JPH06209284A - Optical switching module - Google Patents

Abstract

PURPOSE:To obtain an optical switching module which is capable of performing a continuous and stable communication by using a reserve system signal processing module even if an active system signal processing module fails. CONSTITUTION:Four 2X2 optical switch elements 11, 12, 13, 14 are used for the optical switching module 2 within a communication node device 1. As a result, the signals from active system or reserve system optical fibers 31, 32, 33, 34 can be received by either active system or reserve system signal processing modules 3, 4, and, further, the signals from the active system or reserve system signal processing modules 3, 4 can be inserted into either the active system or reserve system optical fibers 31, 32, 33, 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching module for branching, inserting, folding, passing, etc. of an optical transmission line in a communication node device of a duplex ring network using an optical fiber consisting of an active system and a standby system. It is about.

[0002]

2. Description of the Related Art Local Area Network (LAN)
In the ring type network using optical fiber,
In order to secure the reliability of the network against a failure or the like, a signal processing unit in a transmission line or a communication node device is often configured in a dual structure with an active system and a standby system. FIG. 2 shows a configuration of a duplicated communication node device. 1 is a communication node device, 2 is an optical switching module, 3 is an active signal processing module, 4 is a standby signal processing module, and 31 and 32 are The working optical fibers 33 and 34 are standby optical fibers. In normal operation, the received signal from the working optical fiber 32 is branched by the optical switching module 2 to the working signal processing module 3 for processing received signal, or the working signal processing module 3 is used.
By inserting a transmission signal from the optical switching module 2 into the active optical fiber 32, the signal is transmitted and received in the network. If a failure occurs in the active optical fibers 31 and 32 or the active signal processing module 3 and normal operation in the active system becomes impossible,
The optical switching module 2 isolates the faulty part, and the standby system signal processing module 4 and the standby system optical fibers 33, 3
Normal operation as a network is secured by switching to 4. In the normal duplex ring network, the signal direction of the working fiber and the signal direction of the standby fiber are connected so as to be opposite to each other.

FIG. 3 is a block diagram showing an example of the optical switching module 2 and the signal processing modules 3 and 4 in the communication node device 1 of FIG. 2, in which the active and standby signal processing modules 3 and 4 are optical. / Electricity (O / E) converter 2
1, 24, electric / optical (E / O) converters 22 and 25, and transmission / reception circuits 23 and 26. In addition, the optical switching module 2 includes three 2 × 2 optical switch elements 1
It is composed of 5, 16 and 17. The 2 × 2 optical switching element has its transmission path switched to a bar state or a cross state by a control signal, and in the bar state, the light from the optical fibers A and B is respectively fed to the optical fibers A ′ and B ′, as shown in FIG.
In the cross state, the light from the optical fibers A and B is transmitted to the optical fibers B ′ and A ′, respectively, as shown in FIG.

The operation of the optical switching module shown in FIG. 3 will be described below.

First, the received signal from the working optical fiber 31 is dropped into the working O / E converter 21, and the transmission signal from the working E / O converter 22 is dropped into the working optical fiber 32. As for the state, as shown in FIG. 6, the 2 × 2 optical switch elements 15 and 16 are switched to the bar state, and the 2 × 2 optical switch element 17 is switched to the cross state. In this case, the received signal from the spare optical fiber 33 is the spare O / E converter 2
4 and the transmission signal from the standby system E / O converter 25 is inserted into the standby system optical fiber 34.

Next, the received signal from the active optical fiber 31 is branched to the active O / E converter 21, and the transmitted signal from the active E / O converter 22 is inserted into the standby optical fiber 34 and folded back. As shown in FIG. 7, the insertion folded state is 2 × 2.
All the optical switch elements 15, 16 and 17 are switched to the bar state. In this case, the received signal from the spare optical fiber 32 is branched to the spare O / E converter 24, and the spare E
The transmission signal from the O / O converter 25 is inserted into the working fiber 32 and folded back.

Further, as shown in FIG. 8, the passing state in which the received signal from the working optical fiber 31 is passed as it is, the 2 × 2 optical switching elements 15 and 16 are set in the cross state,
The 2 × 2 optical switch element 17 is switched to the bar state. As a result, the received signal from the working optical fiber 31 is not dropped into the signal processing module 3 but is passed through as it is to the working optical fiber 32, and the standby optical fiber 3
The received signal from 3 also passes through as it is and is transmitted to the working optical fiber 32, and the received signal from the standby optical fiber 33 also passes through as it is and is transmitted to the standby optical fiber 34.

Further, as shown in FIG. 9, all the 2 × 2 optical switch elements 15, 16 and 17 are in the pass-back state where the received signal from the working optical fiber 31 is passed as it is and is returned to the standby optical fiber 34. To the cross state. As a result, the received signal from the working optical fiber 31 passes through the signal processing module 3 without being dropped and is passed back to the standby optical fiber 34, and the received signal from the standby optical fiber 33 also passes through the working system optical fiber 34 as it is. It is returned to the optical fiber 32.

FIG. 10 to FIG. 13 show a duplex ring network configuration by a communication node device using the above-mentioned conventional optical switching module. Four communication node devices 1a, 1b, 1c, 1d are used as a working optical fiber. Three
1, 32 and standby optical fibers 33, 34 are interconnected in a ring shape. Hereinafter, each network configuration will be described. 10 to 13, the number of communication node devices forming the ring network is four, but other numbers may be used.

FIG. 10 shows a network configuration during normal operation. In each communication node device 1a, 1b, 1c, 1d, the optical switching modules 2a, 2b, 2c, 2d are placed in the add / drop state shown in FIG. As a result, the active signal processing modules 3a, 3b, 3c, 3d can be used to transmit and receive signals between the communication node devices through the optical fibers 31, 32. In this case, the signal direction in the network is clockwise.

11 and 12 show the communication node device 1a.
The active signal processing module 3a inside has failed (X in the figure)
(Indicated by a mark), the network configuration is shown in FIG. 11 when the operation of the network is switched from the active system to the standby system. Similarly, the signal processing module 4 of the standby system is still in the branch insertion state shown in FIG.
Signals can be transmitted and received between the communication node devices by the optical fibers 33 and 34 using a, 4b, 4c, and 4d. In this case, the signal direction in the network is counterclockwise. On the other hand, FIG. 12 shows a configuration in the case where the communication node device 1a is in the passing state.
Then, by bringing the optical switching module 2a into the passing state shown in FIG. 8, the communication node devices 1b, 1c, 1
The signal processing modules 3b, 3c, and 3d of the active system can be used between d, and signals can be transmitted and received between the communication node devices by the optical fibers 33 and 34.

FIG. 13 shows a fault in the active signal processing module 3a of the communication node device 1a and the transmission line between the communication node device 1a and the communication node device 1b (indicated by a mark X in the figure).
Occurs, and a loopback network is configured by the communication node device 1a and the communication node device 1b,
In the communication node device 1a, the optical switching module 2a
To the pass-back state shown in FIG. 9, and the communication node device 1
In b, the optical switching module 2b is put into the add / drop back-folding state shown in FIG. 7, and by using the optical fiber of the active system and the standby system and the signal processing module, the signal transmission between the communication node devices 1b, 1c and 1d Can send and receive.

[0013]

However, in the optical switching module having the above-mentioned configuration, the signal processing module is provided in the communication node device in two sets each of the active system and the standby system. The received signal from the fiber can be input only to the signal processing module of the active system, and the received signal from the optical fiber of the backup system can be input only to the signal processing module of the backup system. Therefore, when the signal processing module of the active system fails, the operation is switched from the active system to the standby system over the entire network as shown in FIG.
As shown in 2, in the communication node device in which the active signal processing module has failed, the signal must be passed through without being dropped into the signal processing module. When switching the operation of the network from the active system to the standby system, control for system switching of the entire network, adjustment of switching timing between each communication node device, system re-establishment control after switching to the standby system, etc. There is a problem that the control related to the switching becomes complicated and the time required for the switching becomes long. In addition, when passing through a failed communication node device, complicated switching control such as system switching over the entire network is not necessary, but in the communication node device where the active signal processing module has failed, normal standby system signals can be used. Despite the presence of the processing module, there is a problem in that signals cannot be transmitted and received, and in the transmission line that sandwiches the failed communication node device, the transmission distance becomes twice that in normal operation and the transmission signal quality deteriorates. Further, when a failure occurs in the transmission line adjacent to the active signal processing module, the signal must pass through the communication node device where the active signal processing module has failed, as shown in FIG. However, despite the presence of a normal standby signal processing module, there is a problem in that signals cannot be transmitted and received, and the transmission line distance becomes twice as long as in normal operation, degrading the transmission signal quality.

The object of the present invention is to solve the above problems, and even if the signal processing module of the active system fails, the signal processing module of the standby system is used to provide continuous and stable communication. It is to provide an optical switching module capable of

[0015]

According to the present invention, in order to achieve the above object, a transmission line by an optical fiber and a transmission / reception signal processing module provided in a communication node device are respectively a working signal processing module and a standby signal processing module. The optical switching module in the communication device of the redundant ring network is composed of an input optical transmission line connected to one of the input ends and the standby signal processing module connected to the other end, and an output end of the third 2 × 2 described later. A second 2 × 2 optical switch for connecting the working signal processing module to the other of the optical switch, and a spare optical transmission line to one of the input ends and the working signal processing module to the other end of the output end A second 2 × 2 optical switch that connects a third 2 × 2 optical switch described later to one side and the standby system signal processing module to the other side, and the first 2 × 2 optical switch to one of the input ends. From the second 2 × 2 optical switch, which connects the second optical switch to the other to the second optical switch, and connects the working optical transmission line to one of the output ends and the standby optical transmission line to the other In this communication node device, between the working optical transmission line and the first 2 × 2 optical switch, and between the standby optical transmission line and the second 2 × 2 optical switch,
The working optical transmission line is connected to one of the input ends, and the standby optical transmission line is connected to the other end, and the first 2 × 2 optical switch is connected to one of the output ends and the second 2 × 2 optical switch is connected to the other end. And a fourth 2 × 2 optical switch for connecting the above is arranged.

[0016]

According to the present invention, the received signal from the optical fiber of the active system is branched to the O / E converter of the active system, and the E / E of the active system is supplied.
When the transmission signal from the O converter is inserted into the optical fiber of the working system, the first, second and third 2 × 2 optical switch elements are placed in the bar state, and the fourth 2 × 2 optical switch element is placed. Switch to the cross state respectively. The received signal from the optical fiber of the working system is branched to the O / E converter of the protection system,
When the transmission signal from the O-converter is inserted into the working system by the optical fiber, the first 2 × 2 optical switch element is set to the cross state, and the second, third and fourth 2 × 2 optical switch elements are set. Switch to each bar state. The received signal from the working optical fiber is branched to the working O / E converter, and the working system E / E converter is
When the transmission signal from the O converter is inserted into the optical fiber of the standby system and folded back, all 2 × 2 optical switch elements are switched to the bar state. In the case where the received signal from the optical fiber of the working system is branched to the O / E converter of the backup system and the transmission signal from the E / O converter of the backup system is inserted into the optical fiber of the backup system and folded back, The first and fourth 2 × 2 optical switching elements are switched to the cross state, and the second and third 2 × 2 optical switching elements are switched to the bar state.

By the way, the optical switching module can branch the received signal from the optical fiber of the active system to either the O / E converter of the active system or the standby system, and further, the E / O conversion of the active system or the standby system. Since the transmission signal from the device can also be inserted into the working optical fiber, it is not necessary to switch over the entire ring network as in the conventional system even if the working or standby signal processing module fails, and the failed communication node The number of transmission lines that sandwich the device will not be twice that of normal operation.

[0018]

1 is a block diagram showing an embodiment of the present invention, in which 1 is a communication node device, 2 is an optical switching module, and a first 2 × 2 optical switching element 11 and a second 2 × 2 optical switching element 11 are provided.
Two-optical switch element 12 and third 2 × 2 optical switch element 13
And a fourth 2 × 2 optical switch element 14, that is, four 2 × 2 optical switch elements. Reference numeral 3 is a signal processing module for the active system, which is composed of an O / E converter 21, an E / O converter 22, and a transmission / reception circuit 23, and 4 is a signal processing module for the standby system.
O / E converter 24, E / O converter 25, and transmission / reception circuit 26
Consists of. Furthermore, 31 and 32 are optical fibers of the current system,
Reference numerals 33 and 34 are optical fibers of the standby system. In addition, the first to fourth 2 × 2 optical switch elements 11, 12, 1
As described above, 3 and 14 are switched to the bar state shown in FIG. 4 or the cross state shown in FIG.

Next, the operation of the optical switching module of this embodiment will be described with reference to FIGS. 1 and 14 to 19.
FIGS. 14 to 19 are state diagrams of the optical switching module 2 shown in FIG. 1, respectively. The branching / insertion state from the working optical fiber to the working signal processing module and the branching from the working optical fiber to the standby signal processing module are respectively shown. The case where the optical fiber is in the add / drop state, the pass state, the pass return state, and the return optical path from the active optical fiber to the standby signal processing module is shown. First, as shown in FIG. 14, the add / drop state from the active optical fiber to the active signal processing module is the first to the third 2 × 2 optical switch element 1
1, 12, and 13 are switched to the bar state, and the fourth 2 × 2 optical switch element 14 is switched to the cross state. As a result, the received signal from the working optical fiber 31 is transmitted to the working O / E converter 21 via the first and second 2 × 2 optical switching elements 11 and 12, and the working E / O is transmitted. The transmission signal from the converter 22 is the third and fourth 2 × 2 optical switch elements 13 and 14
Is transmitted to the working optical fiber 32 via the. Similarly, the received signal from the standby optical fiber 33 is O of the standby system.
The transmission signal from the standby E / O converter 25 is transmitted to the / E converter 24 and is transmitted to the standby optical fiber 34. The O / E converters 21 and 24 detect the received optical received signal and output the electric received signal to the signal processing circuit, and the E / O converters 22 and 25 receive the electric received signal from the signal processing circuit. The optical transmission signal is modulated by the transmission signal and output.

Next, in the add / drop state from the spare optical fiber to the spare signal processing module shown in FIG. 15, the first 2 × 2 optical switch element 11 is in the crossed state, and the second, third and fourth optical fibers are in the cross state. The 2 × 2 optical switch elements 12, 13 and 14 are switched to the bar state. As a result, the received signal from the working optical fiber 31 is transmitted to the first and third 2 × 2 optical switch elements 11,
13 is transmitted to the O / E converter 24 of the standby system via the transmission line 13, and the transmission signal from the E / O converter 25 of the standby system is currently used via the second and fourth 2 × 2 optical switch elements 12 and 14. It is transmitted to the system optical fiber 32. Similarly, the reception signal from the standby optical fiber 33 is transmitted to the active O / E converter 21, and the transmission signal from the active E / O converter 22 is transmitted to the standby optical fiber 34. The E / O converters 22 and 25
The operations of the O / E converters 21 and 24 are the same as those in FIG.

Next, in the passing state shown in FIG. 16, both the first and fourth 2 × 2 optical switch elements 11 and 14 are in the bar state or the cross state, and the second and third 2 × 2 optical switch elements 11 and 14 are in the bar state or the cross state.
The two optical switch elements 12 and 13 are switched to the cross state. As a result, the received signal from the working optical fiber 31 is transmitted to the first, second and fourth 2 × 2 optical switch elements 11, 1
2, 14 or the working optical fiber 32 through the first, third, and fourth 2 × 2 optical switch elements 11, 13, and 14.
Be transmitted to. Similarly, the received signal from the standby optical fiber 33 is transmitted to the standby optical fiber 34.

Next, in the case of the passing back-folding state shown in FIG. 17, the first 2 × 2 optical switch element 11 is placed in either the bar state or the cross state, and the fourth 2 × 2 optical switch element 14 is placed. Either the cross state or the bar state opposite to that of the first 2 × 2 optical switching element 11, the second and third 2
The × 2 optical switch elements 12 and 13 are switched to the cross state. As a result, the received signal from the working optical fiber 31 is transmitted to the first, second and fourth 2 × 2 optical switch elements 11, 1
It is transmitted to the standby optical fiber 34 via the second and the fourth or the first, the third and the fourth 2 × 2 optical switch elements 11, 13 and 14. Similarly, the received signal from the standby optical fiber 33 is transmitted to the active optical fiber 32.

Next, the branching from the working optical fiber to the working O / E converter 21 shown in FIG. 18 and the insertion and return state from the working O / E converter 22 to the standby optical fiber are as follows:
To the fourth 2 × 2 optical switch elements 11, 12, 13, 1
Switch all 4 to bar state. As a result, the received signal from the active optical fiber 31 passes through the first and second 2 × 2 optical switch elements 11 and 12 and the active O / E converter 2
1 and the transmission signal from the active E / O converter 22 is transmitted to the standby optical fiber 34 via the third and fourth 2 × 2 optical switch elements 13 and 14. Similarly, the received signal from the standby optical fiber 33 also receives the backup O / E converter 24.
And the transmission signal from the standby E / O converter 25 is transmitted to the working optical fiber 32. The operations of the E / O converters 22 and 25 and the O / E converters 21 and 24 are the same as in FIG.

Next, the branching from the working optical fiber to the spare O / E converter 24 and the insertion back from the spare E / O converter 25 to the working optical fiber shown in FIG.
And the fourth 2 × 2 optical switch elements 11 and 14 are switched to the cross state, and the third and fourth 2 × 2 optical switch elements 12 and 13 are switched to the bar state. As a result, the received signal from the active optical fiber 31 is transmitted to the standby O / E converter 24 via the first and third 2 × 2 optical switching elements 11 and 13, and the standby E / O converter is transmitted. The transmission signal from 25 is transmitted to the standby optical fiber 34 via the second and fourth 2 × 2 optical switch elements 12 and 14. Similarly, the received signal from the standby optical fiber 33 is transferred to the active O / E converter 21,
The transmission signal from the active E / O converter 22 is transmitted to the active optical fiber 32. The E / O converters 22 and 25
The operations of the O / E converters 21 and 24 are the same as those in FIG.

Next, a description will be given of a dual ring network configuration composed of communication node devices using the optical switching module according to the present invention. FIG. 20 is a diagram showing a network configuration when the active signal processing module 3a fails in the communication node device 1a using the optical switching module 2a according to the present invention. In the communication node device 1a, the optical switching module 2a is shown in FIG. From the working optical fiber shown in FIG.
By switching to the add / drop state, the other communication node devices 1b, 1c, 1d are not affected at all, and the transmission line between the communication nodes has the same length as that during normal operation, and a failure occurs. The same signal transmission and reception as before can be stably performed in the network. In addition, in FIG. 21, the active signal processing module 1a of the communication node device 1a has failed, and the communication node device 1a and the communication node device 1b have a failure.
FIG. 20 is a diagram showing a network configuration in the case where a failure has occurred in a transmission line between the optical switching modules 2a in the communication node device 1a from the working optical fiber shown in FIG. 19 to the standby signal processing module 4a. In the communication node device 1b, all communication node devices 1a, 1b, 1c, and 1d are switched to the return insertion state in which the standby optical fiber 33 shown in FIG. 18 is added to the standby signal processing module 4b. Signals can be sent and received.

Further, when the optical switching module according to the present invention is used, the operation of the entire network can be switched from the active system to the standby system due to the failure of the active signal processing module, and the failed communication node device can pass the signal. It can be performed in the same manner as the conventional optical switching module. 20 and 21, the ring network comprises four communication node devices,
It is obvious that the same network configuration can be taken with other numbers.

[0027]

As described above, according to the present invention, 4
An optical switching module composed of two 2 × 2 optical switching elements, capable of branching a received signal from the active optical fiber or the standby optical fiber to either the active signal processing module or the standby signal processing module, and Since the transmission signal from either the active system signal processing module or the standby system signal processing module can be inserted into the active system optical fiber or the standby system optical fiber, even if either the active system or the standby system signal processing module fails By switching with the optical switching module, there is no effect on the entire ring network, the transmission line length between the communication node devices does not double, and the normal operation before a failure occurs The same stable communication can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical switching module according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a communication node device

FIG. 3 is a block diagram of a conventional optical switching module.

FIG. 4 is a state diagram of a 2 × 2 optical switch element in a bar state.

FIG. 5 is a state diagram of a 2 × 2 optical switch element in a cross state.

FIG. 6 is a state diagram of a conventional optical switching module in a drop / insert state.

FIG. 7 is a state diagram of a conventional optical switching module in a state where the add / drop is folded back.

FIG. 8 is a state diagram of a conventional optical switching module in a passing state.

FIG. 9 is a state diagram of a conventional optical switching module in a pass-back state.

FIG. 10 is a configuration diagram of a dual ring network by a communication node device using a conventional optical switching module.

FIG. 11 is a configuration diagram of a dual ring network by a communication node device using a conventional optical switching module.

FIG. 12 is a configuration diagram of a dual ring network by a communication node device using a conventional optical switching module.

FIG. 13 is a configuration diagram of a dual ring network by a communication node device using a conventional optical switching module.

FIG. 14 is a state diagram of an optical switching module according to the present invention in a state of add / drop by a working optical fiber and a working signal processing module.

FIG. 15 is a state diagram of an optical switching module according to the present invention in a state of add / drop by a working optical fiber and a standby signal processing module.

FIG. 16 is a state diagram of the optical switching module according to the present invention in a passing state.

FIG. 17 is a state diagram of the optical switching module according to the present invention in a passing-back state.

FIG. 18 is a state diagram of the optical switching module according to the present invention in a state where the working optical fiber is branched to the working signal processing module and is inserted and folded back to the protection optical fiber.

FIG. 19 is a state diagram of the optical switching module according to the present invention in a state where the optical fiber of the current system is branched to the signal processing module of the standby system and is inserted into the optical fiber of the standby system and folded back.

FIG. 20 is a configuration diagram of a dual ring network by a communication node device using an optical switching module according to the present invention.

FIG. 21 is a configuration diagram of a dual ring network by a communication node device using an optical switching module according to the present invention.

[Explanation of symbols]

1 ... Communication node device, 2 ... Optical switching module,
3 ... Working system signal processing module, 4 ... Standby system signal processing module, 11-17 ... 2 × 2 optical switch element, 21,
24 ... O / E converter, 22, 25 ... E / O converter, 2
3, 26 ... Transmitting / receiving circuit, 31, 32 ... Working optical fiber, 33, 34 ... Standby optical fiber.

Claims (1)

[Claims] 1. An optical switching module in a communication device of a duplex ring network, wherein a transmission / reception signal processing module provided in an optical fiber transmission line and a communication node device comprises an active system signal processing module and a standby system signal processing module, respectively. , An active optical transmission line is connected to one of the input ends, and the standby system signal processing module is connected to the other end, and one of the output ends is provided with a third 2
A first 2 × 2 optical switch that connects the × 2 optical switch to the other of the active signal processing module, and a standby optical transmission line to one of the input ends and the active signal processing module to the other to output One of the two ends of the third
A second 2 × 2 optical switch for connecting the standby system signal processing module to the other × 2 optical switch, and the first 2 × 2 optical switch for one of the input terminals and the second 2 × 2 optical switch for the other. A communication node device comprising a third 2 × 2 optical switch connected to an optical switch and having a working optical transmission line connected to one of the output ends and a standby optical transmission line connected to the other end of the working optical transmission line. Between the first 2 × 2 optical switch and between the standby optical transmission line and the second 2 × 2 optical switch, one of the input ends has the working optical transmission line and the other has the standby system. An optical transmission line is connected, and a fourth 2 × 2 optical switch for connecting the first 2 × 2 optical switch to one of the output ends and the second 2 × 2 optical switch to the other end is arranged. Optical switching module.