode element emits light. The optical power on the transmission side can be adjusted with only the optical transceiver on the station side and the terminal side without preparing the above. As a result, it is possible to provide an optical transceiver, an optical transmission level setting method, and a setting program that have excellent characteristics that power consumption can be reduced and the life of the apparatus can be extended.

It is explanatory drawing shown about the structure of the optical transceiver which concerns on the 1st Embodiment of this invention. It is explanatory drawing shown about an example of the more detailed structure of LDD shown in FIG. It is explanatory drawing shown about the structure of the optical communication system using the optical transceiver shown in FIG. It is a graph showing the light reception characteristic of PD element shown in FIG. 2 is a graph showing light emission characteristics of the LD element shown in FIG. 1. FIG. 3 is an explanatory diagram showing an operation of adjusting a transmission light power by measuring a value of transmission light loss in the optical communication system shown in FIG. It is explanatory drawing shown about the structure of the optical transceiver which concerns on the 2nd Embodiment of this invention. It is explanatory drawing shown about the more detailed structure of LDD shown in FIG. It is a flowchart shown about operation | movement of LDD (output determination part) shown in FIG.

(First embodiment)
Hereinafter, the structure of the 1st Embodiment of this invention is demonstrated based on attached FIGS. 1-3.
First, the basic content of the present embodiment will be described, and then more specific content will be described.
The optical transceiver 10 according to this embodiment converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable, and is sent from another network via the optical cable. The optical transceiver includes an optical receiver 10b that converts a received optical signal into a received data signal and outputs the received data signal to a higher-level device on the station side. An optical transmitter 10a of the optical transceiver 10 converts a laser diode element 12 that emits a transmission optical signal, and a laser diode driver 11 that converts a transmission data signal into an output current that drives the laser diode element to emit light and inputs the output current to the laser diode element. A photodiode element 13 that receives a received optical signal and generates a received photocurrent, and a transimpedance amplifier that amplifies and converts the received photocurrent and outputs it as a received data signal. 14. Then, the laser diode driver 11 inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element.

  Further, the laser diode driver 11 includes a switch 11c that switches which of the transmission optical signal and the reception photocurrent is input to the laser diode element 12.

  Further, the laser diode driver 11 includes a current mirror circuit 11a that inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element.

With the above configuration, the optical transceiver 10 according to the present embodiment can easily adjust the optical power on the transmission side.
Hereinafter, this will be described in more detail.

  FIG. 1 is an explanatory diagram showing the configuration of the optical transceiver 10 according to the first embodiment of the present invention. The optical transceiver 10 converts a transmission data signal into a transmission optical signal and enters it toward the optical cable 20, and converts a reception optical signal emitted from the optical cable 20 into a reception data signal and converts it into a station-side host device. And an optical receiving unit 10b for outputting to the receiver. Furthermore, the display part 17 which displays the intensity | strength of a received optical signal, and the adjustment part 18 which adjusts the intensity | strength of a transmitted optical signal are provided.

  The optical transmission unit 10a includes a laser diode driver 11 (hereinafter referred to as LDD 11) and a laser diode element 12 (hereinafter referred to as LD element 12). The LDD 11 receives an input of a transmission data signal and generates an output current that drives the LD element 12 to emit light in accordance with the input. At that time, the output current from the LDD 11 is adjusted according to the operation from the adjustment unit 18. The LD element 12 emits light by the output current from the LDD 11 and the emitted light is incident on the optical cable 20 as a transmission optical signal.

  The optical receiver 10 b includes a photodiode element 13 (hereinafter referred to as PD element 13), a transimpedance amplifier 14 (hereinafter referred to as TIA 14), and an optical power detection means 16. The PD element 13 receives a received optical signal emitted from the optical cable 20 and generates a received photocurrent.

  The TIA 14 amplifies and converts the received photocurrent generated by the PD element 13 and outputs it as a received data signal. The optical power detection means 16 detects the value of the optical power received by the PD element 13 from the output signal from the TIA 14 and displays it on the display unit 17.

  FIG. 2 is an explanatory diagram showing an example of a more detailed configuration of the LDD 11 shown in FIG. The LDD 11 includes a current mirror circuit 11a. The current mirror circuit 11a has a mirror ratio of 1: N, and assuming that the received photocurrent output from the PD element 13 is Ir1, the current mirror circuit 11a outputs a current If1 expressed by the following formula 1 to the LD element 12. To do.

  Although FIG. 2 shows a current mirror circuit having a very basic configuration, various configurations for suppressing deterioration of characteristics due to the Early effect or the like are actually known. Specifically, for example, Japanese Patent Application Laid-Open No. 2011-059840 discloses an example.

  Also, the LDD 11 includes an optical signal generator 11b that generates an output current for driving the LD element 12 to emit light according to a transmission data signal input from the host device, an output current from the optical signal generator 11b, and a current mirror circuit. A switch 11c for switching which of the output currents from 11a is input to the LD element 12 is also included.

  The switch 11c can be operated from outside the housing of the optical transceiver 10. Alternatively, the switch 11c is not provided, and both the output current from the optical signal generator 11b and the output current from the current mirror circuit 11a can be input to the LD element 12.

  FIG. 3 is an explanatory diagram showing a configuration of the optical communication system 100 using the optical transceiver 10 shown in FIG. The optical communication system 100 is configured by connecting a communication station side communication device 110 and a plurality of terminal side communication devices 121, 121, and 123 through optical cables 131, 132, and 133, respectively. Although three terminal side communication apparatuses 121 to 123 are shown in FIG. 3, the number of terminal side communication apparatuses is not limited.

  In the communication station side communication device 110, three optical transceivers 10 shown in FIG. These are referred to as optical transceivers 101-103. Further, one optical transceiver 10 shown in FIG. 1 is mounted on each of the terminal side communication devices 121 to 123. These are referred to as optical transceivers 104-106.

  The optical transceivers 101 and 104 (terminal side communication device 121) are connected by an optical cable 131, the optical transceivers 102 and 105 (terminal side communication device 122) are connected by an optical cable 132, and the optical transceivers 103 and 106 (terminal side) are connected. The communication device 123) is connected by an optical cable 133.

  Here, the cable distance of the optical cable 131 (between the optical transceivers 101 and 104) is d1, and the transmission optical loss is Ploss1. Further, the cable distance of the optical cable 132 (between the optical transceivers 102 and 105) is d2, and the transmission optical loss is Ploss2. The cable distance of the optical cable 133 (between the optical transceivers 103 and 106) is d3, and the transmission optical loss is Ploss3. Furthermore, d1> d2> d3 and Ploss1> Ploss2> Ploss3.

  FIG. 4 is a graph showing the light receiving characteristics of the PD element 13 shown in FIG. The PD element 13 outputs a received photocurrent (unit μA) that can be linearly approximated with respect to the optical power (unit dBm) of the received optical signal. If three points of the received optical power values are Pr1, Pr2, Pr3 (Pr3> Pr2> Pr1), the received photocurrents are Ir1, Ir2, Ir3 (Ir3> Ir2> Ir1), respectively.

  FIG. 5 is a graph showing the light emission characteristics of the LD element 12 shown in FIG. The LD element 12 emits light with a transmission light power (unit dBm) that can be linearly approximated with respect to the transmission photocurrent (unit μA). When three points of the value of the transmission photocurrent are If1, If2, If3 (If1> If2> If3), the transmission light powers are Pf1, Pf2, Pf3 (Pf1> Pf2> Pf3), respectively.

(Description of operation)
The operation of the optical communication system 100 described above will be described. Prior to this operation, the switch 11c is switched so that the output current from the current mirror circuit 11a is input to the LD element 12 in the optical transceiver 101 of the station side optical communication apparatus 110, and simultaneously output from the PD element 13. Switching is performed so that the received photocurrent is input to the LDD 11.

  FIG. 6 is an explanatory diagram showing an operation of adjusting the transmission optical power by measuring the value of the transmission optical loss in the optical communication system 100 shown in FIG. First, an optical signal having a transmission optical power of Pf0 is sent from the optical transceiver 104 of the terminal side optical communication apparatus 121 to the optical cable 131 (step S201). Since the transmission optical loss of the optical cable 131 is Ploss1, the optical transceiver 101 built in the station side optical communication apparatus 110 receives the received optical power of Pf0-Ploss1 (= Pr1) (step S202).

  The PD element 13 that has received the received optical power of Pr1 in the optical transceiver 101 of the station side optical communication apparatus 110 outputs the received photocurrent Ir1 corresponding to Pr1 shown in FIG. The received photocurrent Ir1 is input to the LDD 11, and the current If1 is output to the LD element 12 so that the current mirror circuit 11a (mirror ratio 1: N) in the LDD 11 is in the formula 1. The LD element 12 emits light with the transmission light power Pf1 corresponding to If1 shown in FIG. 5 (step S203).

  When the transmission optical power Pf1 is transmitted from the optical transceiver 101 of the station side optical communication apparatus 110 to the optical cable 131, the optical transceiver 104 of the terminal side optical communication apparatus 121 receives the reception optical power of Pf1-Ploss1 (step S204). The received light power received is displayed on the display unit 17 (step S205).

  With the above operation, the value of the transmission optical loss Ploss1 can be grasped by the optical power detection means 16 on the optical transceiver 104 side of the terminal side optical communication apparatus 121. More specifically, with respect to the transmitted transmission light power Pf0, the received reception light power is expressed by the following formula 2.

  As a result, the user can grasp the value of the transmission light loss Ploss1 and move the adjustment unit 18 accordingly to adjust the value of the transmission light power Pf0. This adjustment may be performed manually, or a mechanism for automatically adjusting the value of the transmission optical power Pf0 to the optimum value may be provided in the optical transceiver 10.

  This operation can be performed from either side of the optical transceiver 101 of the station side optical communication apparatus 110 and the optical transceiver 104 of the terminal side optical communication apparatus 121. Similarly, optical communication between the optical transceivers 102 and 105 via the optical cable 132 and optical communication between the optical transceivers 103 and 106 via the optical cable 133 can be performed in the same manner.

  At that time, from the relationship of Ploss1> Ploss2> Ploss3, the relationship of Pr3> Pr2> Pr1, Ir3> Ir2> Ir1 shown in FIG. 4, and the relationship of Pf1> Pf2> Pf3, If1> If2> If3 shown in FIG. When the cable distance is long and the transmission light loss is large, the transmission light power transmitted from the optical transceivers 101 to c of the communication station side communication apparatus 110 is increased. When the cable distance is short and the transmission light loss is small, the transmission light is transmitted. It can be easily adjusted to reduce the power.

(Overall operation of the first embodiment)
Next, the overall operation of the above embodiment will be described.
The optical transmission level setting method according to this embodiment includes an optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable, and is sent from another network via the optical cable. In the optical communication system provided in each of the station side and the terminal side, an optical transceiver provided with an optical receiving unit that converts the received optical signal into a received data signal and outputs the received data signal to the higher-level equipment on the station side. In one of the optical transceivers, the first laser diode driver of the optical transmission unit converts the transmission data signal into an output current that drives the first laser diode element to emit light, emits the transmission optical signal, and sends it to the optical cable. (Step S201 in FIG. 6), the other optical transceiver on the station side and the terminal side converts the received optical signal sent from the optical cable to the photo die. The light receiving element receives light and generates a received photocurrent and inputs it to the second laser diode driver (FIG. 6, step S202). The second laser diode driver is connected to the other optical transceiver on the station side and the terminal side. An output current obtained by multiplying the received photocurrent by a predetermined ratio is input to the second laser diode element, and a transmission optical signal is emitted and transmitted to the optical cable (FIG. 6, step S203). One of the optical transceivers receives the received optical signal sent from the optical cable by the photodiode element (FIG. 6, step S204), and the received optical signal received by one of the optical transceivers of the station side and the terminal side is received. The optical power detection means detects the intensity and displays it on the display unit (step S205 in FIG. 6).

Here, each of the above-described operation steps may be programmed to be executable by a computer, and may be executed by the optical transceiver 10 that directly executes each of the steps. The program may be recorded on a non-temporary recording medium, such as a DVD, a CD, or a flash memory. In this case, the program is read from the recording medium by a computer and executed.
By this operation, this embodiment has the following effects.

  In the embodiment of the present invention, the received optical power received according to the transmission optical loss is detected, and the transmitted optical power transmitted from the optical transceiver is automatically adjusted to an appropriate value according to the received optical power. Therefore, it becomes possible to reduce the power consumption of the optical transceiver itself, to deteriorate the parts, and to reduce the power consumption of the optical communication apparatus on the station side. In this case, since this operation is performed between a pair of optical transceivers connected to each other via an optical cable, the operation can be performed regardless of other optical transceivers mounted on the same station side optical communication apparatus 110.

(Second Embodiment)
The optical transceiver 210 according to the second embodiment of the present invention replaces the laser diode driver 11 of the first embodiment with the current mirror circuit 11a, and performs A / D conversion for converting the received photocurrent into an input digital value. Unit 211a, output determination unit 211b for determining an output digital value corresponding to the input digital value with reference to the contents of lookup table 211d stored in advance in the storage unit provided, and an output current corresponding to the output digital value The laser diode driver 211 is provided with a D / A converter 211c that inputs the signal to the laser diode element.

According to this configuration, in addition to the same effects as those of the first embodiment described above, the value of the received photocurrent can be further determined in detail, and various operations can be set according to the determination result.
This will be described in more detail below.

  FIG. 7 is an explanatory diagram showing the configuration of the optical transceiver 210 according to the second embodiment of the present invention. In the optical transceiver 210, compared to the optical transceiver 10 according to the first embodiment described above, the LDD 11 is replaced with another laser diode driver 211 (hereinafter referred to as an LDD 211). Since it is the same as the optical transceiver 10 according to the embodiment, it is referred to by the same name and reference number. Further, the configuration of the entire optical communication system is merely the replacement of the optical transceiver 10 with the optical transceiver 210 in the configuration of FIG.

  FIG. 8 is an explanatory diagram showing a more detailed configuration of the LDD 211 shown in FIG. The LDD 211 converts an analog signal input from the PD element 13 or the station-side host device into a digital signal, and an output current value corresponding to the digital signal output from the A / D converter 211a ( Output determining unit 211b that determines the light emission current If1), D / A converter 211c that outputs the current of the output current value determined by the output determining unit 211b, and when the output determining unit 211b determines the output current value A lookup table (LUT) that stores data to be referenced;

  The LDD 211 also includes a switch 211e for switching which analog signal of the PD element 13 and the station-side host device is input to the A / D conversion unit 211a, instead of the switch 11c in the first embodiment. ing. Here, in the normal operation, an analog signal from the station-side host device is input to the A / D conversion unit 211a. In the operation of the present invention, the analog signal from the PD element 13 is input to the A / D conversion unit 211a. Thus, the input signal is switched in advance. As in the first embodiment, the switch 211e can be omitted.

  The output determination unit 211b can be realized by operating a computer program with a microprocessor. The LUT storage unit 211d can be realized by a storage device such as a ROM or a RAM. That is, the operation of the LDD 211 can be realized as a computer program.

  The LUT stored in the LUT storage unit 211d is a digital value Dr1 output from the A / D conversion unit 211a in response to the received photocurrent Ir1, and is input to the D / A conversion unit 211c in response to the light emission current If1. Is stored in correspondence with the digital value Df1 for outputting.

  That is, depending on the data stored in the LUT storage unit 211d, the LDD 211 may output N times the received photocurrent Ir1 as the light emission current If1, similarly to the current mirror circuit 11a in the first embodiment. it can. In addition, the relationship between the reception photocurrent Ir1 and the light emission current If1 can be set to an arbitrary characteristic.

  FIG. 9 is a flowchart showing the operation of the LDD 211 (output determination unit 211b) shown in FIG. This is an operation corresponding to steps S202 to S203 in the flowchart of FIG. 6 shown for the first embodiment. The premise for performing this operation is to switch in advance so that the received photocurrent output from the PD element 13 is input to the LDD 11 as in the first embodiment. As described above, the switch 211e is switched in advance so that the analog signal from the PD element 13 is input to the A / D converter 211a.

  First, the output determination unit 211b determines whether or not there is an input of the received photocurrent Ir1 through the A / D conversion unit 211a (step S301). If there is an input of Ir1, the process proceeds to step S302. If there is no input of Ir1, an alarm is issued (step S304), and the process ends.

  Next, the output determination unit 211b compares the value of the input received photocurrent Ir1 with two values of Ir1min and Ir1max given in advance, and determines whether or not Ir1min ≦ Ir1 <Ir1max (step S302). ). Specifically, the output determination unit 211b compares Dr1min and Dr1max, which are digital values corresponding to Ir1min and Ir1max on the LUT, and Dr1min ≦ Dr1 which is a digital value corresponding to the received photocurrent Ir1. It is determined whether or not <Dr1max.

  If the value of the received photocurrent Ir1 is not in the range between Ir1min and Ir1max in step S302, an alarm is also issued (step S304) and the process is terminated. If the value of the received photocurrent Ir1 is in the range between Ir1min and Ir1max, the output determination unit 211b refers to the LUT to determine the digital value Df1 corresponding to the digital value Dr1, and uses this digital value Df1 as D / A. The data is output to the conversion unit 211c. The D / A conversion unit 211c outputs the light emission current If1 corresponding to the digital value Df1 to the LD element 12 (step S303) and ends the process.

(Overall operation of the second embodiment)
Next, the overall operation of the above embodiment will be described.
The processing in which the second laser diode driver according to the present embodiment inputs the output current to the second laser diode element (FIG. 6, steps S202 to 203), the received photocurrent is converted to the input digital value by the A / D converter. The output determination unit determines whether or not the input digital value is within a range of numerical values given in advance (FIG. 9, step S301), and the contents of the lookup table stored in advance in the provided storage unit , The output determining unit determines the output digital value corresponding to the input digital value (step S302 in FIG. 9), and the D / A converter inputs the output current corresponding to the output digital value to the laser diode element (see FIG. 9). FIG. 9 Step S303).

Here, each of the above-described operation steps may be programmed to be executable by a computer, and may be executed by the optical transceiver 210 that directly executes each of the steps. The program may be recorded on a non-temporary recording medium, such as a DVD, a CD, or a flash memory. In this case, the program is read from the recording medium by a computer and executed.
By this operation, this embodiment has the following effects.

  As a result, the same processing as in the first embodiment can be performed. Furthermore, for example, when there is an optical communication disconnection due to an optical cable disconnection or a failure of the station side optical communication apparatus, Ir1 is not input in the above-described step S301, so that an alarm can be issued in step S304. Even when the value of the received photocurrent Ir1 is not in the range between Ir1min and Ir1max given in advance, an alarm can be issued in step S304. The ranges of Ir1min and Ir1max can be set assuming a specific transmission distance, deterioration of parts, and the like.

(Extended embodiment)
Various extensions can be considered for the first and second embodiments described above without departing from the spirit of the first and second embodiments. This will be described below.

  The transmission optical loss measurement operation shown in FIGS. 6 and 9 has been described on the premise that the switch 11c (211e) of the optical transceiver 10 (210) is switched in advance.

  However, for example, a specific optical signal is transmitted as an “adjustment operation start signal” from one optical transceiver 10 (210), and the switch 11c (211e) is switched accordingly in the other optical transceiver 10 (210). If the operations shown in FIGS. 6 and 9 are performed, transmission light loss can be measured without switching each switch in advance.

  Further, in combination with this, there may be provided means for automatically adjusting the transmission power in the optical transmission unit 10a (210a) in accordance with the received optical power detected by the optical power detection means 16. That is, if these two features are added, the measurement of the received light power and the adjustment of the transmitted light power can be integrated and automated. For example, this operation may be performed by a timer in a time zone where the influence of network down is small, such as late at night.

  The operation in FIG. 9 and step S302 in the second embodiment is based on the premise that the received photocurrent is digitized and processed. However, for example, a similar process is performed using a window comparator circuit or the like. Can also be realized.

  The present invention has been described with reference to the specific embodiments shown in the drawings. However, the present invention is not limited to the embodiments shown in the drawings, and any known hitherto provided that the effects of the present invention are achieved. Even if it is a structure, it is employable.

  Regarding the embodiment described above, the main points of the new technical contents are summarized as follows. In addition, although part or all of the said embodiment is summarized as follows as a novel technique, this invention is not necessarily limited to this.

(Supplementary note 1) An optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable; and a reception optical signal sent from another network via the optical cable as reception data An optical transceiver comprising an optical receiving unit that converts the signal into a signal and outputs the signal to the station host host device,
The optical transmission unit includes a laser diode element that emits the transmission optical signal, and a laser diode driver that converts the transmission data signal into an output current that drives the laser diode element to emit light and inputs the output current to the laser diode element. ,
A photodiode element that receives the received optical signal and generates a received photocurrent; and a transimpedance amplifier that amplifies and converts the received photocurrent and outputs the received data signal as the received data signal. As well as
The optical transceiver, wherein the laser diode driver inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element.

(Supplementary note 2) The optical transceiver according to supplementary note 1, wherein the laser diode driver includes a switch for switching which of the transmission optical signal and the reception photocurrent is input to the laser diode element. .

(Supplementary note 3) The light according to supplementary note 1, wherein the laser diode driver includes a current mirror circuit that inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element. Transceiver.

(Appendix 4) The laser diode driver is
An A / D converter that converts the received photocurrent into an input digital value;
An output determination unit that determines an output digital value corresponding to the input digital value with reference to the contents of a lookup table stored in advance in a storage unit provided;
The optical transceiver according to appendix 1, further comprising: a D / A converter that inputs the output current corresponding to the output digital value to the laser diode element.

(Supplementary Note 5) An optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable, and a reception optical signal sent from another network via the optical cable as reception data In an optical communication system provided on each of the station side and the terminal side, an optical transceiver comprising an optical receiving unit that converts the signal into a signal and outputs it to the station-side host device,
In one of the optical transceivers of the station side and the terminal side, the transmission data signal is converted and input to an output current that causes the first laser diode driver of the optical transmission unit to drive the first laser diode element to emit light. Sending a transmission optical signal to the optical cable,
The other optical transceiver of the station side and the terminal side receives a received optical signal sent from the optical cable by a photodiode element, generates a received photocurrent, and inputs it to the second laser diode driver,
In the other optical transceiver of the station side and the terminal side, the second laser diode driver inputs an output current obtained by multiplying the received photocurrent by a ratio given in advance to the second laser diode element and transmits the signal. Send out an optical signal to the optical cable,
In the optical transceiver on one of the station side and the terminal side, the photodiode element receives the received optical signal sent from the optical cable,
An optical transmission level setting method, wherein an optical power detection means detects the intensity of the received optical signal received by one of the optical transceivers of the station side and the terminal side and displays it on a display unit.

(Supplementary Note 6) The process in which the second laser diode driver inputs the output current to the second laser diode element includes:
An A / D converter converts the received photocurrent into an input digital value,
The output determination unit determines whether the input digital value is within a range of numerical values given in advance,
The output determination unit determines an output digital value corresponding to the input digital value with reference to the contents of a lookup table stored in advance in a storage unit provided,
6. The optical transmission level setting method according to appendix 5, wherein an output current corresponding to the output digital value is input to the laser diode element by a D / A converter.

(Supplementary note 7) An optical transmission unit that converts a transmission data signal received from a station-side host device into a transmission optical signal and enters the optical cable; and a reception optical signal emitted from the optical cable is converted into a reception data signal. In an optical communication system provided on each of the station side and the terminal side, an optical transceiver comprising an optical receiver that outputs to the station side host device,
The received optical signal generated by receiving the received optical signal emitted from one of the station side and the terminal side and transmitted to the optical cable by the other optical transceiver of the station side and the terminal side is input. In the computer equipped with the laser diode driver
Converting the received photocurrent into an input digital value;
A procedure for determining whether the input digital value is within a range of numerical values given in advance;
Determining an output digital value corresponding to the input digital value with reference to the contents of a lookup table provided in advance;
And an optical transmission level setting program for causing a laser diode element to input an output current corresponding to the output digital value.

  It can be widely used in an optical communication system using an optical transceiver. In particular, it is suitable for an optical communication system in which a large number of optical transceivers are mounted on one optical communication device.

10, 101, 102, 103, 104, 105, 106, 210 Optical transceiver 10a Optical transmitter 10b Optical receiver 11, 211 LDD
11a Current mirror circuit 11b Optical signal generator 11c Switch 12 LD element 13 PD element 14 TIA
16 Optical power detection means 20, 131, 132, 133 Optical cable 100 Optical communication system 110 Communication station side communication device 121, 122, 123 Terminal side communication device 211a A / D conversion unit 211b Output determination unit 211c D / A conversion unit 211d LUT Storage unit 211e switch

Claims (7)

An optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable, and a reception optical signal sent from another network via the optical cable to a reception data signal And an optical transceiver that outputs to the station-side host device,
The optical transmission unit includes a laser diode element that emits the transmission optical signal, and a laser diode driver that converts the transmission data signal into an output current that drives the laser diode element to emit light and inputs the output current to the laser diode element. ,
A photodiode element that receives the received optical signal and generates a received photocurrent; and a transimpedance amplifier that amplifies and converts the received photocurrent and outputs the received data signal as the received data signal. As well as
The optical transceiver, wherein the laser diode driver inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element.   2. The optical transceiver according to claim 1, wherein the laser diode driver includes a switch for switching which of the transmission optical signal and the reception photocurrent is input to the laser diode element. 3.   2. The optical transceiver according to claim 1, wherein the laser diode driver includes a current mirror circuit that inputs an output current obtained by multiplying the received photocurrent by a predetermined ratio to the laser diode element. The laser diode driver is
An A / D converter that converts the received photocurrent into an input digital value;
An output determination unit that determines an output digital value corresponding to the input digital value with reference to the contents of a lookup table stored in advance in a storage unit provided;
The optical transceiver according to claim 1, further comprising: a D / A converter that inputs the output current corresponding to the output digital value to the laser diode element. An optical transmission unit that converts a transmission data signal sent from a station-side host device into a transmission optical signal and sends it to an optical cable, and a reception optical signal sent from another network via the optical cable to a reception data signal In the optical communication system provided on each of the station side and the terminal side, an optical transceiver provided with an optical receiving unit that outputs to the station side host device,
In one of the optical transceivers of the station side and the terminal side, the transmission data signal is converted and input to an output current that causes the first laser diode driver of the optical transmission unit to drive the first laser diode element to emit light. Sending a transmission optical signal to the optical cable,
The other optical transceiver of the station side and the terminal side receives a received optical signal sent from the optical cable by a photodiode element, generates a received photocurrent, and inputs it to the second laser diode driver,
In the other optical transceiver of the station side and the terminal side, the second laser diode driver inputs an output current obtained by multiplying the received photocurrent by a ratio given in advance to the second laser diode element and transmits the signal. Send out an optical signal to the optical cable,
In the optical transceiver on one of the station side and the terminal side, the photodiode element receives the received optical signal sent from the optical cable,
An optical transmission level setting method, wherein an optical power detection means detects the intensity of the received optical signal received by one of the optical transceivers of the station side and the terminal side and displays it on a display unit. A process in which the second laser diode driver inputs an output current to the second laser diode element;
An A / D converter converts the received photocurrent into an input digital value,
The output determination unit determines whether the input digital value is within a range of numerical values given in advance,
The output determination unit determines an output digital value corresponding to the input digital value with reference to the contents of a lookup table stored in advance in a storage unit provided,
6. The optical transmission level setting method according to claim 5, wherein an output current corresponding to the output digital value is input to the laser diode element by a D / A converter. A transmission data signal received from the station-side host device is converted into a transmission optical signal and incident on the optical cable, and a reception optical signal emitted from the optical cable is converted into a reception data signal and the station-side host is converted. In the optical communication system provided on each of the station side and the terminal side, an optical transceiver including an optical receiving unit that outputs to the device,
The received optical signal generated by receiving the received optical signal emitted from one of the station side and the terminal side and transmitted to the optical cable by the other optical transceiver of the station side and the terminal side is input. In the computer equipped with the laser diode driver
Converting the received photocurrent into an input digital value;
A procedure for determining whether the input digital value is within a range of numerical values given in advance;
Determining an output digital value corresponding to the input digital value with reference to the contents of a lookup table provided in advance;
And an optical transmission level setting program for causing a laser diode element to input an output current corresponding to the output digital value.

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