JP2003338788A - Optical fiber transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber transmission system which works with a little jitter or has no need of a transfer line for switching signals in a wavelength-multiplexed two-way transmission with one-core optical fibers between master and slave units. <P>SOLUTION: The optical fiber transmission system comprises an optical combining-branching circuit at a master unit for combining-branching a light signal at 1:2; an optical switch at a slave unit for selecting one line from two lines; and a switching control circuit for switching the optical switch according to received information from an optical receiver circuit at the slave unit. The optical combining-branching circuit is connected with the optical switch through two optical fiber transmission lines. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber transmission system in which optical fiber transmission lines are duplicated.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional optical fiber transmission system in which an optical fiber transmission line is duplicated. In FIG. 1, an optical transmitter circuit 13-1 and an optical receiver circuit 14-are provided on the main device side.
1, a wavelength multiplex demultiplexer 11 and an optical coupling / branching circuit 51 are provided,
An optical receiving circuit 15-1 and an optical transmitting circuit 16-are provided on the slave side.
1, a wavelength multiplex demultiplexer 12, and an optical coupling / dividing circuit 52.

With this structure, the system operates as follows. Optical transmitter circuit 13 on the side of the main device
The optical signal from 1 is multiplexed into one optical fiber by the wavelength division multiplexing / demultiplexing device 11, and the optical signal from the optical multiplexing / branching circuit 51
It is branched into the optical fiber transmission lines 41 and 42 of the book. The two optical signals propagating through the two optical fiber transmission lines are combined by the optical combining / branching circuit 52 on the side of the slave device. The combined optical signals are demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is multiplexed into one optical fiber by the wavelength division multiplexing / demultiplexing device 12, and the two optical fiber transmission lines 41 are combined by the optical add / drop circuit 52. It branches to 42.
The two optical signals that have propagated through the two optical fiber transmission lines are combined by the optical combining / branching circuit 51 on the main device side. The combined optical signals are demultiplexed by the wavelength division multiplexing demultiplexer 11 and received by the optical receiving circuit 14-1.

Here, since the optical signal is evenly branched and propagated in the two optical fiber transmission lines, even if one optical fiber transmission line is disconnected due to a failure, the other optical fiber transmission lines are The propagating optical signal can be received, and communication is not interrupted. However, an optical loss of 3 dB is essentially generated when passing through the optical add / drop circuit. Actually, the optical loss is 4 to 5 dB. That is, an optical loss of 4 to 5 dB occurs due to the optical add / drop circuit. Therefore, if the receiving sensitivity of the optical receiving circuit is fixed, it is necessary to increase the optical output of the optical transmitting circuit by 4 to 5 dB.
If the output of the optical transmission circuit is made constant, it is necessary to improve the reception sensitivity of the optical reception circuit, which has been a factor of enormous cost increase. Furthermore, since two optical fiber transmission lines are used at the same time, if there is a distance difference between the two optical fiber transmission lines, it has been a cause of jitter in the optical receiving circuit. Also, 2
If the optical fiber transmission lines of the book are laid on different routes, there will be a distance difference, so this system cannot be applied.

FIG. 2 shows another optical fiber transmission system in which the optical fiber transmission line is duplicated. In FIG. 2, an optical transmitter circuit 13-1, an optical receiver circuit 14-1, a wavelength multiplex demultiplexer 11, an optical switch 53, and a switching control circuit 55 are provided on the main device side, and an optical device is provided on the slave device side. Receiver circuit 15-1, optical transmitter circuit 16-1, wavelength multiplex demultiplexer 12, optical switch 5
4. A switching control circuit 56 is provided.

With this structure, the system operates as follows. Optical transmitter circuit 13 on the side of the main device
The optical signal from 1 is multiplexed into one optical fiber by the wavelength multiplex demultiplexer 11, and guided to either of the two optical fiber transmission lines 41 or 42 by the optical switch 53. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 12 by the optical switch 54 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is multiplexed into one optical fiber by the wavelength division multiplexing / demultiplexing device 12, and the two optical fiber transmission lines 41 and the optical fiber are transmitted by the optical switch 54. Fiber transmission line 4
You are led to one of the two. The optical signal propagating through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 by the optical switch 53 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuit 14-1.

Here, since the two optical fiber transmission lines are switched by the optical switch, even if one optical fiber transmission line is disconnected due to a failure, an optical signal propagating in another optical fiber transmission line. Can be received and communication will not be interrupted. That is, when the optical fiber transmission line on the operating side of the two optical fiber transmission lines is cut, the optical receiving circuit 15-1 on the slave device side detects the disconnection of the optical signal. The optical receiving circuit 14-1 on the side of the main device also detects the interruption of the optical signal. At the same time, the switching control circuit 55 and the switching control circuit 56
Instructs the synchronous switching of the optical fiber transmission lines in the optical switch 53 and the optical switch 54 through the transfer line (not shown) of the switching signal. However, when the optical switches are installed at both ends, in the conventional optical fiber transmission system, it is necessary to synchronize which optical fiber transmission path is switched with each other, and a switching signal transfer line for that purpose must be provided.

[0008]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides an optical fiber transmission system with less jitter or an optical fiber transmission system that does not require a switching signal transfer line. And

[0009]

In order to achieve the above-mentioned object, the present invention is solved by the following constitution. The first invention of the present application is an optical fiber transmission system for performing wavelength division multiplex bidirectional transmission between a master device and a slave device by means of a one-core optical fiber. An optical switch for selecting one route from two routes is provided on the side of the slave device, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission lines. The optical fiber transmission system is characterized by comprising a switching control circuit for switching the optical switch according to information received from the optical receiving circuit of the slave device.

A second aspect of the present invention is an optical fiber transmission system for performing wavelength division multiplexing bidirectional transmission between a master device and a slave device by means of a one-core optical fiber. And an optical switch for selecting one route from two routes on the side of the slave device, and two optical fiber transmission lines between the optical coupling / branching circuit and the optical switch. And a switching control circuit that switches the optical switch according to detection information from an optical signal detection circuit installed between the optical switch and the slave device.

A third aspect of the present invention is an optical fiber transmission system for performing wavelength division multiplexing bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein the main device has an optical signal of 1: 2. An optical switch for selecting one route from two routes on the side of the slave device, and two optical fiber transmission lines between the optical coupling / branching circuit and the optical switch. And an optical fiber transmission comprising a switching control circuit for switching the optical switches according to detection information from optical signal detection circuits respectively connected between the two optical fiber transmission lines and the optical switch. System.

A fourth invention of the present application is an optical fiber transmission system for performing wavelength division multiplex bidirectional transmission between a master device and a slave device by means of a single-core optical fiber, on each of the master device side and the slave device side. Is provided with an optical switch for selecting one route from two routes, the two optical switches are connected by two optical fiber transmission lines, and the main device is provided with information received from an optical receiving circuit of the main device. And a switching control circuit for switching the optical switch on the side of the slave device according to the information received from the optical receiving circuit of the slave device. Is.

A fifth aspect of the present invention is an optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein each of the main device side and the slave device side Is provided with an optical switch for selecting one route from two routes, and the two optical switches are connected by two optical fiber transmission lines, and between the optical switch on the side of the main device and the main device. A switching control circuit for switching the optical switch on the side of the main device according to detection information from the optical signal detection circuit installed on the optical device, and an optical signal detection installed between the optical switch on the side of the slave device and the slave device. An optical fiber transmission system, comprising: a switching control circuit that switches an optical switch on the side of the slave device according to detection information from the circuit.

A sixth aspect of the present invention is an optical fiber transmission system for performing wavelength-division multiplex bidirectional transmission between a master device and a slave device by means of a one-core optical fiber, on each of the master device side and the slave device side. Is provided with an optical switch for selecting one route from two routes, the two optical switches are connected by two optical fiber transmission lines, and the two optical fiber transmission lines are connected to the main device side. A switching control circuit for switching the optical switch on the side of the main device according to detection information from an optical signal detection circuit inserted between the optical switches, the two optical fiber transmission lines and the optical switch on the side of the slave device. And a switching control circuit for switching the optical switch on the slave device side according to the detection information from the optical signal detection circuit inserted between the optical fiber transmission system and the optical fiber transmission system.

A seventh invention of the present application is an optical fiber transmission system for performing wavelength-division-multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of a single-core optical fiber. An optical multiplexer / demultiplexer circuit for splitting an optical signal in a one-to-two manner is provided, and an optical switch for selecting one route from two routes is provided on the side of the plurality of slave devices. Are connected by two optical fiber transmission lines,
An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to information received from each optical receiving circuit of the plurality of slave devices.

An eighth invention of the present application is an optical fiber transmission system for performing wavelength-division multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of a single-core optical fiber. An optical branching circuit for branching an optical signal in a one-to-two relationship is provided, and an optical switch for selecting one path from two paths is provided on the side of the plurality of slave devices, and the optical switch is provided between the optical branching circuit and the optical switch. Are connected by two optical fiber transmission lines,
An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to detection information from an optical signal detection circuit installed between the optical switch and the plurality of slave devices.

The ninth invention of the present application is an optical fiber transmission system for performing wavelength-division-multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of a single-core optical fiber. An optical multiplexer / demultiplexer circuit for splitting an optical signal in a one-to-two manner is provided, and an optical switch for selecting one route from two routes is provided on the side of the plurality of slave devices. Are connected by two optical fiber transmission lines,
An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to detection information from an optical signal detection circuit inserted between the two optical fiber transmission lines and the optical switch.

A tenth aspect of the present invention is an optical fiber transmission system for performing wavelength-division-multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of an optical fiber having one core. An optical switch for selecting one route from two routes is provided on each of the plurality of slave devices, and the two optical switches are connected by two optical fiber transmission lines. A switching control circuit that switches optical switches on the side of the plurality of main devices according to the received information from the optical receiving circuit, and an optical switch on the side of the slave devices according to received information from the optical receiving circuits of the plurality of slave devices. An optical fiber transmission system, characterized in that it comprises a switching control circuit, respectively.

The eleventh invention of the present application is an optical fiber transmission system for performing wavelength-division multiplex bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of a single-core optical fiber. An optical switch for selecting one route from two routes is provided on each of the plurality of slave devices, and the two optical switches are connected by two optical fiber transmission lines. Side optical switches and a switching control circuit for switching optical switches on the side of the plurality of main devices according to detection information from an optical signal detection circuit installed between the plurality of main devices, and a side of the plurality of slave devices. The optical switch and a switching control circuit for switching the optical switch on the side of the plurality of slaves according to detection information from an optical signal detection circuit installed between the plurality of slaves. Fiber transmission system It is a non.

The twelfth invention of the present application is an optical fiber transmission system for performing wavelength-division multiplex bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of an optical fiber of one core. An optical switch for selecting one route from two routes is provided on each of the plurality of slave devices, and the two optical switches are connected to each other by two optical fiber transmission lines. A switching control circuit for switching the optical switches on the side of the plurality of main devices according to detection information from optical signal detection circuits inserted between the transmission line and the optical switches on the side of the plurality of main devices; And a switching control circuit for switching the optical switches on the side of the plurality of slaves according to detection information from optical signal detection circuits inserted between the optical fiber transmission line and the optical switches on the side of the plurality of slaves, respectively. thing An optical fiber transmission system comprising.

The thirteenth invention of the present application is the main device side and the slave device side in the fourth to sixth inventions of the present application, or the plurality of main device sides in the tenth to twelfth inventions of the present application. And the plurality of slave devices have different totals of the time until the optical switch is switched after the optical switch is switched and the time until the optical switch is switched after the determination. The optical fiber transmission system according to the fourth to sixth or tenth to twelfth invention of the present application.

The fourteenth invention of the present application is the main device side and the slave device side in the fourth to sixth inventions of the present application, and the plurality of main device sides and the plurality of main device sides in the tenth and twelfth inventions of the present application. On the side of the plurality of slave devices, the time from the detection of the interruption of the optical signal to the determination of the interruption of the optical signal is longer than the time from the switching of the optical switch to the determination of the continuity of the optical signal. The optical fiber transmission system according to the fourth to sixth inventions or the twelfth to twelfth inventions of the present application characterized by being long.

A fifteenth invention of the present application is the plurality of slave devices according to the seventh to fourteenth inventions of the present application, further comprising transmission display circuits for displaying the states of the optical transmission circuits of the plurality of main devices, respectively. The optical fiber transmission system according to the seventh to fourteenth inventions of the present application.

The sixteenth invention of the present application is the slave device according to the third invention of the present application, or the plurality of slave devices according to the ninth invention of the present application, displaying the conduction state of the optical fiber transmission line in a non-operating state. An optical fiber transmission system according to the third or ninth invention of the present application, characterized by comprising a continuity display circuit.

The seventeenth invention of the present application is the slave device according to the first to sixth inventions of the present application, or the plurality of slave devices according to the seventh to twelfth applications of the present invention, in which one of the two optical fiber transmission lines is operated. The optical fiber transmission system according to any one of the first through sixteenth inventions of the present application, characterized by comprising an operation display circuit for displaying whether or not it is in a state.

In the means for solving the above problems, an optical fiber coupler or a waveguide type PL is provided in the optical coupling / branching circuit.
C (Planar Lightwave Circuit) can be applied. An optical fiber type, a micromirror or a waveguide type PLC can be applied to the optical switch. An optical fiber type or waveguide type optical directional coupler, an optical branching circuit or the like can be applied to the optical signal coupling portion of the optical signal detection circuit. The optical branching ratio of the passing side and the detecting side in the optical signal detecting section of the optical signal detecting circuit is 1:
It does not have to be 1. The optical branching ratio is sufficient so that the optical signal detection circuit can secure an optical level enough to detect disconnection and continuity of the optical signal. In the above description, switching is performed for two optical fiber transmission lines, but the present invention can be extended to the case of three or more optical fiber transmission lines.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. (Embodiment 1) A system configuration of this embodiment is shown in FIG. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end and an optical switch is provided at the other end, and the optical switch is switched according to the information received from the receiving circuit.

In FIG. 3, an optical transmitter circuit 13-1, an optical receiver circuit 14-1, and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1. The optical multiplexer / branching circuit 23 is provided, and the optical receiver circuit 15-1, the optical transmitter circuit 16-1, and the wavelength multiplexing / multiplexing demultiplexer 1 are provided on the slave device side.
2, an optical switch 22, a switching control circuit 36, and an operation display circuit 37.

With such a configuration, the system of the present embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Optical multiplexer / demultiplexer circuit 2
It is branched into two optical fiber transmission lines 41 and 42 by 3. The two optical signals that have propagated through the two optical fiber transmission lines are transmitted to the wavelength multiplex demultiplexer 1 by the optical switch 22 on the slave side.
Guided to 2. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is multiplexed into one optical fiber by the wavelength multiplex demultiplexer 12, and the two optical fiber transmission lines 41 and the optical signal are transmitted by the optical switch 22. It is guided to one of the fiber transmission lines 42. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 via the optical coupling / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuit 14-1.

As described above, since the communication is performed only by one optical fiber transmission line by switching the optical switch provided at one end, even if there is a distance difference between both optical fiber transmission lines, the jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 3, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in operation. This optical fiber transmission line 4
When 1 is disconnected due to a failure, the optical receiving circuit 15-1 detects the disconnection of the optical signal. Based on the received information from the optical receiving circuit 15-1 that the optical signal is disconnected, the switching control circuit 3
Reference numeral 6 indicates switching of the optical switch 22. Optical switch 2
2 selects another optical fiber transmission line 42. The optical receiving circuit 15-1 receives the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 according to the received information from the optical receiving circuit 15-1 that the optical signal is conducted. Since the function of detecting an optical signal can be easily added to the optical receiving circuit on the side of the slave device, the received information can be extracted by using this function. Since the optical signal from the optical transmission circuit 16-1 propagates through the optical fiber transmission path selected by the optical switch 22, the optical reception circuit 14-1 also detects the optical signal. When the switching control circuit 36 performs switching control with a protection time for interruption or conduction of an optical signal, stable operation is ensured even when the optical fiber transmission path is instantaneously interrupted or when the optical fiber transmission path is switched. be able to.

In this embodiment, the switching control circuit 36 controls switching of the optical fiber transmission line. When a failure occurs in the optical fiber transmission line and the operating optical fiber transmission line is switched, it may be desired to know which of the two optical fiber transmission lines is in operation. In FIG. 3, the switching control circuit 36 controls which optical fiber transmission line is in the operating state. Therefore, based on the information from the switching control circuit 36, the operation display circuit 37 displays which of the optical fiber transmission lines is in the operating state. The display method includes both the lamp display of the device and the display on the computer. By knowing the operational status of the optical fiber transmission line,
It is possible to restore and maintain the non-operational optical fiber transmission line without stopping the communication service. Similarly, in the following embodiments, by displaying the operation status of the optical fiber transmission line on the operation display circuit, it is possible to restore or maintain the optical fiber transmission line in the non-operational state.

(Second Embodiment) FIG. 4 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end and an optical switch is provided at the other end, and the optical information is received by the optical signal detection circuit that monitors the optical fiber transmission line. Switch the switch.

In FIG. 4, an optical transmitter circuit 13-1, an optical receiver circuit 14-1, and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1. The optical multiplexer / branching circuit 23 is provided, and the optical receiver circuit 15-1, the optical transmitter circuit 16-1, and the wavelength multiplexing / multiplexing demultiplexer 1 are provided on the slave device side.
2, an optical switch 22, an optical signal detection circuit 34, a switching control circuit 36, and an operation display circuit 37. Optical signal detection circuit 3
Reference numeral 4 detects an optical signal from the main device side that passes through the optical fiber transmission line 41 or 42. The optical signal detection circuit 34 is
If the optical signal from the slave device can be detected, the optical transmission circuit 16-1 can be monitored.

In such a configuration, the system of this embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Optical multiplexer / demultiplexer circuit 2
It is branched into two optical fiber transmission lines 41 and 42 by 3. The two optical signals that have propagated through the two optical fiber transmission lines are transmitted to the wavelength multiplex demultiplexer 1 by the optical switch 22 on the slave side.
Guided to 2. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is multiplexed into one optical fiber by the wavelength multiplex demultiplexer 12, and the two optical fiber transmission lines 41 and the optical signal are transmitted by the optical switch 22. It is guided to one of the fiber transmission lines 42. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 via the optical coupling / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuit 14-1. The optical signal detection circuit 34 is inserted between the optical switch 22 and the optical multiplexer / demultiplexer 12, and the optical signal detection circuit 34 is provided on the side of the main device.
To detect the optical signal from.

As described above, since the communication is performed only by one optical fiber transmission line by switching the optical switch provided at one end, even if there is a distance difference between both optical fiber transmission lines, the jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 4, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in the operating state. This optical fiber transmission line 4
When 1 is disconnected due to a failure, the optical signal detection circuit 34 detects the disconnection of the optical signal. Based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected, the switching control circuit 3
Reference numeral 6 indicates switching of the optical switch 22. Optical switch 2
2 selects another optical fiber transmission line 42. The optical signal detection circuit 34 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 34 that the optical signal is conducted. Since the optical signal detection circuit 34 monitors a part of the optical signal from the optical transmission circuit 13-1, the optical signal from the optical transmission circuit 13-1 is not greatly attenuated. Optical transmitter circuit 16-1
Since the optical signal from the signal propagates through the optical fiber transmission line selected by the optical switch 22, the optical receiving circuit 14-1 also detects the optical signal. When the switching control circuit 36 performs switching control with a protection time against disconnection or continuity of the optical signal, stable operation is secured against both instantaneous interruption of the optical fiber transmission line and switching of the optical fiber transmission line. can do. In this embodiment, since the received information from the optical receiving circuit is not used, the optical fiber transmission is performed even before the optical receiving circuit of the slave device becomes an obstacle or before the optical receiving circuit of the slave device is installed. Road switching control can be performed.

(Third Embodiment) FIG. 5 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end, and an optical switch is provided at the other end. To switch the optical switch.

In FIG. 5, an optical transmitter circuit 13-1, an optical receiver circuit 14-1, and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1. The optical multiplexer / branching circuit 23 is provided, and the optical receiver circuit 15-1, the optical transmitter circuit 16-1, and the wavelength multiplexing / multiplexing demultiplexer 1 are provided on the slave device side.
2, an optical switch 22, optical signal detection circuits 34 and 35, a switching control circuit 36, an operation display circuit 37, and a continuity display circuit 38. The optical signal detection circuits 34 and 35 detect optical signals from the main unit side via the optical fiber transmission lines 41 and 42, respectively. If the optical signal detection circuits 34 and 35 can detect the optical signals from the slave device side, respectively, the optical transmission circuit 16-1 and the optical switch 22 can be monitored.

With such a configuration, the system of the present embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Optical multiplexer / demultiplexer circuit 2
It is branched into two optical fiber transmission lines 41 and 42 by 3. The two optical signals that have propagated through the two optical fiber transmission lines are transmitted to the wavelength multiplex demultiplexer 1 by the optical switch 22 on the slave side.
Guided to 2. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is multiplexed into one optical fiber by the wavelength multiplex demultiplexer 12, and the two optical fiber transmission lines 41 and the optical signal are transmitted by the optical switch 22. It is guided to one of the fiber transmission lines 42. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 via the optical coupling / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuit 14-1. The optical signal detection circuit 34 is inserted between the optical fiber transmission path 41 and the optical switch 22, and the optical signal detection path 35 is inserted between the optical fiber transmission path 42 and the optical switch 22, respectively, and the optical transmission circuit 13 on the main device side is inserted. The optical signal from -1 is detected.

As described above, since the communication is performed only by one optical fiber transmission line by switching the optical switch provided at one end, even if there is a distance difference between both optical fiber transmission lines, jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 5, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in the operating state. This optical fiber transmission line 4
When 1 is disconnected due to a failure, the optical signal detection circuit 34 detects the disconnection of the optical signal. Based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected, the switching control circuit 3
Reference numeral 6 indicates switching of the optical switch 22. Optical switch 2
2 is switched to another optical fiber transmission line 42. After the switching of the optical switch 22, the optical signal detection circuit 35 has already detected the conduction of the optical signal. The optical switch 22 may instruct to switch to the optical fiber transmission path 42 after waiting for the detection information from the optical signal detection circuit 35 that the optical signal is conducting. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 35 that the optical signal is conducting. The optical signal detection circuit may stop its operation when the optical fiber transmission line is in a non-operational state. In this case, power consumption can be reduced. The optical signal detection circuit may keep operating even when the optical fiber transmission line is in a non-operational state. In this case, the conduction state of the optical signal can be constantly monitored.

The optical signal detection circuits 34 and 35 are the optical transmission circuit 1
Since a part of the optical signal from 3-1 is monitored, the optical signal from the optical transmission circuit 13-1 is not greatly attenuated. The optical signal from the optical transmission circuit 16-1 is the optical switch 2
Since it propagates through the optical fiber transmission line selected by 2, the optical receiving circuit 14-1 also detects the optical signal. When the switching control circuit 36 performs switching control with a protection time against disconnection or continuity of the optical signal, stable operation is secured against both instantaneous interruption of the optical fiber transmission line and switching of the optical fiber transmission line. can do. In this embodiment, since the received information from the optical receiving circuit is not used, the optical fiber transmission is performed even before the optical receiving circuit of the slave device becomes an obstacle or before the optical receiving circuit of the slave device is installed. Road switching control can be performed.

Furthermore, in the present embodiment, since two optical fiber transmission lines can be monitored at the same time, it is possible to monitor the conduction state of the optical fiber transmission line in the non-operational state. If one of the two optical fiber transmission lines is in the operating state and it is possible to know whether or not the other optical fiber transmission line is conducting, maintainability is improved. If there is a non-conduction state, the optical fiber transmission line must be restored. In the conductive state, even if a failure occurs in one, communication can be restored by switching to the other. In the present embodiment, an optical add / drop circuit is used on the side of the main device to branch the optical signal from the side of the main device. The branched optical signal propagates through the two optical fiber transmission lines 41 and 42. Therefore, the optical signal detection circuits 34 and 35 also detect the optical signal of the non-operational optical fiber transmission line. Therefore, in FIG. 5, the continuity display circuit 38 obtains the continuity state of the optical signal in each optical fiber transmission line from the optical signal detection circuits 34 and 35 and displays the continuity of the optical fiber transmission line in the non-operational state. Let The display method includes both the lamp display of the device and the display on the computer. The necessity of restoration can be determined by knowing the conduction state of the optical fiber transmission line in the non-operational state.

(Embodiment 4) FIG. 6 shows the system configuration of this embodiment. In the present embodiment, the optical fiber transmission line is duplicated, and optical switches are provided at both ends, and each optical switch is switched according to the information received from the receiving circuit.

In FIG. 6, an optical transmission circuit 13-1, an optical reception circuit 14-1, and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1, an optical switch 21, and a switching control circuit 33, and on the side of the slave device are an optical receiving circuit 15-1, an optical transmitting circuit 16-1, a wavelength multiplex demultiplexer 12, an optical switch 22, and a switching control circuit 3.
6. The operation display circuit 37 is provided.

With such a configuration, the system of this embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Are multiplexed by one optical fiber. Optical switch 2
1 is two optical fiber transmission lines 41 and 4
Select one of the two. The optical signal is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 6, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is the wavelength multiplex demultiplexer 1
It is multiplexed into one optical fiber by 2 and guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. In FIG. 6, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. next,
The optical receiving circuit 1 is demultiplexed by the wavelength multiplex demultiplexer 11.
4-1 is received.

As described above, since the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, a smaller optical loss is realized as compared with the case where the optical coupling / branching circuit is used at both ends. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 6, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in operation. When the optical fiber transmission line 41 is disconnected due to a failure, the optical receiving circuit 15-1 on the slave device side detects the disconnection of the optical signal. The switching control circuit 36 instructs the optical switch 22 to switch based on the received information from the optical receiving circuit 15-1 that the optical signal is disconnected. When the optical switch 22 switches to another optical fiber transmission line 42, the optical signal from the optical transmission circuit 16-1 propagates through the optical fiber transmission line 42 selected by the optical switch 22.
Similarly, the optical receiving circuit 14-1 on the side of the main device also detects disconnection of the optical signal. Optical receiver circuit 14 that the optical signal is disconnected
The switching control circuit 33 instructs the optical switch 21 to switch based on the information received from -1. When the optical switch 21 switches to another optical fiber transmission line 42, the optical transmission circuit 13-1
The optical signal from (1) propagates through the optical fiber transmission line 42 selected by the optical switch 21. The optical receiving circuit 15-1 receives the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 according to the received information from the optical receiving circuit 15-1 that the optical signal is conducted. The optical receiving circuit 14-1 also detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 33 holds the operation of the optical switch 21 based on the received information from the optical receiving circuit 14-1 that the optical signal is conducted. Since the optical signal detection function can be easily added to the optical receiving circuits on the main device side and the slave device side, the received information can be extracted by using this function.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

(Fifth Embodiment) FIG. 7 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, the optical switches are provided at both ends, and the optical switch is switched according to the received information from the optical signal detection circuit that monitors the optical fiber transmission line.

In FIG. 7, an optical transmitter circuit 13-1, an optical receiver circuit 14-1 and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1, an optical switch 21, an optical signal detection circuit 31, and a switching control circuit 33 are provided, and an optical receiving circuit 15-1, an optical transmitting circuit 16-1, a wavelength multiplex demultiplexer 12, and an optical switch 22 are provided on the slave side. , An optical signal detection circuit 34, a switching control circuit 36, and an operation display circuit 37. The optical signal detection circuit 31 detects an optical signal from the slave device side via the optical fiber transmission line 41 or 42. If the optical signal detection circuit 31 can detect the optical signal from the main device side, the optical transmission circuit 13-1
Can be monitored. The optical signal detection circuit 34 detects an optical signal from the main device side via the optical fiber transmission line 41 or 42. If the optical signal detection circuit 34 can detect the optical signal from the slave device side, the optical transmission circuit 16-1
Can be monitored.

In such a configuration, the system of this embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Are multiplexed by one optical fiber. Optical switch 2
1 is two optical fiber transmission lines 41 and 4
Select one of the two. The optical signal is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 7, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is the wavelength multiplex demultiplexer 1
It is multiplexed into one optical fiber by 2 and guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. In FIG. 7, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. next,
The optical receiving circuit 1 is demultiplexed by the wavelength multiplex demultiplexer 11.
4-1 is received.

As described above, the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, so that a smaller optical loss is realized as compared with the case where the optical branching circuits are used at both ends. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 7, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in the operating state. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34 on the slave device side detects the disconnection of the optical signal. The switching control circuit 36 instructs the optical switch 22 to switch based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. When the optical switch 22 switches to another optical fiber transmission line 42, the optical signal from the optical transmission circuit 16-1 propagates through the optical fiber transmission line 42 selected by the optical switch 22.
Similarly, the optical signal detection circuit 31 on the main device side also detects the interruption of the optical signal. The switching control circuit 33 instructs the optical switch 21 to switch based on the detection information from the optical signal detection circuit 31 that the optical signal is disconnected. When the optical switch 21 switches to another optical fiber transmission line 42, the optical transmission circuit 13-1
The optical signal from (1) propagates through the optical fiber transmission line 42 selected by the optical switch 21. The optical signal detection circuit 34 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 34 that the optical signal is conducted. The optical signal detection circuit 31 also detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 33 holds the operation of the optical switch 21 based on the detection information from the optical signal detection circuit 31 that the optical signal is conducted.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

(Sixth Embodiment) FIG. 8 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, and an optical switch is provided at both ends, and the optical switch is switched according to the received information from the optical signal detection circuit that monitors each optical fiber transmission line.

In FIG. 8, an optical transmitter circuit 13-1, an optical receiver circuit 14-1, and a wavelength multiplex demultiplexer 1 are provided on the main device side.
1, an optical switch 21, optical signal detection circuits 31 and 32, and a switching control circuit 33, and an optical receiving circuit 15-on the side of the slave device.
1, an optical transmission circuit 16-1, a wavelength multiplex demultiplexer 12, an optical switch 22, optical signal detection circuits 34 and 35, a switching control circuit 36, and an operation display circuit 37. Optical signal detection circuit 31
And 32 detect an optical signal from the slave device side via the optical fiber transmission lines 41 and 42, respectively. The optical signal detection circuits 31 and 32 can also monitor the optical transmission circuit 13-1 and the optical switch 21 if the optical signals from the main device side can be detected. The optical signal detection circuits 34 and 35 detect optical signals from the main unit side via the optical fiber transmission lines 41 and 42, respectively. If the optical signal detection circuits 34 and 35 can detect the optical signal from the slave device side, the optical transmission circuit 16-1 and the optical switch 22 can be monitored.

With such a configuration, the system of the present embodiment operates as follows. The optical signal from the optical transmission circuit 13-1 on the side of the main device is the wavelength multiplex demultiplexer 11
Are multiplexed by one optical fiber. Optical switch 2
1 is two optical fiber transmission lines 41 and 4
Select one of the two. The optical signal is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 8, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuit 15-1. On the other hand, the optical signal from the optical transmission circuit 16-1 on the slave side is the wavelength multiplex demultiplexer 1
It is multiplexed into one optical fiber by 2 and guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. In FIG. 8, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. next,
The optical receiving circuit 1 is demultiplexed by the wavelength multiplex demultiplexer 11.
4-1 is received.

As described above, the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, so that a smaller optical loss is realized as compared with the case where the optical add / drop circuit is used at both ends. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 8, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in operation. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34 on the slave device side detects the disconnection of the optical signal. The switching control circuit 36 instructs the optical switch 22 to switch based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. When the optical switch 22 switches to another optical fiber transmission line 42, the optical signal from the optical transmission circuit 16-1 propagates through the optical fiber transmission line 42 selected by the optical switch 22.
Similarly, the optical signal detection circuit 31 on the main device side also detects the interruption of the optical signal. The switching control circuit 33 instructs the optical switch 21 to switch based on the detection information from the optical signal detection circuit 31 that the optical signal is disconnected. When the optical switch 21 switches to another optical fiber transmission line 42, the optical transmission circuit 13-1
The optical signal from (1) propagates through the optical fiber transmission line 42 selected by the optical switch 21. The optical signal detection circuit 35 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 35 that the optical signal is conducted. The optical signal detection circuit 32 also detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 33 holds the operation of the optical switch 21 based on the detection information from the optical signal detection circuit 31 that the optical signal is conducted.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

(Embodiment 7) FIG. 9 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end and an optical switch is provided at the other end, and the optical switch is switched according to the information received from the receiving circuit.

In FIG. 9, optical transmission circuits 13-1 and 13-2, optical reception circuits 14-1 and 14-2, are provided on the main device side.
The wavelength multiplex demultiplexer 11 and the optical multiplexer / demultiplexer 23 are provided, and the optical receiver circuits 15-1 and 15-2, the optical transmission circuits 16-1 and 16-2, and the wavelength multiplex demultiplexer 12 are provided on the slave device side. , An optical switch 22, a switching control circuit 36, an operation display circuit 37, and a transmission display circuit 39. Optical transmission circuits 13-1, 13-2,
16-1 and 16-2 are optical receiving circuits 15-1 and 1-1 respectively.
It faces 5-2, 14-1, 14-2.

With such a configuration, the system of this embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed into one optical fiber by the wavelength multiplex demultiplexer 11, and the two optical fiber transmission lines are multiplexed by the optical add / drop circuit 23. 41 and 4
It is branched to 2. The optical signal propagating through the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 16-2 on the slave side
The optical signal from (1) is multiplexed into one optical fiber by the wavelength division multiplexing demultiplexer 12, and is guided to either of the two optical fiber transmission lines 41 or 42 by the optical switch 22. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 via the optical coupling / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuits 14-1 and 14-2.

As described above, since the optical switch provided at one end is switched to communicate with only one optical fiber transmission line, even if there is a distance difference between both optical fiber transmission lines, the jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 9, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in the operating state. This optical fiber transmission line 4
When 1 is disconnected due to a failure, the optical receiving circuit 15-1,
15-2 detects the disconnection of the optical signal. The switching control circuit 36 instructs switching of the optical switch 22 based on the received information from the optical receiving circuits 15-1 and 15-2 that the optical signal is disconnected. The optical switch 22 selects another optical fiber transmission line 42. The optical receiving circuits 15-1 and 15-2 receive the optical signal propagating through the optical fiber transmission line 42 and detect the continuity of the optical signal. Optical receiver circuit 1 that the optical signal is conducted
The switching control circuit 36 holds the operation of the optical switch 22 in accordance with the information received from 5-1 and 15-2. Since the function of detecting an optical signal can be easily added to the optical receiving circuit on the side of the slave device, the received information can be extracted by using this function. Since the optical signals from the optical transmission circuits 16-1 and 16-2 propagate through the optical fiber transmission line selected by the optical switch 22, the optical reception circuits 14-1 and 14-2 also detect the optical signals. When the switching control circuit 36 performs switching control with a protection time for interruption or conduction of an optical signal, stable operation is ensured even when the optical fiber transmission path is instantaneously interrupted or when the optical fiber transmission path is switched. be able to.

The switching control circuit 36 may judge the disconnection or conduction of the optical signal based on the logical product of the information received from a plurality of optical receiving circuits, or only the information received from any one optical receiving circuit. You may judge.

Although an example of two sets of bidirectional optical fiber transmission systems has been described here, the present invention is applicable regardless of the number of sets of wavelength-division bidirectional optical fiber transmission systems. In addition, if there is at least one unidirectional optical fiber transmission system from the master device to the slave device, the other optical fiber transmission systems are unidirectional optical fiber transmission systems from the master device to the slave device or from the slave device to the master device. It may be a system.

In the present embodiment, each of the plurality of slave devices receives the optical transmission signal from the corresponding master device. When a plurality of master devices are installed remotely, when a communication failure occurs, there is a case where the slave devices want to know which optical transmission circuit has a failure. Therefore, in FIG. 9, the reception information from the optical receiver circuits 15-1 and 15-2 of the plurality of slave devices is collected, and the transmission display circuit 39 displays the state of the optical transmitter circuit of the main device. The display method includes both the lamp display of the device and the display on the computer. With this transmission display circuit, the states of the optical transmission circuits on the side of the plurality of main devices can be known on the side of the plurality of slave devices. Similarly in the following embodiments, the states of the optical transmission circuits on the side of the plurality of main devices can be known on the side of the plurality of slave devices by displaying on the transmission display circuit.

(Embodiment 8) FIG. 10 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end and an optical switch is provided at the other end, and the optical information is received by the optical signal detection circuit that monitors the optical fiber transmission line. Switch the switch.

In FIG. 10, optical transmitter circuits 13-1 and 13-2 and optical receiver circuits 14-1 and 14- are provided on the main device side.
2, equipped with a wavelength multiplex demultiplexer 11 and an optical coupling / branching circuit 23,
On the side of the slave device are optical receiving circuits 15-1 and 15-2, optical transmitting circuits 16-1 and 16-2, a wavelength multiplex demultiplexer 12, an optical switch 22, an optical signal detection circuit 34, and a switching control circuit 36. ,
The operation display circuit 37 and the transmission display circuit 39 are provided. The optical transmission circuits 13-1, 13-2, 16-1, 16-2 are optical reception circuits 15-1, 15-2, 14-1, 14-2, respectively.
To face. The optical signal detection circuit 34 detects an optical signal from the main device side via the optical fiber transmission line 41 or 42. If the optical signal detection circuit 34 can detect the optical signal from the slave device side, the optical transmission circuits 16-1 and 16 can be used.
-2 can be monitored.

With such a configuration, the system of the present embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed into one optical fiber by the wavelength multiplex demultiplexer 11, and the two optical fiber transmission lines are multiplexed by the optical add / drop circuit 23. 41 and 4
It is branched to 2. The optical signal propagating through the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 16-2 on the slave side
The optical signal from (1) is multiplexed into one optical fiber by the wavelength division multiplexing demultiplexer 12, and is guided to either of the two optical fiber transmission lines 41 or 42 by the optical switch 22. The optical signal propagated through one of the two optical fiber transmission lines is guided to the wavelength multiplex demultiplexer 11 via the optical coupling / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuits 14-1 and 14-2. The optical signal detection circuit 34 is inserted between the optical switch 22 and the optical multiplexer / demultiplexer 12, and detects the optical signals from the optical transmission circuits 13-1 and 13-2 on the main device side.

As described above, since the communication is performed only by one optical fiber transmission line by switching the optical switch provided at one end, even if there is a distance difference between both optical fiber transmission lines, the jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 10, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in the operating state. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34
Detects a break in the optical signal. The switching control circuit 36 instructs the switching of the optical switch 22 based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. The optical switch 22 selects another optical fiber transmission line 42. The optical signal detection circuit 34 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. According to the detection information from the optical signal detection circuit 34 that the optical signal is conducted,
The switching control circuit 36 holds the operation of the optical switch 22.
The optical signal detection circuit 34 monitors a part of the optical signals from the optical transmission circuits 13-1 and 13-2.
The optical signals from -1, 13-2 are not greatly attenuated. Since the optical signals from the optical transmission circuits 16-1 and 16-2 propagate through the optical fiber transmission line selected by the optical switch 22, the optical reception circuits 14-1 and 14-2 also detect the optical signals. When the switching control circuit 36 performs switching control with a protection time against disconnection or continuity of the optical signal, stable operation is secured against both instantaneous interruption of the optical fiber transmission line and switching of the optical fiber transmission line. can do. In this embodiment,
Since the information received from the optical receiver circuit is not used, the optical fiber transmission line switching control is performed even before the optical receiver circuit on the slave device side becomes an obstacle or before the optical receiver circuit of the slave device is installed. be able to.

The switching control circuit 36 may judge the disconnection or conduction of the optical signal by detecting the optical signals from the plurality of optical transmitting circuits, or detecting the optical signal from any one of the optical transmitting circuits. You may judge just by doing.

Although an example of two sets of bidirectional optical fiber transmission systems has been described here, the present invention can be applied regardless of the number of sets of wavelength-division bidirectional optical fiber transmission systems. In addition, if there is at least one unidirectional optical fiber transmission system from the master device to the slave device, the other optical fiber transmission systems are unidirectional optical fiber transmission systems from the master device to the slave device or from the slave device to the master device. It may be a system.

(Ninth Embodiment) FIG. 11 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, an optical coupling / branching circuit is provided at one end, and an optical switch is provided at the other end. To switch the optical switch.

In FIG. 11, the optical transmitter circuits 13-1 and 13-2 and the optical receiver circuits 14-1 and 14- are provided on the main device side.
2, equipped with a wavelength multiplex demultiplexer 11 and an optical coupling / branching circuit 23,
On the side of the slave device are optical receiving circuits 15-1 and 15-2, optical transmitting circuits 16-1 and 16-2, a wavelength multiplex demultiplexer 12, an optical switch 22, optical signal detection circuits 34 and 35, and switching control. The circuit 36, the operation display circuit 37, the continuity display circuit 38, and the transmission display circuit 39 are provided. Optical transmitter circuits 13-1, 13-2, 1
Reference numerals 6-1 and 16-2 denote optical receiving circuits 15-1 and 15 respectively.
-2, 14-1, and 14-2 are opposed. The optical signal detection circuits 34 and 35 detect optical signals from the main unit side via the optical fiber transmission lines 41 and 42, respectively. If the optical signal detection circuits 34 and 35 can detect the optical signals from the slave device side, respectively, the optical transmission circuits 16-1 and 16- will be provided.
2 and the optical switch 22 can be monitored.

With such a configuration, the system of the present embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed into one optical fiber by the wavelength multiplex demultiplexer 11, and the two optical fiber transmission lines are multiplexed by the optical add / drop circuit 23. 41 and 4
It is branched to 2. 2 propagated through two optical fiber transmission lines
The two optical signals are guided to the wavelength division multiplexer 12 by the optical switch 22 on the slave side. Next, the wavelength multi-polymerization demultiplexer 12
Are demultiplexed by and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 1 on the slave side
The optical signal from 6-2 is multiplexed into one optical fiber by the wavelength multiplexing / multiplexing demultiplexer 12 and guided to either of the two optical fiber transmission lines 41 or 42 by the optical switch 22. . 1 of 2 optical fiber transmission lines
The optical signal propagating through the optical fiber transmission line of the book is guided to the wavelength multiplex demultiplexer 11 via the optical combining / branching circuit 23 on the main device side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 11 and received by the optical receiving circuits 14-1 and 14-2. The optical signal detection circuit 34 includes the optical fiber transmission line 41 and the optical switch 2
2, the optical signal detection path 35 is connected to the optical fiber transmission path 42.
And the optical switch 22 respectively, and detects the optical signals from the optical transmission circuits 13-1 and 13-2 on the main device side.

As described above, since the communication is performed only by one optical fiber transmission line by switching the optical switch provided at one end, even if there is a distance difference between both optical fiber transmission lines, the jitter in the optical receiving circuit Can be avoided. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 11, since the optical fiber transmission line 41 is selected by the optical switch 22, the optical fiber transmission line 41 is in the operating state. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34
Detects a break in the optical signal. The switching control circuit 36 instructs the switching of the optical switch 22 based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. The optical switch 22 switches to another optical fiber transmission line 42. After the switching of the optical switch 22, the optical signal detection circuit 35 has already detected the conduction of the optical signal. The optical switch 22 may instruct to switch to the optical fiber transmission path 42 after waiting for the detection information from the optical signal detection circuit 35 that the optical signal is conducting. Based on the detection information from the optical signal detection circuit 35 that the optical signal is conducting, the switching control circuit 36
Holds the operation of the optical switch 22. The optical signal detection circuit may stop its operation when the optical fiber transmission line is in a non-operational state. In this case, power consumption can be reduced. The optical signal detection circuit may keep operating even when the optical fiber transmission line is in a non-operational state. In this case, the conduction state of the optical signal can be constantly monitored.

The optical signal detection circuits 34 and 35 are the optical transmission circuit 1
Since a part of the optical signals from 3-1 and 13-2 is monitored, the optical signals from the optical transmission circuits 13-1 and 13-2 are not greatly attenuated. Optical transmitter circuits 16-1, 16-2
Since the optical signal from the optical fiber propagates through the optical fiber transmission path selected by the optical switch 22, the optical receiving circuits 14-1 and 14-2
Also detects the optical signal. When the switching control circuit 36 performs switching control with a protection time for interruption or conduction of the optical signal,
Stable operation can be ensured even when the optical fiber transmission line is interrupted or when the optical fiber transmission line is switched. In this embodiment, since the received information from the optical receiving circuit is not used, the optical fiber transmission is performed even before the optical receiving circuit of the slave device becomes an obstacle or before the optical receiving circuit of the slave device is installed. Road switching control can be performed. Furthermore, since two optical fiber transmission lines can be monitored simultaneously,
It is also possible to monitor the conduction state of the optical fiber transmission line in the non-operational state.

The switching control circuit 36 may judge the interruption or conduction of the optical signal by detecting the optical signals from the plurality of optical transmitting circuits, or detecting the optical signal from any one of the optical transmitting circuits. You may judge just by doing.

Although an example of two sets of bidirectional optical fiber transmission systems has been described here, the present invention can be applied regardless of the number of sets of wavelength-division bidirectional optical fiber transmission systems. In addition, if there is at least one unidirectional optical fiber transmission system from the master device to the slave device, the other optical fiber transmission systems are unidirectional optical fiber transmission systems from the master device to the slave device or from the slave device to the master device. It may be a system.

Furthermore, in the present embodiment, since two optical fiber transmission lines can be monitored at the same time, it is also possible to monitor the conduction state of the optical fiber transmission line in the non-operational state. If one of the two optical fiber transmission lines is in the operating state and it is possible to know whether or not the other optical fiber transmission line is conducting, maintainability is improved. If there is a non-conduction state, the optical fiber transmission line must be restored. In the conductive state, even if a failure occurs in one, communication can be restored by switching to the other. In the present embodiment, an optical add / drop circuit is used on the side of the main device to branch the optical signal from the side of the main device. The branched optical signal propagates through the two optical fiber transmission lines 41 and 42. Therefore, the optical signal detection circuits 34 and 35 also detect the optical signal of the non-operational optical fiber transmission line. Therefore, in FIG. 11, the continuity display circuit 38 obtains the continuity of the optical signal in each optical fiber transmission line from the optical signal detection circuits 34 and 35, and displays the continuity of the optical fiber transmission line in the non-operational state. Let The necessity of restoration can be determined by knowing the conduction state of the optical fiber transmission line in the non-operational state.

(Embodiment 10) FIG. 12 shows the system configuration of the present embodiment. In the present embodiment, the optical fiber transmission line is duplicated, and optical switches are provided at both ends, and each optical switch is switched according to the information received from the receiving circuit.

In FIG. 12, the optical transmitter circuits 13-1 and 13-2 and the optical receiver circuits 14-1 and 14- are provided on the main device side.
2, a wavelength multiplex demultiplexer 11, an optical switch 21, and a switching control circuit 33 are provided, and an optical receiving circuit 15-1 is provided on the slave side.
15-2, the optical transmission circuits 16-1 and 16-2, the wavelength multiplex demultiplexer 12, the optical switch 22, the switching control circuit 36, the operation display circuit 37, and the transmission display circuit 39. The optical transmission circuits 13-1, 13-2, 16-1, 16-2 face the optical reception circuits 15-1, 15-2, 14-1, 14-2, respectively.

With such a configuration, the system of the present embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed by the wavelength multiplex demultiplexer 11 into one optical fiber. The optical switch 21 selects one of the two optical fiber transmission lines 41 and 42. The optical signal is
It is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 12, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 16-2 on the slave side
The optical signal from is multiplexed into one optical fiber by the wavelength division multiplexing demultiplexer 12, and is guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. . In FIG. 12, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. Next, the light is multiplexed by the wavelength multiplex demultiplexer 11, and the optical receiving circuits 14-1 and 14-2 are used.
Will be received at.

As described above, the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, so that an optical loss smaller than that using the optical add / drop circuit at both ends is realized. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 12, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in the operating state. When the optical fiber transmission line 41 is disconnected due to a failure, the optical receiving circuits 15-1 and 15-2 on the slave device side detect the disconnection of the optical signal. Optical receiving circuits 15-1 and 15 that the optical signal is disconnected
-2, the switching control circuit 36 instructs the optical switch 22 to perform switching. When the optical switch 22 switches to another optical fiber transmission line 42, the optical transmission circuit 16-
The optical signals from 1 and 16-2 propagate through the optical fiber transmission line 42 selected by the optical switch 22. Similarly, the optical receiver circuits 14-1 and 14-2 on the main device side also detect the interruption of the optical signal. The optical receiving circuit 14-1 that the optical signal is disconnected,
The switching control circuit 33 receives the information from 14-2.
The optical switch 21 is instructed to switch. When the optical switch 21 switches to another optical fiber transmission line 42, the optical transmission circuit 13
The optical signals from -1, 13-2 propagate through the optical fiber transmission path 42 selected by the optical switch 21. Optical receiver circuit 15
-1, 15-2 receive the optical signal propagating through the optical fiber transmission line 42 and detect the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 according to the received information from the optical receiving circuits 15-1 and 15-2 that the optical signal is conducted. The optical receiver circuits 14-1 and 14-2 also detect the optical signal propagating through the optical fiber transmission line 42 and detect the continuity of the optical signal. The switching control circuit 33 holds the operation of the optical switch 21 according to the received information from the optical receiving circuits 14-1 and 14-2 that the optical signal is conducted. Since the optical signal detection function can be easily added to the optical receiving circuits on the main device side and the slave device side, the received information can be extracted by using this function.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

The switching control circuit 33 or 36 may judge the disconnection or conduction of the optical signal based on the logical product of the information received from a plurality of optical receiving circuits, or the information received from any one optical receiving circuit. You may judge it only.

Although an example of two sets of bidirectional optical fiber transmission systems has been described here, the present invention is applicable regardless of the number of sets of bidirectional optical fiber transmission systems for wavelength multiplexing. In addition, if there is at least one unidirectional optical fiber transmission system from the master device to the slave device, the other optical fiber transmission systems are unidirectional optical fiber transmission systems from the master device to the slave device or from the slave device to the master device. It may be a system.

(Embodiment 11) FIG. 13 shows the system configuration of this embodiment. In the present embodiment, the optical fiber transmission line is duplicated, the optical switches are provided at both ends, and the optical switch is switched according to the received information from the optical signal detection circuit that monitors the optical fiber transmission line.

In FIG. 13, optical transmitter circuits 13-1 and 13-2 and optical receiver circuits 14-1 and 14- are provided on the main device side.
2. The wavelength multiplex demultiplexer 11, the optical switch 21, the optical signal detection circuit 31, and the switching control circuit 33 are provided, and the optical reception circuits 15-1 and 15-2 and the optical transmission circuit 16-1 are provided on the slave device side. ,
16-2, wavelength multiplex demultiplexer 12, optical switch 22, optical signal detection circuit 34, switching control circuit 36, operation display circuit 3
7. A transmission display circuit 39 is provided. Optical transmission circuit 13-1,
Reference numerals 13-2, 16-1 and 16-2 denote the optical receiving circuit 1 respectively.
It faces 5-1, 15-2, 14-1, 14-2. The optical signal detection circuit 31 detects an optical signal from the slave device side via the optical fiber transmission line 41 or 42. The optical signal detection circuit 31 can also monitor the optical transmission circuits 13-1 and 13-2 if the optical signal from the main device side can be detected. The optical signal detection circuit 34 detects an optical signal from the main device side via the optical fiber transmission line 41 or 42.
The optical signal detection circuit 34 can also monitor the optical transmission circuits 16-1 and 16-2 if the optical signal from the slave device side can be detected.

With such a configuration, the system of this embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed by the wavelength multiplex demultiplexer 11 into one optical fiber. The optical switch 21 selects one of the two optical fiber transmission lines 41 and 42. The optical signal is
It is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 13, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 16-2 on the slave side
The optical signal from is multiplexed into one optical fiber by the wavelength division multiplexing demultiplexer 12, and is guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. . In FIG. 13, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. Next, the light is multiplexed by the wavelength multiplex demultiplexer 11, and the optical receiving circuits 14-1 and 14-2 are used.
Will be received at.

As described above, the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, so that a smaller optical loss is realized as compared with the case where the optical add / drop circuit is used at both ends. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 13, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in operation. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34 on the slave device side detects the disconnection of the optical signal. The switching control circuit 36 instructs the optical switch 22 to switch based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. When the optical switch 22 switches to another optical fiber transmission line 42, the optical signals from the optical transmission circuits 16-1 and 16-2 are transmitted to the optical fiber transmission line 42 selected by the optical switch 22.
Propagate. Similarly, the optical signal detection circuit 31 on the main device side also detects the interruption of the optical signal. The switching control circuit 33 instructs the optical switch 21 to switch based on the detection information from the optical signal detection circuit 31 that the optical signal is disconnected. When the optical switch 21 switches to another optical fiber transmission line 42, the optical signals from the optical transmission circuits 13-1 and 13-2 are transmitted to the optical switch 2
1 propagates through the optical fiber transmission line 42 selected. The optical signal detection circuit 34 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 34 that the optical signal is conducted. The optical signal detection circuit 31 also detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal.
The switching control circuit 33 holds the operation of the optical switch 21 based on the detection information from the optical signal detection circuit 31 that the optical signal is conducted.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

The switching control circuit 33 or 36 may judge the disconnection or conduction of the optical signal by detecting the optical signals from the plurality of optical transmitting circuits, or by determining the optical signal from any one optical transmitting circuit. The determination may be made only by detecting

Although an example of two sets of bidirectional optical fiber transmission systems has been described here, the present invention is applicable regardless of the number of sets of bidirectional optical fiber transmission systems for wavelength multiplexing. If there is at least one unidirectional optical fiber transmission system from the master device to the slave device and at least one unidirectional optical fiber transmission system from the slave device to the master device, the other optical fiber transmission system is It may be a one-way optical fiber transmission system from the master device to the slave device or from the slave device to the master device.

(Embodiment 12) FIG. 14 shows the system configuration of this embodiment. In the present embodiment, the optical fiber transmission line is duplicated, and an optical switch is provided at both ends, and the optical switch is switched according to the received information from the optical signal detection circuit that monitors each optical fiber transmission line.

In FIG. 14, the optical transmitter circuits 13-1 and 13-2 and the optical receiver circuits 14-1 and 14- are provided on the main device side.
2, the wavelength multiplex demultiplexer 11, the optical switch 21, the optical signal detection circuits 31 and 32, and the switching control circuit 33, and the optical receiving circuits 15-1 and 15-2 and the optical transmission circuit 16 on the slave side.
-1, 16-2, wavelength multiplex demultiplexer 12, optical switch 2
2. The optical signal detection circuits 34 and 35, the switching control circuit 36, the operation display circuit 37, and the transmission display circuit 39 are provided. The optical transmission circuits 13-1, 13-2, 16-1, 16-2 face the optical reception circuits 15-1, 15-2, 14-1, 14-2, respectively. The optical signal detection circuits 31 and 32 detect optical signals from the slave device side via the optical fiber transmission lines 41 and 42, respectively. If the optical signal detection circuits 31 and 32 can detect the optical signal from the main device side, the optical transmission circuits 13-1 and 13-2 and the optical switch 21 can be monitored. The optical signal detection circuits 34 and 35 detect optical signals from the main unit side via the optical fiber transmission lines 41 and 42, respectively. If the optical signal detection circuits 34 and 35 can detect the optical signal from the slave device side, the optical transmission circuit 16-
It is also possible to monitor 1, 16-2 and the optical switch 22.

With such a configuration, the system of this embodiment operates as follows. The optical signals from the optical transmission circuits 13-1 and 13-2 on the side of the main device are multiplexed by the wavelength multiplex demultiplexer 11 into one optical fiber. The optical switch 21 selects one of the two optical fiber transmission lines 41 and 42. The optical signal is
It is guided to the optical fiber transmission line selected by the optical switch 21. In FIG. 14, the optical fiber transmission line 41 is selected. The optical signal propagating through the selected optical fiber transmission line is guided to the wavelength multiplex demultiplexer 12 by the optical switch 22 on the slave side. Next, it is demultiplexed by the wavelength multiplex demultiplexer 12 and received by the optical receiving circuits 15-1 and 15-2. On the other hand, the optical transmission circuits 16-1 and 16-2 on the slave side
The optical signal from is multiplexed into one optical fiber by the wavelength division multiplexing demultiplexer 12, and is guided to one of the two optical fiber transmission lines 41 and 42 selected by the optical switch 22. . In FIG. 14, the optical fiber transmission line 41 is selected. The optical signal propagating through the optical fiber transmission line is guided to the wavelength multiplex demultiplexer 11 via the optical switch 21 on the main device side. Next, the light is multiplexed by the wavelength multiplex demultiplexer 11, and the optical receiving circuits 14-1 and 14-2 are used.
Will be received at.

As described above, the optical switch is used on both the main device side and the slave device side to select the optical fiber transmission line, so that a smaller optical loss is realized as compared with the case where the optical add / drop circuit is used at both ends. it can. Further, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a difference in distance between the two optical fiber transmission lines. Since the difference in distance does not matter, it is possible to use optical fiber transmission lines laid on different routes.

In FIG. 14, since the optical fiber transmission line 41 is selected by the optical switches 21 and 22, the optical fiber transmission line 41 is in the operating state. When the optical fiber transmission line 41 is disconnected due to a failure, the optical signal detection circuit 34 on the slave device side detects the disconnection of the optical signal. The switching control circuit 36 instructs the optical switch 22 to switch based on the detection information from the optical signal detection circuit 34 that the optical signal is disconnected. When the optical switch 22 switches to another optical fiber transmission line 42, the optical signals from the optical transmission circuits 16-1 and 16-2 are transmitted to the optical fiber transmission line 42 selected by the optical switch 22.
Propagate. Similarly, the optical signal detection circuit 31 on the main device side also detects the interruption of the optical signal. The switching control circuit 33 instructs the optical switch 21 to switch based on the detection information from the optical signal detection circuit 31 that the optical signal is disconnected. When the optical switch 21 switches to another optical fiber transmission line 42, the optical signals from the optical transmission circuits 13-1 and 13-2 are transmitted to the optical switch 2
1 propagates through the optical fiber transmission line 42 selected. The optical signal detection circuit 35 detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal. The switching control circuit 36 holds the operation of the optical switch 22 based on the detection information from the optical signal detection circuit 35 that the optical signal is conducted. The optical signal detection circuit 32 also detects the optical signal propagating through the optical fiber transmission line 42 and detects the continuity of the optical signal.
The switching control circuit 33 holds the operation of the optical switch 21 based on the detection information from the optical signal detection circuit 31 that the optical signal is conducted.

In the above operation, the two switching control circuits 3
Since 3 and 36 are configured to autonomously determine switching, it is possible to eliminate the need for a switching signal transfer line for synchronizing the switching control circuits with each other. The switching control circuit 33,
When the switching control is performed with a protection time for the interruption or conduction of the optical signal 36, stable operation can be secured against both instantaneous interruption and switching.

The switching control circuit 33 or 36 may judge the disconnection or conduction of the optical signal by detecting the optical signals from a plurality of optical transmission circuits, or by determining the optical signal from any one optical transmission circuit. The determination may be made only by detecting

Here, an example of two sets of bidirectional optical fiber transmission systems has been described, but the present invention is applicable regardless of the number of sets of wavelength-division bidirectional optical fiber transmission systems. If there is at least one unidirectional optical fiber transmission system from the master device to the slave device and at least one unidirectional optical fiber transmission system from the slave device to the master device, the other optical fiber transmission system is It may be a one-way optical fiber transmission system from the master device to the slave device or from the slave device to the master device.

(Embodiment 13) In the optical fiber transmission system in which the optical fiber transmission line is duplicated, the optical switches are provided at both ends, and the optical switches are autonomously switched, the optical switches at both ends are independently switched. If the switching timing and the like are not specified, both optical fibers switch to different optical fiber transmission lines, and in the worst case, both optical switches repeat switching. In the present embodiment, the switching timing is specified to avoid the worst situation.

FIG. 15 is an explanation of general switching timing. In FIG. 15, the optical fiber transmission line 41
When the optical signal is disconnected while being connected to, the optical signal disconnection is detected after a predetermined time (interruption detection time) from the optical signal disconnection. Even if the disconnection of the optical signal is detected, the optical switch is switched after a certain time (interruption protection time) in order to prevent the influence of the instantaneous disconnection of the optical fiber. It takes a certain time (switching time) to switch the optical switch. When the optical signal is already conducted to the optical fiber transmission line 42, the conduction of the optical signal is detected after a fixed time (conduction detection time) after the switching. Even if the conduction of the optical signal is detected, it is determined that the optical signal is conducted after a certain time (conduction protection time) in order to prevent malfunction. When the conduction of the optical signal is detected within the break protection time, the conduction protection time starts. When the disconnection of the optical signal is detected within the continuity protection time, the disconnection detection time starts.
When the optical fiber transmission line is switched, the disconnection protection time starts from the beginning. Although the disconnection protection time and the continuity protection time are provided here, the setting of either or both times may be omitted in order to speed up the determination.

FIG. 16 shows the timing from the moment when the main device side and the slave device side switch to different optical fiber transmission lines. As shown in FIG. 16, after the optical switch is switched between the main device side and the slave device side, the time until the determination of the interruption of the optical signal (disconnection protection time) and the optical switch after the determination are made. Timing is provided such that the total time until switching (switching time) is different. In FIG.
The total of the disconnection protection time and the switching time of the slave device is set longer than the total of the disconnection protection time and the switching time of the master device side. If it is difficult to change the switching time setting of the optical switch,
It is also possible to adjust the disconnection protection time. With this setting, there is a timing for switching to the same optical fiber transmission line on the main device side and the slave device side.

Even if the main device side and the slave device side are switched to the same optical fiber transmission line, there is a possibility that the optical fiber transmission line may be switched depending on the timing or when it is judged that the optical signal is interrupted. . Therefore, it is easy to detect the continuity of the optical signal. On the main unit side and the slave unit side, the time from the detection of the optical signal disconnection to the judgment of the optical signal disconnection (interruption protection time) is the optical signal conduction after the optical switch is switched. The timing is set to be longer than the time until the determination (total of conduction detection time and conduction protection time). With this setting, one device
Before the optical switch switches the optical fiber transmission line after the disconnection protection time elapses, the opportunity for the other device to switch to the same optical fiber transmission line increases.

[0115]

As described above, according to the present invention,
By switching the optical switch provided at one end, communication is performed using only one optical fiber transmission line, so that it is possible to avoid jitter in the optical receiving circuit even if there is a distance difference between both optical fiber transmission lines. Further, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use optical fiber transmission lines laid on different routes.

As described above, according to the present invention, the optical switches provided at both ends are used to select the optical fiber transmission line, so that the optical loss is smaller than that when the optical add / drop circuit is used at both ends. it can. In addition, since communication is performed using only one optical fiber transmission line, it is possible to avoid jitter in the optical receiving circuit even if there is a distance difference between both optical fiber transmission lines.
Furthermore, since the difference in distance between the two optical fiber transmission lines does not pose a problem, it is possible to use the optical fiber transmission lines laid on different routes. Further, in the present invention, since the two switching control circuits are configured to autonomously determine switching,
A transfer line for a switching signal for synchronizing the switching control circuits with each other can be eliminated.

[Brief description of drawings]

FIG. 1 is a configuration example of a conventional optical fiber transmission system.

FIG. 2 is another configuration example of a conventional optical fiber transmission system.

FIG. 3 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 4 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 5 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 6 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 7 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 8 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 9 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 10 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 11 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 12 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 13 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 14 is a configuration example of an optical fiber transmission system of the present invention.

FIG. 15 is a diagram for explaining the timing from the moment when the main device side and the slave device side switch to different optical fiber transmission lines.

FIG. 16 is a diagram illustrating switching control of an optical fiber transmission line according to the present invention.

[Explanation of symbols]

11: Wavelength multiplex demultiplexer 12: Wavelength multiplex demultiplexer 13-1, 13-2: Optical transmission circuit 14-1, 14-2: Optical receiver circuit 15-1, 15-2: Optical receiver circuit 16-1, 16-2: Optical transmission circuit 21: Optical switch 22: Optical switch 23: Optical branching circuit 31: Optical signal detection circuit 32: Optical signal detection circuit 33: Switching control circuit 34: Optical signal detection circuit 35: Optical signal detection circuit 36: Switching control circuit 37: Operation display circuit 38: Continuity display circuit 39: Transmission display circuit 41: Optical fiber transmission line 42: Optical fiber transmission line

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akio Yamaguchi             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Toshihiko Sugie             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5K102 AA15 AA44 AD01 AL13 LA26                       LA46 PD13 PH47 PH48 PH49

Claims (17)

[Claims] 1. In an optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a main unit and a slave unit by means of a single-core optical fiber, an optical coupling system for branching optical signals in a one-to-two relationship on the side of the main unit. A branch circuit is provided, and an optical switch for selecting one route from two routes is provided on the side of the slave device, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission lines. An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to information received from an optical receiving circuit of a slave device. 2. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein an optical signal for branching an optical signal in a one-to-two relationship is provided on the main device side. A branch circuit is provided, and an optical switch for selecting one route from two routes is provided on the side of the slave device, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission lines. An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to detection information from an optical signal detection circuit installed between the optical switch and the slave device. 3. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein an optical signal for branching an optical signal in a one-to-two relationship is provided on the main device side. A branch circuit is provided, an optical switch for selecting one path from two paths is provided on the side of the slave device, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission lines, An optical fiber transmission system comprising a switching control circuit for switching the optical switches according to detection information from optical signal detection circuits inserted between the two optical fiber transmission lines and the optical switch. 4. In an optical fiber transmission system for performing wavelength division multiplexing bidirectional transmission between a master device and a slave device by means of a single-core optical fiber, two routes are provided to each of the master device side and the slave device side. An optical switch for selecting one route is provided, the two optical switches are connected by two optical fiber transmission lines, and an optical switch on the side of the main device is provided according to information received from the optical receiving circuit of the main device. And a switching control circuit for switching an optical switch on the side of the slave device according to received information from the optical receiving circuit of the slave device. 5. An optical fiber transmission system for performing wavelength division multiplexing bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein two routes are provided to each of the main device side and the slave device side. An optical switch for selecting one path is provided, and the two optical switches are connected by two optical fiber transmission lines, and an optical switch installed between the optical switch on the side of the main device and the main device. A switching control circuit that switches an optical switch on the side of the main device according to detection information from a signal detection circuit, and detection information from an optical signal detection circuit installed between the optical switch on the side of the slave device and the slave device. And a switching control circuit for switching the optical switch on the side of the slave device. 6. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a main device and a slave device by means of a single-core optical fiber, wherein two routes are provided to each of the main device side and the slave device side. An optical switch for selecting one route is provided, and the two optical switches are connected by two optical fiber transmission lines, and between the two optical fiber transmission lines and the optical switch on the side of the main device. A switching control circuit for switching the optical switch on the side of the main device according to the detection information from the inserted optical signal detection circuit, and a switching control circuit inserted between the two optical fiber transmission lines and the optical switch on the side of the slave device. And a switching control circuit for switching the optical switch on the slave device side according to the detection information from the optical signal detection circuit. 7. One between a plurality of master devices and a plurality of slave devices
In an optical fiber transmission system that performs wavelength-division-multiplexed bidirectional transmission using a core optical fiber, an optical add / drop circuit for adding / dropping an optical signal in a one-to-two relationship is provided on the side of the plurality of main devices, and on the side of the plurality of slave devices. Is provided with an optical switch for selecting one path from two paths, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission paths, and the optical receiving circuits of the plurality of slave devices are connected to each other. An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to received information. 8. One between a plurality of master devices and a plurality of slave devices
In an optical fiber transmission system that performs wavelength-division-multiplexed bidirectional transmission using a core optical fiber, an optical add / drop circuit for adding / dropping an optical signal in a one-to-two relationship is provided on the side of the plurality of main devices, and on the side of the plurality of slave devices. Is provided with an optical switch for selecting one route from two routes, the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission lines, and the optical switch and the plurality of slave devices are connected to each other. An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to detection information from an optical signal detection circuit installed in the optical fiber transmission system. 9. One between a plurality of master devices and a plurality of slave devices.
In an optical fiber transmission system that performs wavelength-division-multiplexed bidirectional transmission using a core optical fiber, an optical add / drop circuit for adding / dropping an optical signal in a one-to-two relationship is provided on the side of the plurality of main devices, and on the side of the plurality of slave devices. Includes an optical switch for selecting one path from two paths, and the optical coupling / branching circuit and the optical switch are connected by two optical fiber transmission paths, and the two optical fiber transmission paths and the optical switch. An optical fiber transmission system comprising a switching control circuit for switching the optical switch according to detection information from an optical signal detection circuit inserted between the optical fiber transmission systems. 10. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission using a one-core optical fiber between a plurality of main devices and a plurality of slave devices. Each side is equipped with an optical switch that selects one of the two routes, and there is a two switch between the two optical switches.
A switching control circuit connected by a plurality of optical fiber transmission lines and switching optical switches on the side of the plurality of main devices according to reception information from each optical receiving circuit of the plurality of main devices; An optical fiber transmission system, comprising: a switching control circuit that switches an optical switch on the side of the slave device according to information received from the receiving circuit. 11. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by means of a one-core optical fiber, wherein the plurality of main devices are connected to the plurality of slave devices. Each side is equipped with an optical switch that selects one of the two routes, and there is a two switch between the two optical switches.
Of the plurality of main devices by the detection information from the optical signal detection circuit connected between the plurality of main devices connected by the optical fiber transmission line of the book A switching control circuit for switching the optical switches, and optical signals on the side of the plurality of slaves based on detection information from an optical signal detection circuit installed between the optical switches on the side of the plurality of slaves and the plurality of slaves. An optical fiber transmission system comprising: a switching control circuit for switching a switch. 12. An optical fiber transmission system for wavelength-division-multiplexed bidirectional transmission between a plurality of main devices and a plurality of slave devices by a one-core optical fiber, wherein the plurality of main devices are connected to the plurality of slave devices. Each side is equipped with an optical switch that selects one of the two routes, and there is a two switch between the two optical switches.
Connected by two optical fiber transmission lines, and the plurality of main devices are detected by detection information from optical signal detection circuits respectively inserted between the two optical fiber transmission lines and the optical switches on the side of the plurality of main devices. Switch control circuit for switching the optical switch on the side of the optical switch and the detection information from the optical signal detection circuit inserted between the two optical fiber transmission lines and the optical switches on the side of the plurality of slave devices, respectively. An optical fiber transmission system comprising: a switching control circuit for switching an optical switch on the side of the slave device. 13. On the side of the main device and the side of the slave in claims 4 to 6, or on the side of the plurality of main devices and the side of the plurality of slaves in claims 10 to 12, 7. The total of the time until it is determined that the optical signal is disconnected after the optical switch is switched and the time until the optical switch is switched after the determination is different from each other.
Or the optical fiber transmission system according to 10 to 12. 14. The optical signal at the side of the master device and the side of the slave device according to claim 4, and the side of the plurality of master devices and the side of the plurality of slave devices according to claim 10 7. The time from the detection of the break to the judgment of the break of the optical signal is longer than the time from the switching of the optical switch to the judgment of the conduction of the optical signal. Or the optical fiber transmission system according to 10 to 12. 15. The transmission display circuit for displaying the status of each of the optical transmission circuits of the plurality of main devices in each of the plurality of slave devices according to any one of claims 7 to 14, wherein: Fiber optic transmission system. 16. The slave device according to claim 3 or the plurality of slave devices according to claim 9, further comprising a continuity display circuit for displaying a continuity state of an optical fiber transmission line in a non-operating state. The optical fiber transmission system according to claim 3 or 9. 17. The slave device according to claim 1,
Alternatively, in the plurality of slave devices according to any one of claims 7 to 12, there is provided an operation display circuit that indicates which of the two optical fiber transmission lines is in an operation state. Fiber optic transmission system.