JP2003101484A - Optical branching and multiplexing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical branching/multiplexing equipment with which the number of input/output ports is reduced and a switch is simplified. SOLUTION: A plurality of optical branching/multiplexers (Add/Drop Multiplexer: ADM) are connected by active and reserve ring optical transmission lines and used for an optical transmission network for performing transmission with an optical signal. In the equipment, an optical matrix switch for branching a liquid between the optical transmission line 10 and a tributary in order to control the destination of the optical signal is divided into two, i.e., a ring side switch 200 for switching the signal at the transmission speed of active and reverse optical transmission line side hierarchy and a tributary side switch 300 for switching the signal at the transmission speed of a tributary side hierarchy then, independent configuration is adopted at the ring side by wavelengths λ1-λn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of optical ADM devices, which are connected by service (current) and protection (spare) optical transmission lines to connect terminal devices accommodated in the optical ADM device. The present invention relates to an optical branching / multiplexing device of an optical transmission network system that transmits an optical signal having a unique wavelength.

[0002]

2. Description of the Related Art With the widespread use of high-speed Internet and broadband multimedia services, there is an urgent need to increase the capacity of transmission lines of information and communication networks and improve their economic efficiency. Among them, optical fiber communication technology is one of the important network construction technologies.

In an optical fiber transmission system, Time Division Multiplexing (TDM: Time Division Multiplexing) has been used so far to increase the speed of a signal transmitted in one optical fiber on a time axis.
(ltiplexing) method to increase capacity.

Further, a wavelength division multiplexing (WDM) is used for multiplexing optical signals of a plurality of different wavelengths in one optical fiber, and amplifying and relaying the optical signals in a batch of multiple wavelengths.
The iplexing) method is also being studied, and the dramatic increase in transmission capacity and long-distance transmission have become reality.

In addition, in a transmission system using such a WDM transmission system, in order to avoid an increase in the hardware scale proportional to the number of wavelengths to be multiplexed, it is necessary to perform Add / Drop in units of wavelengths that are wavelength-multiplexed. Optical AD as a basic unit
Application of an M (Add / Drop Multiplexer) device is under consideration.

A conventional optical transmission device used in a wavelength multiplexing ring network using the optical ADM technology will be described. The conventional technique described here as an example is a so-called FFRN (Four Fiber Ring) in which a ring network is configured by a transmission line fiber of an active system and a transmission line fiber of a standby system.
An optical transmission device in a network configuration. The concept of this type of device is described, for example, in the following references. Rainer Iraschko et.al “An Optical
4-Fiber bi-directional Line-switchedRing ”, OFC'9
9, TuK3-1, 1999. In an optical transmission device, an optical signal that has been wavelength-multiplexed and transmitted through a transmission line fiber is an optical wavelength demultiplexing function unit (WDM-) that is one of the components of the optical transmission device.
R) is input to each wavelength λ1, λ2, ...
It is once separated for each λn. The optical signals of wavelengths λ1, λ2, ..., λn separated by the WDM-R are input to an optical matrix functional unit such as an optical cross connect.

The optical matrix functional unit takes out optical signals of preset wavelengths λi, λj, and λk of specific channels to the low-order group side (Drop), and passes optical signals of other wavelengths (Through). Output to the adjacent station. In addition, the optical matrix functional unit has a dropped wavelength λ.
Add your own signal to the i, λj, and λk channels (Ad
d) and output as an optical signal for transmission to the adjacent station. And
This optical signal to be transmitted to the adjacent station is wavelength-multiplexed by the optical wavelength multiplexing function unit (WDM-T) on the transmitting side and is sent out via the output side transmission line fiber.

By the way, when a plurality of optical ADM devices are connected to the network by a service line (SRV (working system) transmission line) and a protection line (PRT (standby system) transmission line), the network line connection is made. When a system is constructed in which a ring connection is made and a line is protected by switching to a protection line when a failure occurs in the service line between the ADM devices, normally the service line (SRV) ) System, and if a line failure occurs in that system, regarding the section where the line failure occurs,
By forming a detour using a protection line (PRT) so as not to hinder the transmission, the transmission is continued.

In this four-fiber ring network, in the optical ADM device for performing ring protection, the service line on the ring side (optical transmission line side) for two systems, clockwise / counterclockwise, and the protection line are provided. In order to accommodate two clockwise / counterclockwise systems, it is necessary to provide a total of four ports for connection.

Further, the optical ADM device is an Add / Drop device.
4 lines (tributary side line)
It will be a device with ports.

[0011]

Therefore, the optical switch unit for switching signals between the input and output ports requires a matrix configuration of the number of input ports × the number of output ports, and the optical switch unit must be provided at each intersection of the matrix. 8 (the number of input ports) × 8 (the number of output ports) = 64 optical branching devices S for switching the passage route of are also required. Furthermore, when the device scale is increased by optical wavelength multiplexing,
Since the number of inputs and outputs is n times the wavelength multiplexing number n, 8
n (number of input ports) × 8n (number of output ports) = 64n ²
An optical SW unit having a large circuit scale, which has a number of optical branching devices S, is required. Therefore, the scale of the device becomes large and the device becomes expensive.

Therefore, the object of the present invention is to
The number of I / O ports can be reduced and the SW section can be simplified.
Therefore, it is an object of the present invention to provide an optical branching / multiplexing device capable of reducing the cost of the device.

[0013]

In order to achieve the above object, the present invention is configured as follows. That is, a plurality of optical branching / multiplexing devices (optical ADM devices) for service (active)
And a protection (spare) ring type optical transmission line are connected to each other, and an optical branching and multiplexing device of an optical transmission network that transmits optical signals of unique wavelengths between terminal devices accommodated in an optical ADM device. In order to control the destination of the signal, an optical matrix switch that performs optical branching between the optical transmission line side and the tributary side is a ring for switching the signal at the transmission speed of the working and standby optical transmission line side layers. 2 for the side and for the tributary side that switches signals at the transmission speed of the tributary side layer 2
It is characterized in that it is divided and the ring side is configured independently for each wavelength.

Further, in the optical matrix switch for the optical transmission line side hierarchy, the ring side is used for the input and output ports for the number of the installed optical transmission lines for the current and the spare, the input port for Add and the port for Drop. The present invention is characterized in that it has a matrix structure of the number of input ports × the number of output ports, each of which has an active port and a spare port.

In the optical branching / multiplexing device of the present invention, an optical matrix switch for performing optical branching is provided on the ring side and the tributary side layer for switching the layers on the working and protection optical transmission line sides. The tributary side for switching is divided into two, and the ring side has an independent structure for each wavelength.

Therefore, the optical matrix switch has a small number of input / output port configurations per layer, and the number of optical branching devices for switching the optical signal path of the optical matrix switch can be reduced.

For a four fiber ring configuration, n × n =
Since the switch of n ² has 4 sides and bidirectional input / output,
Two optical matrix switches are required for each, and the number of optical branching devices is n ² × 4 × 2 = 8n ² .

This number is significantly smaller than the conventional one. Therefore, according to the present invention, it is possible to provide an optical branching / multiplexing device that can reduce the device configuration and thus reduce the cost.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A characteristic configuration of the present invention is that the configuration of an optical matrix switch section (line switching section) of an optical branching / multiplexing apparatus (optical ADM apparatus) is the same as that of ring side (high speed side) signals.
HS-SW (high speed switch) unit for performing dd / Drop and LS-SW (low speed switch) for performing switching on the tributary side (low speed side) line
There is a point that the system is divided into two parts, and such a configuration simplifies the configuration of the optical matrix switch, and the details will be described below.

An example of an optical ADM network system to which the technique of the present invention is applied will be described.

<System Configuration> FIG. 1 is a diagram showing an example of an optical ADM network to which the present invention is applied. This optical ADM network includes a plurality of nodes (optical transmission devices) 1 to 4 using an optical ADM device and an active optical transmission line 10-.
1, 10-2 and standby optical transmission lines 10-3 and 10-4. These active optical transmission lines and standby optical transmission lines 10-1
10-4 are used to connect the nodes 1 to 4 in a ring shape.

Further, in the figure, Tributary 1 and Tributary 2 each indicate the tributary side, which means that it is a downstream layer connected to the outside of the network.

In each of the nodes 1 to 4 using the optical ADM device as the optical transmission device, the connection relationship between the optical signal on the optical fiber transmission line and the signal on the tributary side is set in advance so that the working optical transmission line is It has a function of performing circuit switching between the optical transmission lines 10-1, 10-2, the standby optical transmission lines 10-3, 10-4 and the transmission line on the tribitary side.

In FIG. 1, the tributary side signal is shown to be input / output by each node for two channels, but in the present invention, the number of channels of the tributary side signal input / output to each node is two channels. It is not limited to.

In the following, for convenience, one of the transmission lines connected to the node is WEST and the other is EA.
Indicated as ST (east).

Here, the character SRV is used for the active system, that is, the service system, and P for the standby system, that is, the protection system.
Displayed with the letters RT.

The working transmission line on the WEST side is connected to West S
ervice (West Service; West SRV), protection transmission line for West Protection (West Protection; West PRT), and EAST side current transmission line
East Service (East SR)
V) and the protection transmission line are described as East Protection (East PRT). Also,
In the network as shown in FIG. 1, an information transmission path between a tributary side of a node and a tributary side of another node is described as a communication path, and information transmitted via this communication path is described as traffic. .

(First embodiment) <Node configuration to which the present invention is applied> Next, each node 1 to 4
The configuration will be described.

FIG. 2 is a block diagram showing a configuration example of each of the nodes 1 to 4 in the first embodiment to which the present invention is applied.

As shown in FIG. 2, each of the nodes 1 to 4 is constructed by using the optical ADM device 100 according to the present invention.
In the optical ADM apparatus 100 to which the present invention is applied, a wavelength demultiplexing unit DWDM that demultiplexes a plurality of optical wavelengths and an optical signal of that wavelength for each wavelength is added / dropped / through.
(Through) It consists of the line switching unit to be connected. The line switching unit serves as a line switch (HS-S) for performing Add / Drop and Through of the high-speed side signal.
W (high speed switch) section 200 and a tributary switch (LS-S) for switching to a low speed side line
The W (low speed switch) section 300 is divided into two types.

Then, a tributary switch (LS-S
The W) section 300 is provided with a wavelength converter 310 for converting the wavelength of the input optical signal. The wavelength converter 310 is a wavelength of the optical signal separated from the line switch (HS-SW) unit 200 (any one of wavelengths λ1 to λn).
Is converted into a wavelength used in the transmission line on the tributary side and is taken in, and the wavelength of the optical signal input from the tributary side is converted to a required specific wavelength (any one of wavelengths λ1 to λn) and the line switch ( HS-SW) unit 200
Hand over to.

The wavelength demultiplexing unit DWDM is "EAST S".
RV system "," EAST PRT system "," WEST S
There are "RV system" and "West PRT system".

The line switch section 200 is a line switch (HS-SW) 200 provided for each wavelength to be multiplexed.
Each of these line switches (HS-SW) 200-1 to 200-n is composed of an optical switch. The optical switch is a switch for switching an optical signal propagation path that has a plurality of input ports and a plurality of output ports and guides light from a desired input port to a desired output port.

These line switches (HS-SW) 2
The optical switches used as 00-1 to 200-n are
As shown in FIG. 3, it is composed of an 8 × 8 optical matrix switch having 8 input ports and 8 output ports. For the input ports, four input ports on the line side ("EAST SRV system", "EAST PRT system," WEST SRV system "," WEST PRT system ") and four tributary side inputs Port ("EA
"For Add connection to ST SRV system", "EASTPRT
Add to system, Add to WEST SRV system
"For connection", "For Add connection to the West PRT system")
There are a total of eight optical waveguides Wg.

For the output ports, four output ports ("EAST") connected to the line on the tributary side are provided.
For Drop connection from SRV system "," EAST PR "
Drop connection from T system, "Drop connection from West SRV system", "Dr from West PRT system"
op connection ") and four output ports on the line side (" E
"AST SRV system", "EAST PRT system", "W
Eight optical waveguides Wg are provided to guide "for EST SRV system" and "for WEST PRT system").

An optical branching device S for switching the propagation direction of light to each intersection of the 8 × 8 optical waveguide matrix.
Is arranged.

By controlling the optical branching device S at each intersection, the optical switch can branch the light input from the input port to switch the propagation destination and guide it to the target output port.

Next, the structure of the tributary switch section 300 will be described. Line switch (HS-SW) unit 200
Similarly to the above, the tributary switch unit 300 also includes a plurality of tributary switches (LS-SW) 300-1 to 300-n.
Composed of. Then, each tributary switch (L
Each of the S-SWs) 300-1 to 300-n also has a plurality of input ports and output ports, and is configured by an optical switch that guides light from a desired input port to a desired output port. Where each tributary switch is
Corresponding to wavelengths λ1 to λn, it is necessary to prepare for SRV system / PRT Add connection, Dorp connection, and for each “EAST”, “WEST”, etc. , 300-wavelength system-branch number format. For example, 300-1-1,3
00-1-3, 300-3-2, 30
It is assumed that 0-1-1 is a notation indicating that the central 1 is for λ1.

Tributary switch (LS-SW) 30
The optical switches constituting the 0-1 to 300-n are, as shown in FIG. 4, HS-SW 200-provided for each wavelength.
1 to 200-n input ports (n types of "input 1" to "input n") and output ports ("output 1" to "output n")
(N kinds of)).

In this system, the switch (LS-SW) of this n × n configuration is used for the SRV system for each wavelength λ1 to λn.
dd connection, PRT system Add connection, SRV system Do
Eight sets are used for rp connection, for PRT system Dorp connection, and for each "EAST" and "WEST".

And regarding the four for Add connection,
The n-port on the input side is connected to each tributary line, and the n-port on the output side is connected to the line switches 200-1 to 200-n provided for each wavelength.

Regarding the four drop connections,
Conversely, the input side has line switches 200-1 to 200-n
Then, the output side is connected to each tributary side line.

In the case of a tributary switch (LS-SW), the n × n configuration does not require the “Add” connection signal to be “Drop” connection, and the “Drop” connection.
This is because the signal to be connected is not “Add” connected.

This tributary switch (LS-SW)
In the optical switch of FIG. 4 which comprises the above-mentioned structure, there are n optical waveguides Wg connecting n input ports, and there are n optical waveguides Wg intersecting these and connecting n output ports in n rows and n columns. The optical branching device S for switching the propagation direction of the light is arranged at each intersection of the optical waveguide matrix of the above, and by controlling the optical branching device S at each intersection, the propagation destination of the light input from the input port is controlled. Is a switch for switching an optical signal propagation path, which is branched to a desired output port.

Next, the operation of the present apparatus having such a configuration will be described.

The n-wavelength multiplexed optical signal transmitted by the service fiber 10-2 enters the DWDM of the WEST SRV, where each wavelength, that is, λ1 to λ.
It is input to the corresponding one of the line switches (HS-SW) 200-1 to 200-n in the line switch (HS-SW) unit 200 which is separated into n and is provided for each wavelength.

Line switch (HS-SW) 200-
In Nos. 1 to 200-n, the input optical signal is subjected to the through connection or the Drop connection according to the preset state of the communication path.

Here, the line switches (HS-SW) 200-1 to 200-n having the configuration shown in FIG. 4 are, for example, "input 1" to "input 8" among eight input ports, for example, "input 1". "Input 1" for input of "WEST SRV system", "Input 2" for "input of EAST SRV system"
"Input 3" is assigned to the input for the "WEST PRT system", "Input 4" is assigned to the input for the "EAST PRT system", and "Input 5" is assigned to the "WEST SRV from the tributary side". "Input 6" for input of "for system"
Is for “input for EAST SRV system” from the tributary side, and “input 7” is for “WEST from the tributary side”
For input for "PRT system", "input 8" is assigned for input for "EAST PRT system" from the tributary side. Further, among eight output ports "output 1" to "output 8" For example, set “output 1” to “WEST SRV
"For system" output, "Output 2" for "EAST SRV system output", and "Output 3" for "WEST PRT system"
"Output 4" is assigned to the output for "EAST PRT system", and "output 5" is used for the output of "WEST SRV system" to the tributary side.
"Output 6" is for "East SRV system output" to the tributary side, and "Output 7" is for "W" to the tributary side.
It is assumed that "output 8" has been allocated for output for "EST PRT system" and for output for "EASPRT system" to the tributary side.

In this case, the optical signal transmitted by being multiplexed from the ring side is separated by the DWDM for each wavelength from λ1 to λn, and then the optical signal for each wavelength is converted to the line switch (HS-SW) 200-. Line switch (HS-SW) 20 corresponding to each wavelength of 1 to 200-n
0-1 and 200-n will be input.

In this example, since the optical signal which is optically multiplexed from the ring side and transmitted is from EASTSRV, the line switches (HS-SW) 200-1 ,.
In 200-n, an optical signal is received via the "input 2" port which is "input for EAST SRV system".

Then, this input optical signal is controlled among the "output 1" to "output 8" by the control of the internal switch element S in the line switches (HS-SW) 200-1, 200-n. Corresponding to the required output ports "output 1" to "output 8".

On the other hand, if it is an optical signal from the tributary side, among the input ports "input 1" to "input 8", "input 5" for input of "WEST SRV system", respectively.
The optical signal will be input to the port.

The input optical signal is sent to the line switch (HS-SW) 20 of the line switch (HS-SW) unit.
In 0-1, to 200-n, by controlling the internal switching element S, among the "output 1" to "output 8", the required output ports "output 1" to "output 8" corresponding to the control are output. Is output.

For example, in the case of this example, since the inputted optical signal is inputted to the "input 5", the internal switches in the line switches (HS-SW) 200-1 to 200-n. It is led to "output 1" by the control of the element S, and "WEST SR" is output from the port of the "output 1".
It becomes the output for "V system" and is given to the "WEST SRV system" DWDM.
M is multiplexed with optical signals of other wavelengths and transmitted to the WEST side of the fiber 10-1 which is the transmission line for the SRV system,
It will be transmitted to the next node.

As described above, the ring side port separated by the DWDM is connected to Through, or to the low speed side by Drop connection, and the port from the low speed side is Ad-connected.
It is possible to make a d-connection or switch the line when a failure occurs.

Line switch (HS-SW) 200-
The optical signal output from 1 to 200-n for the tributary side is output for the "EAST SRV system", and therefore is output from "output 6". This signal is output by the wavelength converter 310. After converting the wavelength to λ0 (where λ0 is an easy-to-handle arbitrary wavelength), the "East SRV system" of the tributary switch (LS-SW) 300-1-1 to 300-n-8 for low speed is used. It is given to the tributary switch (LS-SW) assigned for Drop, and can be sent to the tributary side through a desired output port. On the tributary side, any channel can receive an optical signal with a wavelength of λ0.

On the other hand, an optical signal input from the tributary side (this optical signal may be λ0 in any channel)
Is a tributary switch (LS-SW) 300-1-
"WEST SRV system" of 1 to 300-n-8
Is input to an input port of a tributary switch (LS-SW) assigned for Add of, and an incoming call destination of the line switch (HS-SW) unit 200 is input via the tributary switch (LS-SW). "WE in the line switch (HS-SW) of the wavelength corresponding to
The signal is input to the input port assigned for Add of "ST SRV system". At this time, the optical signal of the wavelength λ0 is converted by the wavelength converter 310 into an optical signal of the required wavelength among λ1 to λn. After the conversion, it is output to the line switch (HS-SW) unit 200.

Then, this input optical signal is sent to the line switch (HS-S) of the line switch (HS-SW) unit 200.
W) In the outputs 200-1, 200-n, by controlling the internal switch element S, among "output 1"-"output 8",
Required output port “output 1” according to the control
~ Is output to "output 8".

For example, in the case of this example, since the input optical signal is for the "WEST SRV system" Add, it is input to the input port "input 5", and the line switch (HS-SW) 200- In 1 to 200-n, it is guided to "output 1" by the control of the internal switching element S, and becomes the "west SRV system" output from the "output 1" port "west SRV system". DW
Will be given to DM. And this DWDM1
At 11, the signal is multiplexed with optical signals of other wavelengths, transmitted to the WEST side of the fiber 10-1 which is the transmission line for the SRV system, and then transmitted to the next node.

As described above, the ring side port separated by the DWDM is connected by Through or Drop connection to the low speed side, and the port from the low speed side is set to Ad.
It becomes possible to make a d-connection or switch the line when a failure occurs.

Next, the line switch (HS-SW) unit and the tributary switch (LS-S) having the above-mentioned configuration are provided.
The simplification scale of the system by adopting the element configuration of the section W) will be described.

The above line switch (HS-SW) 2
Since 00-1 to 200-n are SW units for each wavelength of λ1 to λn, the line switch (HS-SW) unit 200 is configured by n switch units.
Therefore, the line switch (HS-
In the (SW) unit 200, the required circuit scale is “64 × n” SW element configurations.

On the other hand, the line switch (HS-SW) unit 2
00 to tributary switch (LS-SW) unit 300
Signals input / output to / from each port are bi-directional for each wavelength type (4 ports for WEST SRV, EAST SRV, WEST
There is a total of 4) for PRT and EAST PRT.

Since the number of wavelength types, that is, the number of wavelength division multiplexing is n, the tributary switch (LS-SW) is used.
The number of input / output signals of the unit is the number of “(4 × n) ports”.

The line switch (HS-SW) unit can switch to any of these four ports for each wavelength λ, and the line switch (HS-S) of the same wavelength can be used.
It is not necessary for the tributary switch (LS-SW) unit to switch the Add / Drop signal from the W) unit.

Since it is not necessary to perform switching for the Add side signal and the Drop side signal, the tributary switch (LS-SW) unit is provided for each port of λ1 to λn in the line switch (HS-SW) unit. One SW, that is, "port of wavelength λ1 to wavelength λn
SW input by 1 ”,“ port of wavelength λ1 to wavelength λn
SW for outputting to 1 ”,“ port of wavelength λ1 to wavelength λn
Input / output to an arbitrary port becomes possible by using the SW of 2 input SW ”...

Therefore, in the system of the present invention, when the number of wavelength multiplexing is n, the SW configuration has four ports of tributary switch (LS-SW) having n inputs × n outputs × (1 + for input +
For output 1) = 4 x 2 = 8 pieces will be prepared,
n-input x n-output tributary switch (LS-SW)
If 8 units are prepared, the required switching process for 1 wavelength can be performed.

In this case, the tributary switch (LS-
The size of the number of SW element components in the (SW) section is
eight ⁿ × n = n ² pieces of switch units, i.e.,
The total number of constituent elements is 8n ² per wavelength.

As a result, in the system of the present invention, the total number of constituent elements including the line switch (HS-SW) section and the tributary switch (LS-SW) section can be 64n + 8n ² per wavelength. On the other hand, in the case of a system that is not divided into two, a line switch (HS-SW) unit and a tributary switch (LS-SW) unit, the service line 2 is used in the 4-fiber ring system.
Input and output (total 8) for each line and two protection lines, and each Add / Drop (2 lines for service line and 2 lines for protection line)
The number of input / output ports is 8n because it is necessary to add n for the wavelength division multiplexing of a total of 8 for dd and for Drop.
× 8n = 64n ² and the circuit scale is 64 per wavelength.
Since it is n ² , compared with this, 64n + 8n ² <64n ² . That is, when expressed as a ratio, the “method of the present invention”:
"The method that does not divide the line switch (HS-SW) unit and the tributary switch (LS-SW) unit into two" is 1
Since 64n + 8n ² : 64n ² = 8 + n: 8n per wavelength, the difference is obvious. From this, it can be seen that the circuit scale is significantly reduced when the system of the present invention is adopted as the number of wavelength division multiplexes increases. Therefore, according to the present invention, the device configuration can be reduced, and accordingly, an inexpensive device can be provided. Moreover, the fact that the scale can be reduced greatly contributes to reliability and power consumption.

(Second Embodiment) In the first embodiment, the wavelength conversion unit 310 is provided between the line switch (HS-SW) unit 200 and the tribitary-side switch 300. When the optical signal of the same wavelength is used in the transmission line of the above and the transmission line of the tribitary side, the wavelength conversion unit 31
A configuration in which 0 is omitted is also possible. An example will be described below.

FIG. 5 shows another example of the configuration of the optical ADM apparatus (optical branch multiplexer) 100 of the present invention. The second shown here
The optical ADM apparatus 100 according to the embodiment of
"TSRV system", "EAST PRT system", "WEST
"Add / Drop / Through connection of optical signals of each wavelength to the wavelength demultiplexing units (DWDM) 111 to 114 for" SRV system "and" WEST PRT system "and the wavelength demultiplexing units 111 to 114 are connected. And a line switch unit 200 for sending the optical signal Drop-connected by the line switch unit 200 to the tributary side and for sending the optical signal from the tributary side to the line switch unit 200 for Add connection. In this embodiment, the wavelength of the optical signal handled by the line switch unit and the low speed unit (tributary side) is λ1.
.About..lamda.n, the wavelength converter 310 is not provided.

The line switch section 200 is a line switch (HS-SW) 200 provided for each wavelength to be multiplexed.
-1, to 200-n, which are optical switches. The optical switch has a plurality of input ports and a plurality of output ports, and is a switch for switching an optical signal propagation path that guides light from a desired input port to a desired output port. The line switch (HS) in the second embodiment is used. -SW) 200-1, to 200-n,
This is as described in FIG.

The tributary switch section 300 in this embodiment is also composed of tributary switches (LS-SW) 300-1 to 300-8 for each wavelength λ1 to λn.

Similar to the first embodiment, each tributary switch is used for SRV system / wavelengths λ1 to λn.
For PRT, for each Add connection, for Dorp connection, and for each "EAST", "WEST"
However, the notation is simplified in FIG. 5.

Then, each tributary switch (LS-
SW) 300-1 to 300-8 also have a plurality of input ports and a plurality of output ports, respectively, and are each configured by an optical switch as described in FIG. 4 for guiding light from a desired input port to a desired output port. There is.

In the present system having such a configuration, assuming that the setting condition and the assumption condition are the same as those in the first embodiment, the n-wavelength multiplexing transmitted through the service fiber 10-2 is performed. The generated optical signal is WEST S
Enter the RV DWDM 113, where the wavelengths (λ1
Line switches (HS-SW) 200-1, to 20 in the line switch (HS-SW) unit 200 that are separated and provided for each wavelength.
It is input to the corresponding one of 0-n.

Line switch (HS-SW) 200-
In Nos. 1 to 200-n, the input optical signal is through-connected or Drop-connected as necessary.

That is, the optical signal transmitted from the ring side by optical multiplexing is separated by wavelength in the DWDM unit 113, and then the optical signal by wavelength is converted into a line switch (HS-S).
W) 200-1, ~ 200-n, line switches (HS-SW) 200-1, ~ corresponding to the respective wavelengths.
200-n will be input.

Line switch (HS-SW) 200-
The optical signals output from 1 to 200-n for the tributary side are "EAST SRV system" in the above setting.
Since it is for the output of the output, it will be output from "output 6", and this signal is as it is, the tributary switch (L
S-SW) 300-1, to 300-8 of "EAS
It is given to a tributary switch (LS-SW) assigned for Drop of "T SRV system", and can be sent to the tributary side through a desired output port.

On the other hand, the optical signal input from the tributary side is the tributary switch (LS-SW) 300-1,
~ 300-8 Add of "WEST SRV system"
Tributary switch (L
S-SW) is input to the input port, and a line switch (HS) is supplied through this tributary switch (LS-SW).
-SW) "WEST S" in the line switch (HS-SW) of the wavelength corresponding to the called party of the destination 200
It is input to the input port assigned for Add of "RV system".

The input optical signal is sent to the line switch (HS-S) of the line switch (HS-SW) unit 200.
W) In the outputs 200-1, 200-n, by controlling the internal switch element S, among "output 1"-"output 8",
Required output port “output 1” according to the control
~ Is output to "output 8".

In the case of the example assumed here, since the input optical signal is for the "WEST SRV system" Add, it is input to the input port "input 5", and the line switch (HS-SW) In the case of "WE 1", it is guided to "output 1" by the control of the internal switch element S, and the "WESTER SRV system" is used as the output for "WES SRV system"
It is given to the DWDM 111 for ST SRV system. Then, the fiber 1 which is the transmission line for the SRV system is multiplexed with the optical signal of another wavelength by this DWDM 111.
It is transmitted to the west side of 0-1 and is transmitted to the next node.

By the way, also in the second embodiment, the line switches (HS-SW) 200-1 to 200-200 are provided.
Since −n is a SW unit for each wavelength of λ1 to λn, the line switch (HS-SW) unit 200 is configured by n switch units according to n types of wavelengths to be handled. Therefore, the circuit scale required in the line switch (HS-SW) unit 200 in the system of the present invention is “64 × n” SW element configurations per wavelength.

On the other hand, the line switch (HS-SW) unit 2
00 to tributary switch (LS-SW) unit 300
The signals input to and output from are bidirectional for each wavelength type of n types.
Port (for WEST SRV, for EAST SRV, W
There is a total of 4) for EST PRT and EAST PRT.

Since the number of wavelength types, that is, the number of wavelength division multiplexing is n, the tributary switch (LS-SW) is used.
The number of input / output signals of the unit is the number of “(4 × n) ports”.

The line switch (HS-SW) unit can switch to any of these four ports for each wavelength λ, and the line switch (HS-S) of the same wavelength can be used.
It is not necessary to switch the Add / Drop signal from the W) section in the tributary switch (LS-SW) section, and it is not necessary to switch the Add side signal and the Drop side signal. The switch (LS-SW) unit can input / output to / from an arbitrary port by using one optical switch for each port of λ1 to λn in the line switch (HS-SW) unit.

Therefore, as in the first embodiment, the total number of constituent elements including the line switch (HS-SW) section and the tributary switch (LS-SW) section is 64n + 8n ² circuits per wavelength. On the other hand, in the case of a system in which the line switch (HS-SW) unit and the tributary switch (LS-SW) unit are not divided into two, in the 4-fiber ring system, as described above, per wavelength Since 8n × 8n = 64n ² is obtained, also in the case of this embodiment, it is possible to obtain the effect that the device configuration can be reduced and the device can be made inexpensive by that amount, as in the first embodiment.

The present invention is not limited to the examples shown in the above embodiments, but can be modified in various ways. For example, in the above-described embodiment, the case where the bidirectional pairs are connected by a total of four optical fibers is shown.
The present invention is not limited to this, and can be applied to a system in which two fibers are connected.

Further, FIG. 1 shows a ring network in which nodes are connected in a ring shape.
It is not necessarily limited to the ring form, for example,
It is also applicable to a linear system in which some of the nodes in FIG. 1 are not connected.

In the present invention, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the section of the problem to be solved by the invention is
When one of them can be solved and at least one of the effects described in the section of the effect of the invention can be obtained, a structure in which this constituent element is deleted can be extracted as the invention.

[0091]

As described above, according to the present invention, a plurality of optical ADM devices are provided for service (current use) and protection (standby).
In the optical transmission network that connects with the optical transmission line of No. 2 and transmits the optical signals of the specific wavelengths between the terminal devices accommodated in the optical ADM device, the device configuration of the switch part for switching the transmission destination of the optical signal is provided. Therefore, it is possible to provide an optical branching / multiplexing device that can be made small and thus cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of an optical transmission system to which the present invention is applied.

FIG. 2 is a diagram for explaining a configuration example of a node in the optical transmission system as the first exemplary embodiment of the present invention.

FIG. 3 is a diagram for explaining a conceptual configuration of an optical matrix switch for a line switch (HS-SW).

FIG. 4 is a diagram for explaining a conceptual configuration of an optical matrix switch for a tributary switch (LS-SW).

FIG. 5 is a block diagram showing a configuration example of an optical ADM device (optical branching / multiplexing device) 100 according to a second embodiment of the present invention.

[Explanation of symbols]

1-4 Nodes 10 ... Ring-shaped optical transmission lines (service and protection fibers) 10-1, 10-2 ... Service line fibers 10-3, 10-4 ... Protection line fiber 100 ... Optical ADM device (optical branching / multiplexing device) 111, to 114 ... DWDM unit 200 ... Line switch (HS-SW) unit 200-1, to 200-n ... Line switch (HS-S)
W) 300 ... Tributary switch (LS-SW) unit 300-1, 300-8, 300-1-1, 300
-1-8, ~ 300-n-1, ~ 300-n-8 ... Tributary switch (LS-SW) 310 ... Wavelength converter Wg ... Optical waveguide S ... Optical brancher

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Claims (2)

[Claims] 1. An optical branching / multiplexing device used in an optical transmission network for connecting a plurality of optical branching / multiplexing devices by working and standby ring type optical transmission lines to transmit an optical signal, wherein the optical transmission line side and the tributary side are provided. An optical matrix switch for branching optical signals between the ring side and the tributary side layer for switching signals at the transmission speed of the working and protection optical transmission line side layers. The optical branching / multiplexing device is characterized in that it is divided into two for the tributary side, and the line side is configured independently for each wavelength. 2. An optical matrix for the optical transmission line side layer.
The switch has the input and output ports for the ring side for the number of installed optical transmission lines for the working and protection, the input port for Add and the output port for Drop, respectively, and the number of input ports × An optical branching / multiplexing device having a matrix configuration of the number of output ports.