JPH01175423A - Optical data transmission system - Google Patents

Abstract

PURPOSE:To enable communication between slave stations, or a master station and each slave station by connecting the input terminal and output terminal of the main optical waveguide of each slave station optical directional coupler with optical fibers, and further connecting the output terminal of a subordinate optical waveguide to the input terminal of a data processing circuit and the input terminal of the subordinate optical waveguide to the output terminal of the data processing circuit. CONSTITUTION:A 4th terminal 24 among four terminals of the optical directional coupler 24 is connected to the input terminal of a photoelectric converter 14, whose electric output is inputted to a data processing circuit 15. Consequently, communication from a slave station 11 to a right-side slave station 11 becomes possible. Namely, a transmission line is formed from the 2nd terminal 22 of the optical directional coupler 20 of the slave station 11 to the data processing circuit 15 through the 1st terminal 21 of the optical directional coupler 20 of the other slave station 11. Further, this transmission system has the same functions as before, and data sent out of a certain slave station is received by all slave stations on the side of the master station about said slave station. Data sent out of all the slave stations are received by the master station 12 through through optical directional couplers 20 of the slave stations without fail.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission system using optical fibers.

[Prior Art] A conventional data transmission system is basically constructed by arranging a plurality of slave stations 11 in a straight line and arranging a master station 12 at one end thereof, as shown in FIG. has been done. Master station 1
2 collects data from the slave station 11, and depending on the case, the master station 12 transmits data, command signals, etc. to the slave station 11. The eleventh side of communication control in FIG.
converts the optical signal arriving from the optical fiber 10 into the photoelectric converter 14
The signal is then converted into an electrical signal, added with self-information by the data processing circuit 15, converted back into an optical signal by the electrical-optical converter 13, and sent to the optical fiber 10. The master station 12 converts the optical signal that has arrived through the optical fiber 10 into an electrical signal using the charging converter 14, and performs necessary processing such as processing, storage, and display in the central device 16.

The disadvantage of the system configured as shown in FIG. 4 is that a certain slave station 11
If any of the photoelectric converter 1/I, the electro-optical converter 13, or the 1 data processing circuit 15 fails, communication from the slave station 11 on the side farther from the slave station 11 will be impossible. ·be.

The solution to this problem is the configuration shown in FIG. Each slave station 1
The signal output from the data processing circuit 15 of 1 is sent to the electro-optical converter 1.
3 is converted into light, which passes through the optical directional coupler 20 and exits to the optical fiber 10.

Specific examples of optical directional coupling 20 include those shown in FIGS. 6 and 7. First, the star light directional coupler 30 shown in FIG. 6 is made by twisting together a plurality of optical noa inos and melting them by the flame of a burner. This fusion part 31
At d3, signal mixing is performed, and the light that enters the first terminal 21 exits to the third terminal 23 and fourth terminal 24. 1.
:The 20th terminal 22 (the light that enters also exits from the third terminal 23 and the fourth terminal 24I.

However, the light that enters the first terminal 21 does not exit to the second terminal 22, and the light that enters the third terminal 23 does not exit to the fourth terminal.

Next, the polishing type optical directional coupler 32 shown in FIG.
As shown in a), the cladding part 35 of the optical fiber is polished, embedded in the groove of the substrate 36 and fixed with adhesive 33,
Next, two substrates 36 are bonded together as shown in FIG. 7(b).

In this case, the first terminal 21, the second terminal 22, and the third terminal 23
, the light input to and output from the fourth terminal 24 operates in exactly the same way in the case of the star light directional coupler 30 with respect to the directionality of the coupling.

Next, communication control is shown in FIG. Figure 8 (a)
is 6 formulas in which each slave station 11 transmits data in order from the slave station 11 farthest from the parent 812 to a, b, c, etc. For example, the slave station to transmit data C is Self-information C is added after the information of the slave station before the station. (b) in Figure 8 is a method in which each slave station °1'1 transmits data a, b, c, etc. at a timing unrelated to the others, and a communication control section is almost not required. , Since data sometimes collides as shown in the figure, it is necessary for the master station 12 to perform appropriate processing, such as discarding the collided data. The master station 12 issues an inquiry signal al, 1)1, etc., and in response, each slave station 11 sends a2. This is a method of transmitting self-information such as b2... Since the master station 12 controls the transmission timing, there is no problem of collision like the one that occurred in ([1)].

``Problems to be Solved by the Invention'' When the system is configured as shown in Figure 5, even if the data processing circuit 15 or the electro-optical converter 13 of one slave station fails, information transmission from other slave stations will not be possible. In other words, the configuration shown in FIG. 5 can be said to be superior to that shown in FIG. 4 in terms of overall system reliability, but it also has a major drawback. Transmission is possible only to station 12, and between slave stations ICl3 or from parent 812 to slave station 1
Transmission of 11\ is impossible. Therefore, it is extremely inconvenient that the communication control method -( can only be used in (b) of Figure 8. In the case of the configuration shown in Fig. 4, =6- communication control method (-if, (b)) can be used. is possible.

An object of the present invention is to enable communication between a master station and each slave station while maintaining high reliability against failures of slave stations in an optical data transmission system using an optical directional coupler. Our objective is to provide optical data transmission systems.

Another object of the present invention is to enable communication (+E) between slave stations, such as between slave stations and a master station, in an optical data transmission system using an optical directional coupler, thereby achieving high reliability and An object of the present invention is to provide an optical data transmission system that enables collision-free data transmission.

[Means for solving the problem] The first invention of the present application has a master station at one end of a single optical fiber, and a plurality of slave stations in the middle of the optical fiber. J. Connect the two non-adjacent terminals of the /I terminal of the optical directional coupler to the above optical fiber, and connect one of the remaining two terminals to the input terminal of the data processing circuit via the photoelectric converter. , the other terminal is connected to the output terminal of the data processing circuit via an electro-optical converter, and in the master station, one end of the optical fiber is connected to the input terminal of the central device via a photo-electric converter. The optical data transmission system is constructed using the following methods.

In the second invention of the present application, the configuration of the slave station is the same as the first invention, but in the master station, one end of the optical fiber is connected to the central device through an optical directional coupler and a photoelectric converter. Of the remaining two terminals of this optical directional coupler, the remaining terminal on the same side as the optical fiber is not used, and the remaining terminal on the photoelectric converter side is connected to the central device via the electro-optical converter. A terminal station is installed at the end of the optical fiber that is not connected to the master station, and sends back the optical data transmitted through the optical fiber to the optical fiber. It constitutes the transmission system.

[Function] The present invention is directed to the coupling direction of the optical directional coupler, that is, the incoming horn light at the input terminal (first terminal) of the main optical waveguide is directed to the output terminal (third terminal) of the main optical waveguide and It is transmitted to the output terminal (fourth terminal) of the auxiliary optical waveguide, but not to the input terminal (second terminal) of the auxiliary optical waveguide, and is transmitted to the output terminal (4th terminal) of the main optical waveguide.
The input light to the input terminal (3rd terminal) of the main optical waveguide is
terminal) and m] input terminal of the optical waveguide (second terminal))
This utilizes the characteristic that the signal is transmitted to the output terminal (the 11th terminal) of the sub-optical waveguide.

In the first invention, the optical directional coupler of each slave station connects the input terminal and output terminal of its main optical waveguide to an optical fiber, and connects the output terminal of the sub optical waveguide to the optical fiber for data transmission via a photoelectric converter. The input terminal of the auxiliary optical waveguide is connected to the input terminal of the processing circuit via an electro-optical converter to the output terminal of the data processing circuit.

Therefore, the data emitted by all the slave stations can be received by the -C1 master station from the input terminal of the sub-waveguide of the optical directional coupler of the slave station through the output terminal of the main waveguide and the optical fiber, and at the same time The data transmitted by the station is transferred from the input terminal of the main waveguide of the optical directional coupler to the output terminal of the sub optical waveguide at all of the slave stations on the master station side.
1 can be received. Often, even if one slave station fails, the rest of the system remains fully operational.

In the second invention, the master station is also connected to one end of the optical fiber via the optical directional coupler, the input terminal of the sub optical waveguide of this optical directional coupler is not used, and the output terminal is connected to the electro-optical converter. The cable 1 connects to the output terminal of the central device, and the other end of the optical fiber is transmitted through an optical fiber.
Boo C is here. Therefore, as in the case of the first invention, the data transmitted by all the slave stations can be received by the master station, and the data transmitted by one slave station can be received by all the slave stations closer to the master station than the slave station. Of course, the data transmitted by the master station is received by all the slave stations, and the data transmitted by a slave station is transmitted via the optical fiber, the master station, the optical fiber, the terminal station, and the optical fiber. Then, it can be received by a slave station located closer to the terminal station than the slave station, i<-r.

Therefore, all the slave stations and the master station or all the slave stations are connected directly or via the master station or the terminal station, and two-way communication becomes possible. Therefore, there are no restrictions on the type of communication control method. Even if a certain slave station fails -C-10=, all other parts of the system operate normally, which is the same as in the case of the first invention.

The terminal station can be configured as a sub-base station having exactly the same configuration as the base station, or it can be configured as a total reflection end of an optical fiber.

In addition, in the present invention, the optical directional coupler is concerned only with the directionality of the coupling terminal with respect to the traveling direction of the light. It does not matter whether it is a constant or not. Therefore, any of the optical directional couplers illustrated in FIGS. 6 and 7 can be used.

[Example] The present invention will be explained below based on illustrated embodiments.

In FIG. 1, a master station 12 is installed at one end of one optical fiber 10, and a plurality of slave stations 11 are installed in the middle of the optical fiber 10.
1. - indicates a fiber optic transmission system; Each slave station 1
1, the four terminals 2' of the optical directional coupler 20
l The first terminal 21 that is not adjacent to each other among 22, 23, and 24
．． The third terminal 23 is connected to the optical fiber 10, and the output terminal of the electro-optical converter 13 connected to the output terminal of the data processing circuit 15 is connected to the second terminal 22 of the two remaining terminals 22 and 24. are doing. Furthermore, at J5 in the master station 12, one end of the optical fiber 10 is connected to the input terminal of a photoelectric converter 14, and the output terminal of the photoelectric converter 14 is connected to the input terminal of the central device 16. The configuration up to this point is the same as the system shown in FIG.

However, in the optical data transmission system shown in FIG. 1, among the four terminals of the optical directional coupler 20, the fourth terminal 24, which is not used in FIG. The electric horn of the photoelectric transformer 14 is input to the data processing circuit 15.

By improving the first step, communication from the slave station 11 to the slave station 11 on the right side, which was not possible with the configuration shown in FIG. 5, becomes possible. That is, the second terminal 22 of the optical directional coupler 20 of the slave station 11
→ third terminal 23 → optical fiber 10 → first terminal 21 of optical directional coupler 20 of other slave station 1'1 → fourth terminal 24-> photoelectric converter 14 → data processing circuit 15 transmission line It is formed. Further, in the configuration of FIG. 1, -C has exactly the same function as that of FIG. 5. Therefore, data transmitted by a certain slave station can be received by all the slave stations closer to the master station than the slave station. Of course, the data issued by all the slave stations can also be received by the master station 12 via the first terminal 21, third terminal 23 and optical fiber 10 of the optical directional coupler 20 of the slave station.

Next, FIG. 2 shows a slightly more complicated system configuration than that shown in FIG. 1, with enhanced communication functions. The following two points differ from Fig. 1.

The first is that the master station 17 also uses an optical directional coupler 20 for connection to the optical fiber 10, and the fourth terminal 24 of the optical directional coupler 20 is connected to an electrical-optical converter connected to the central device 16. The optical output terminal of the converter 13 is connected, and the information output from the central device 16 is connected to the optical fiber 'IO, and the third terminal 23 is connected to the input terminal of the photoelectric converter 14, and the information is transmitted from the optical fiber 10 to the master station 17. The arriving signal is sent to the first optical directional coupler 20.
The signal is taken into the -C master station 17 via the terminal 21 → third terminal 23.

Second, at the end of the optical fiber 1o opposite to the master station 17,
A sub-master station 18, which is exactly the same as the main station 17, is installed as a terminal station that sends the optical data transmitted through the optical fiber 10 back to the optical fiber 1o. , the optical signal that has passed through the optical fiber 10 and the optical directional coupler 2o from the master station 17 is photoelectrically transmitted from the third terminal 23 of its own optical directional coupler 20 via the input terminal 21. The data is captured into the converter 14 and its electrical output is input into the central device 16. In principle, the central device 16 of the submaster station 18 converts the captured data as it is into an optical signal using the electro-optical converter 13, and sends the data to the optical directional coupler 20. The second terminal 22 of
-> Return to the optical fiber 10 via the third terminal 23.

The first and second ideas described above enable free communication. That is, first, all the slave stations 11 can transmit to the master station 17 and can also transmit to the slave stations 11 on the right side of themselves.Furthermore, the master station 17 can transmit the following information: -C sub-master station 1 via optical directional coupler 20
8, and the sub-master station 18 returns the signal in the direction of the master station 17, as described above. The folded signal is transmitted from the first terminal 21 of the optical directional coupler 20 of each slave station 11 to the fourth terminal.
It passes through the terminal 24 and reaches the photoelectric converter 14 of each slave station 11. That is, the signal transmitted from the master station 17 reaches each -C slave station 11 via the sub-master station 18. Therefore, all slave stations 11 and master station 17 are capable of bidirectional communication.

Furthermore, in the configuration shown in FIG. 1, each slave station 11 could only transmit to slave stations located closer to the master station than itself;
In the case of the configuration shown in the figure, slave station 11-) master station 17→sub-master station'
18→Slave station"1 Since there is a communication route 1~ of 1, communication between arbitrary slave stations is possible.Moreover, in the case of this configuration,
Any of (a), (b), and (c) in FIG. 8 can be used as the communication control method.

FIG. 3 shows a modified embodiment of FIG. What is different from FIG. 2 is that the optical data transmitted through the optical fiber 104 is sent back to the optical fiber 10 and the terminal station
The point is that the AE'I 8 is not used, and instead an optical fiber total reflection end 19 is provided to completely reflect the signal coming from the optical fiber 10 so that it is folded back. Total reflection end 19 (
This can be achieved by polishing the end face of the optical fiber and applying 40 layers of metal film. The operational functions of the system shown in FIG. 3 are exactly the same as those shown in FIG. 2, so a description thereof will be omitted.

In this way, the front reflection end 19 of the optical fiber is installed between the terminal stations (
By doing so, the sub-master station 18 is eliminated and the system is simplified.

[Effects of the Invention] As described above, the optical data transmission system of the present invention enables communication from a slave station to a slave station I\ located closer to the master station, which was previously impossible. Furthermore, even if a certain slave station fails, other parts of the system operate normally, so reliability is high.

In addition, by configuring the master station at one end of the optical fiber to be able to transmit data, and by setting up a terminal station for data return lJ at the other end of the optical fiber, all slave stations and the master station (j bidirectional communication In addition, it is possible to communicate between any slave stations (4T).Furthermore, since various communication control methods can be applied, it is possible to construct a highly flexible system.

[Brief explanation of the drawing]

FIG. 1 shows an example of the configuration of an optical data transmission system according to the present invention, FIG. 2 shows an example of the configuration of another optical data transmission system according to the present invention, and FIG. Figures 4 and 5 show the configuration of the conventional system, respectively, and (a) and (b) of Figures 6 and 7 show the optical direction, respectively. Diagrams for explaining the structure and operation of the sexual coupler, (a), (b), and (c) in Figure 8
are diagrams each showing a communication control method. In the figure, 10 is an optical fiber, 11 is a slave station, 12 and 17 are a master station, 13 is an electro-optical converter, 17'l is a photo-electric converter, 15
is a data processing circuit, 1G is a central unit, 18 is a sub-master station, 1
9 indicates a terminal station, and 20 indicates a directional coupler. Patent Applicant Hitachi Cable Co., Ltd. Representative Patent Attorney Nobuyuki Kinutani 171 Procedures Official Filing (Method) April 6, 1985 Commissioner of the Patent Office Kunio Ogawa 1, Indication of Case Patent Application 1988- 334.872 No. 2,
Name of the invention: Optical data transmission system 3, relationship with the amended case Patent Applicant: (512) Hitachi Cable Co., Ltd. 4, Agent postal code: 105 Atagoyama 1-6-7, Minato-ku, Tokyo Atagoyama attorney Building 5, date of amendment order: March 29, 1985 (shipping port) 6 Drawings subject to amendment (all drawings)

Claims (4)

[Claims] (1) A master station is provided at one end of a single optical fiber, and a plurality of slave stations are provided in the middle of the optical fiber. The terminals are connected to the optical fiber, one of the remaining two terminals is connected to the input terminal of the data processing circuit via a photoelectric converter, and the other terminal is connected to the output terminal of the data processing circuit via the electro-optical converter. 1. An optical data transmission system characterized in that, at a master station, one end of the optical fiber is connected to an input terminal of a central device via a photoelectric converter. (2) A master station is provided at one end of a single optical fiber, and a plurality of slave stations are installed in the middle of the optical fiber. The terminals are connected to the optical fiber, one of the remaining two terminals is connected to the input terminal of the data processing circuit via a photoelectric converter, and the other terminal is connected to the output terminal of the data processing circuit via the electro-optical converter. At the master station, one end of the optical fiber is connected to the input terminal of the central device via an optical directional coupler and a photoelectric converter, and the remaining two ends of the optical directional coupler are connected to
The remaining terminals on the same side as the optical fiber are not used, and the remaining terminals on the photoelectric converter side are connected to the output terminal of the central device via the electro-optic converter, and the terminals on the same side as the optical fiber are connected to the output terminal of the central device. An optical data transmission system characterized in that a terminal station is provided at the end of the optical fiber, which sends optical data transmitted through the optical fiber back to the optical fiber. (3) The optical data transmission system according to claim 2, wherein the terminal station is a sub-master station having exactly the same configuration as the master station. (4) The optical data transmission system according to claim 2, wherein the terminal station is a total internal reflection end of an optical fiber.