JP2000115133A - Optical path cross connection device and optical network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with the acceleration and volume enlargement of information by demultiplexing wavelength multiplex optical signals inputted from respective inter-input-station optical transmission lines to the optical signals of respective wavelengths, dividing the optical signals inputted from an optical transmission line into the two optical signals, respectively converting them to the optical signals of desired wavelengths, outputting active signals and protection signals and selecting and outputting either one of the optical signals. SOLUTION: An optical divider 22 divides the optical signals inputted from an intra-input-station optical transmission line into two and a wavelength converter 24 outputs the two divided optical signals to the input port of an optical switch 30. An optical demultiplexer 20 demultiplexes WDM signal light to the optical signals of the respective wavelengths and outputs them to the input port of the optical switch 30. The optical switch 30 outputs the active signals and the protection signals outputted from the wavelength converter 24 to a first output port, and an optical multiplexer 26 multiplexes the plural optical signals of the different wavelengths outputted from the first output port and outputs them to the optical transmission line. An optical selector 28 selects one of them and outputs it to the optical transmission line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical path cross-connect device and an optical network.

[0002]

2. Description of the Related Art With the increase in speed and capacity of information, there is a demand for broadband and large capacity networks and transmission systems. As one means for realizing this, construction of an optical network based on WDM technology is desired. And
An optical path cross-connect device (optical XC) is a core device for constructing an optical network.

FIG. 16 is a diagram showing a configuration example of an optical network. The optical XC2 shown in this figure accommodates a plurality of input / output optical transmission lines 8 and 10, and routes an optical signal wavelength-multiplexed from an input optical transmission line to a desired output optical transmission line for each wavelength. It is. In the case of long-distance transmission, an optical amplifier 12 is inserted between the inter-station links of the optical XC 2 and connected to another communication device (for example, an electric cross-connect (electric XC)) via the intra-station optical transmission line 10. You. These devices are controlled by the operation system 6.

FIG. 17 is a diagram showing a network configuration example of an optical network using a plurality of optical XCs. As shown in this figure, the optical network includes a plurality of optical XC2 # i (i = 1 to
6), and each optical XC2 # i is connected to each other via a plurality of optical XCs and optical transmission lines 8.

[0005] On the other hand, as the transmission capacity increases, transmission path failure has a great effect. Therefore, it is necessary to switch information that has been disconnected due to a failure to a normal transmission path to recover from the failure. Generally, there are two restoration methods, restoration and protection.

The former is a method of searching for a free band on the network at the time of a failure and circumventing the failed information (working path). The latter is to secure a backup path for the working path. In this method, the same information as that of the active path is transmitted on the network. Comparing the two methods simply, the latter method requires more bandwidth for the backup path than the former method, but allows high-speed switching.

[0007] The optical XC system comprises an optical XC that accommodates a transmitting end.
A method in which the node C uses one wavelength for one optical path to the node accommodating the receiving end and does not convert the wavelength in the node (fixed wavelength type); (Wavelength conversion type).

FIG. 18 is a configuration diagram of a fixed wavelength light XC. As shown in the figure, the wavelength division multiplexed optical signal input from the inter-station transmission line 8 is converted into each wavelength λ _i (i
= 1 to n) and are input to the input port of the optical switch unit 16. The optical switch unit 16 outputs the optical signal of the wavelength λ _i input to the input port from the output port corresponding to the optical path.

When the optical signal of the wavelength λ _i output from the output port is relayed to another node, it is multiplexed by the optical multiplexer 18 and transmitted through the inter-station transmission line 8. If the own node is the receiving end, the electric XC
Is transmitted to The optical signal input from the intra-station optical transmission line 10 is converted into an optical signal of a predetermined wavelength by the wavelength converter 20 and transmitted to the inter-station optical transmission line 8 through the optical switch 16 and the multiplexer 18. You. Here, the output wavelength tunable wavelength converter 20 is provided on the input side of the fixed wavelength intra-office link because the newly set path wavelength is the path state (the use state of the wavelength) in the entire network at that time. It is because.

FIG. 19 is a configuration diagram of a wavelength conversion type light XC. The wavelength conversion type optical XC is the same as the fixed wavelength type optical XC up to the point where a wavelength multiplexed optical signal is input from the inter-station optical transmission line 8 and routing is performed by the optical switch unit 16, The optical signal output to the transmission line 8 is converted into a wavelength corresponding to the optical path by the wavelength converter 22,
The difference is that the signal is output to the optical multiplexer 18. The optical signal input from the intra-station optical transmission line 10 is output from the optical switch unit 16 instead of being input to the optical switch unit 16 after being wavelength-converted by the wavelength converter 20 as in the fixed wavelength type. The difference is that the wavelength of the optical signal is converted by the wavelength converter 22.

FIG. 20 is a diagram showing a conventional transmission line protection system (prior art 1). As shown in this figure, in the prior art 1, in each XC2 # i (i = 1 to 6), both the working transmission line W and the protection transmission line P are laid in pairs. For example, the optical signal input from the intra-station transmission line of XC2 # 1 is distributed by the distributor 24 into a working signal and a protection signal.
, And the protection signal is transmitted by the protection transmission line P. When a failure occurs in the working transmission line W, the selector 26 of the XC2 # 2 on the receiving side switches to a protection signal from the protection transmission line P.

FIG. 21 is a diagram showing a conventional transmission line protection method (prior art 2). As shown in this figure, in the prior art 2, with respect to the route of the working transmission line W,
This is a method of making the route of the protection transmission line P different from the route of the active transmission line W (another node). In this example, the protection transmission line P is set to XC2 # 1-XC2 # 6 for the current transmission line W between XC2 # 1 and XC2 # 2.
XC # 5-XC # 2.

FIG. 22 is a diagram showing conventional transmission line protection (prior art 3). As shown in this figure,
In the prior art 3, a protection signal is inserted into a vacant band (vacant time slot) and transmitted via an XC on a route different from the route of the working signal. In this example, with respect to the working signal A _W between XC2 # 1-XC2 # 2, via the XC2 # 6-XC2 # 5, are transmitted by inserting the protection signal A _P time slot T3. Further, with respect to the working signal B _W between XC2 # 1-XC2 # 2- XC2 # 3, XC2 # 6-XC2 # 5-XC
Via 2 # 4, the protection signal _BP is inserted into the time slot T4 and transmitted.

[0014]

However, the conventional optical XC has the following problems. In the prior art 1, when the working transmission line W and the protection transmission line P are laid in the same earthen pipe, it becomes an obstacle at the same time. However, there is a problem in that the construction cost is high to lay different earth pipes with different routes (not through other XCs).

In the prior art 2, it is necessary to prepare more spare optical transmission paths than in the prior art 1. At present, there is a problem that optical transmission lines are becoming inadequate due to high speed and large capacity of information, and there is a problem that even if a new cable is to be laid, the cost is expensive and the cable cannot be easily laid.

The unit of processing (unit of path) has become larger with the increase in the speed and capacity of information, and wavelength division rather than time division in an optical network based on WDM. There is a problem that it cannot be applied to WDM.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and is intended to provide an optical XC and an optical network based on WDM that can respond to an increase in the speed and capacity of information and can be constructed at low cost. It is intended to provide an optical XC and an optical network that can be used.

[0018]

FIG. 1 is a diagram illustrating the principle of the present invention. According to the present invention, an optical demultiplexer 20 that separates a wavelength multiplexed optical signal input from each input station optical transmission line into optical signals of each wavelength, and an optical signal input from each input station internal optical transmission line by 2 An optical splitter 22 for splitting two optical signals, and an optical splitter 2
2 converts the two optical signals distributed from the optical signal into optical signals of desired wavelengths, and outputs a working signal and a protection signal. A wavelength converter 24 multiplexes a plurality of optical signals having different wavelengths and outputs a signal. Optical multiplexer 26 for outputting to an optical transmission line
, A working signal and a protection signal are input, an optical selector 28 for selecting one of the optical signals and outputting the selected optical signal to the optical transmission line in the output station, a plurality of input ports, and a plurality of optical selectors optically connected to the optical multiplexer. A first output port and a plurality of second output ports optically connected to the optical selector; a working signal output from the wavelength converter is input from one of the input ports to correspond to a first optical path of the working signal; Output to one of the first output ports optically connected to an optical multiplexer for outputting an optical signal to an optical transmission line between output stations, and input a protection signal output from the wavelength converter from one of the input ports. , The protection signal is output to one of the first output ports optically connected to an optical multiplexer that outputs an optical signal to an optical path between output stations corresponding to a second optical path of the protection signal, and is output from the optical demultiplexer. Optical signal input from one of the input ports And a first output port or a second output optically connected to an optical multiplexer or an optical selector for outputting an optical signal to an inter-output-station optical transmission path or an output-station optical transmission path corresponding to a third optical path of the optical signal. An optical switch 30 for outputting to one of the ports.

According to the above configuration, the first optical path and the second optical path of the working signal and the protection signal of the optical signal input from the optical transmission line in the input station are set. The optical distributor 22 distributes an optical signal input from the input intra-station optical transmission line into two optical signals. The wavelength converter 24 converts one of the two divided optical signals into an optical signal having a wavelength assigned to the first optical path, and the other optical signal is assigned to the second optical path. The signal is converted into an optical signal having a wavelength and output to an input port of the optical switch 30.

The optical demultiplexer 20 separates the WDM signal light transmitted through the optical transmission line between input stations into optical signals of respective wavelengths,
Output to the input port of the optical switch 30. Optical switch 3
0 is the wavelength converter 24 according to the first optical path of the working signal.
Is output to the first output port, and the wavelength converter 2 outputs the working signal according to the second optical path of the protection signal.
4 outputs the protection signal output to the first output port.

The optical switch 30 converts the optical signal output from the optical demultiplexer 20 according to a third optical path of the optical signal.
Output to the first output port or the second output port. The optical multiplexer 26 multiplexes a plurality of optical signals having different wavelengths output from the first output port and outputs the multiplexed optical signals to an output optical path between stations. The optical selector 28 selects either the working signal or the protection signal output from the second output port, and outputs the selected signal to the optical transmission line in the output station.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 2 is a configuration diagram of the light XC according to the first embodiment of the present invention. The optical XC according to the present embodiment can be applied to both the fixed wavelength type and the wavelength conversion type, but shows the case of the fixed wavelength type. In the case of the wavelength conversion type, FIG.
In FIG. 19, the wavelength converter 52 is eliminated, and
The wavelength converter may be provided on the output side of the optical switch as described above.

As shown in FIG. 1, the optical XC accommodates a plurality of inter-station optical transmission lines 8 and a plurality of intra-station optical transmission lines 10, and includes a working / protection signal routing unit 50, a plurality of optical distributors 56 and A plurality of optical selectors 58 are provided. Light X
The C system includes the optical XC, the controller 60, and the operation system 62.

The working / protection signal routing unit 50 includes an optical demultiplexer 14, a wavelength converter 52, and an optical switch 5.
4 and an optical multiplexer 18. The inter-station optical transmission line 8 transmits optical signals of a plurality of wavelength multiplexed wavelengths λ _i (i = 1 to n). The optical demultiplexer 14 is provided for each input inter-station optical transmission line 8 and separates the WDM signal light input from the inter-station optical transmission line 8 into signal light of each wavelength λ _i (i = 1 to n). Thus, the signal light of each wavelength is output to the input port of the optical switch 54.

The wavelength converter 52 converts the output signal light of the optical distributor 56 into a desired wavelength under the control of the controller 60 and outputs the converted signal light to the optical switch 54. FIG.
FIG. 3 is a diagram illustrating an example of a wavelength converter in FIG. 2. As shown in this figure, the wavelength converter 52 includes an opto-electric converter 60 that converts an optical signal into an electric signal, and an electro-optical converter 62 that converts the electric signal into an optical signal having a desired wavelength.

The electro-optical converter 62 has a semiconductor laser and an optical modulator, and outputs light of a desired wavelength according to a control signal from the controller 60 input to the semiconductor laser. The output light from the semiconductor laser is modulated by the optical modulator according to the output electric signal.

The optical switch 54 converts the signal light input to the input port into the inter-station optical transmission line 8 or the intra-station optical transmission line 10 under the control of the controller 60.
To the optical multiplexer 18 or the optical selector 58 for optical output.

FIG. 4 shows an example (4 ×) of the optical switch shown in FIG.
It is a figure which shows 4). The optical switch shown in FIG.
It consists of four switch elements S _ij (i, j = 0 to 3) and an optical waveguide. Each switch element S _ij is a switch that connects the input port #i and the output port #j. Normally, all switch elements S _ij are set to “cross”. Then, switching is realized by setting a predetermined switch element S _ij to a “bar” according to the input / output connection pattern. In this example, the input port # 0 is switched to the output port # 1 by changing the switch element _S01 from "cross" to "bar". The controller 60 controls the “cross” or “bar” of the switch element S _ij in accordance with an instruction from the operation system 62.

The optical multiplexer 18 is an optical inter-station optical transmission line 8 for output.
It is provided for each optical signal and multiplexes optical signals of a plurality of wavelengths λ _i (i = 1 to m, m ≦ n) output from the optical switch 54 and outputs the multiplexed optical signal to the inter-station optical transmission line 8. Optical selector 58
Is to select one of the working signal and the protection signal in accordance with the selection signal from the controller 60, and to output the selected signal to the intra-office optical transmission line 10.

The controller 60 has the following functions. In accordance with an instruction from the operation system 62, the wavelength converter 52 is controlled so as to convert the current signal output from the optical distributor 56 into an optical signal having a wavelength assigned to the protection signal.

In accordance with an instruction from the operation system 62, the optical switch 54 is controlled to output an optical signal to an output port corresponding to the optical path of the optical signal input to each input port. For example, when the optical switch 54 shown in FIG. 4, when outputting the optical signal input port #i to the output port #j, a control voltage is applied so that the switch element S _ij to "bar" to the switch element S _ij .

A selection signal for selecting either the working signal or the protection signal is supplied to the optical selector 58.
Output to The controller 60 is provided with an optical selector 58.
When a failure occurs in the working signal in accordance with a monitoring signal of a monitoring circuit (not shown) for monitoring the working signal and the protection signal (not shown), the optical selector 58 outputs a selection signal so as to select the protection signal.

The operation system 62 is, for example, a workstation provided for each optical XC, and has the following functions. For the optical signal output from the intra-station optical transmission line 10 of the own node, an optical path (wavelength and route) of another route of the working signal and the protection signal is secured and set from the own node to the node at the receiving end. The setting of the optical path is, for example,
This is performed by registering the currently set optical path and optical network configuration in a database.

The controller 60 is notified of the wavelengths assigned to the optical paths of the set working signal and protection signal and the input port #i and output port #j of the optical switch 54 corresponding to the optical path. Input port #i and output port #j
Is, for example, the configuration of the wavelength converter 52 connected to the input intra-station optical transmission line 10 and the optical multiplexer 18 connected to the output inter-station optical transmission line 8 corresponding to the wavelength of the optical path and the optical path. decide.

An optical path is notified via a LAN or the like to an operation system 62 that manages another optical XC that is a path of an optical path of the set working signal and protection signal.

When an optical path is notified from another operation system 62, the relationship between the input port #i and the output port #j of the optical switch 54 to which the working signal or the protection signal is input is determined according to the notified optical path. Notify the controller 60.

The operation of the light XC shown in FIG. 2 will be described below. (A) Transmission at Transmission Node Prior to transmission of an optical signal from the intra-station optical transmission line 10, the operation system 62 sets the optical path of the working signal of the optical signal and the optical path of the protection signal by different routes. The controller 60 notifies the controller 60 of the wavelength of the optical path of the working signal and the protection signal, and notifies the input port #i and the output port #j of the optical switch 54. Further, the optical path is notified to the optical XC operation system which is the route of the set optical path. The controller 60 controls the switch elements of the wavelength converter 52 and the optical switch 54 according to the notification from the operation system 62.

The optical distributor 56 distributes the optical signal input from the intra-office optical transmission line 10 into a working signal and a protection signal, and outputs the signal to the wavelength converter 52. Wavelength converter 52
Converts the signal into a working signal or a protection signal of a desired wavelength under the control of the controller 60 and outputs the signal to the input port of the optical switch 54. The optical switch 54 outputs the working signal and the protection signal to a desired output port corresponding to the optical path under the control of the controller 60.

The working signal and the protection signal output to the output port are input to the optical multiplexer 18. The optical multiplexer 18 multiplexes a plurality of input optical signals having different wavelengths and outputs the multiplexed optical signals to the inter-station optical transmission line 8. The working signal and the protection signal output to the inter-station optical transmission line 8 are received by the optical XC corresponding to the optical path.

(B) Transmission at the relay node When the optical XC is a relay node for a working signal or a protection signal, the operation system for managing the optical XC transmits the optical XC from the operation system 62 for the optical XC at the transmitting end. Information on the optical path (wavelength and optical XC of the partner to be transmitted / received) is received and notified to the controller 60. The controller 60 connects the input port and the output port of the optical switch 54 according to the optical path. The optical switch 54 outputs the input optical signal to an output port. Thus, the working signal and the protection signal are relayed by the optical XC of the relay node.

(C) Reception at the terminal node When the optical XC is the terminal node of the working signal and the protection signal, the optical XC operation system transmits the signal from the transmission end optical XC operation system 62 to the optical path of the signal. Information (wavelength, optical XC at the receiving end, and electrical XC at the receiving end), and notifies the controller 60 of the received information.

The controller 60 connects the input port of the optical switch 54 and the output port connected to the optical selector 58 according to the optical path. The optical switch 54 outputs the input optical signal to an output port. Since the working signal and the protection signal are transmitted to the terminal node according to each optical path, they are input to the corresponding optical selector 58.
Although not shown, the monitoring circuit constantly monitors the optical level and the like of the optical signal and checks whether the working signal and the protection signal are normal. If the working signal is found to be faulty, the monitoring circuit notifies the controller 60 accordingly.

When the controller 60 receives a notification from the monitoring circuit that the working signal is faulty, it outputs a selection signal to the optical selector 58 so as to select a protection signal. The optical selector 58 selects a working signal or a protection signal according to the selection signal, and transmits the selected signal to the intra-office optical transmission line 10. The optical signal transmitted to the intra-office optical transmission line 10 is received by the electric XC.

As described above, according to the first embodiment, a protection path can be set between the transmission and reception lights XC for each working path, and there is no need to prepare a spare optical transmission path. In the event of a transmission path failure, it is only necessary to switch over using the optical selector of the receiving node, and high-speed failure recovery is possible.

FIG. 5 is a diagram showing an optical network using the optical XC of FIG. As shown in FIG.
An optical network is configured by C68 # i (i = 1 to 6). Between the optical XCs 68 # 1 and 68 # 2, the optical XC6
8 # 1 and 68 # 6, between light XC68 # 2 and 68 # 3, between light XC68 # 2 and 68 # 5, between light XC68 # 6 and 68 # 5, and light XC68 # 4 and 68 #. Light XC for 5
An inter-station optical transmission line 8 is provided between 68 # 4 and 68 # 3. Note that the controller 60 and the operation system 62 in FIG. 2 are omitted.

The operation of the optical network shown in FIG. 5 will be described below. (A) Setting of Optical Path In this example, the optical XC 68 # 1 is the transmitting end of the optical signals A and B, the optical XC 68 # 2 is the receiving end of the optical signal A, and the optical XC 68 #
3 is a receiving end of the optical signal B. Optical signal A, the working signal A _W of B, B _W, carried out by the protection signal A _P, the operating system 62 to set the light path B _P. At this time, the operating system 62 allocates the output wavelength of each optical signal to a wavelength at which a path can be secured end-to-end according to the state of the network.

In this example, the optical path of the working signal A _W has a wavelength of λ ₁ and a route of optical XC68 # 1-optical XC # 68 #.
2, the optical path of the protection signal A _P has a wavelength lambda _3,
The route is optical XC68 # 1-optical XC68 # 6-optical XC68
# 5-light XC68 # 2. The optical path of the working signal B _W has a wavelength of λ ₂ and a route of optical XC68 # 1-optical XC # 6.
The optical path of 8 # 2-optical XC68 # 3 and the protection signal _BP has a wavelength of λ ₄ and a route of optical XC68 # 1-optical XC.
68 # 6-Light XC68 # 5-Light XC68 # 4-Light XC6
8 # 3.

(B) Operation of Light XC68 # 1 FIG. 6 is an explanatory diagram of the operation of light XC1 in FIG. The optical signals A and B transmitted from the intra-office optical transmission line 10 are distributed by the optical distributor 56 # 1 into a working signal and a protection signal. The distributed optical signal is used as a working / protection signal routing unit (abbreviated as a routing unit) 50.
Using the # 1 wavelength converter, according to the optical path, the working signal λ
₁ (A _W ), λ ₂ (B _W ), protection signal λ
₃ (A _P ) and λ ₄ (B _P ).

The working signals λ ₁ (A _W ) and λ ₂ (B _W ) are provided by the optical switch and the optical multiplexer of the routing unit 50 # 1.
Is output to the inter-station optical transmission line 8 to which the optical XC 68 # 2 is connected. Protection signal λ ₃ (A _P ), λ
₄ (B _P ) is the inter-station optical transmission line 8 to which the optical XC 68 # 6 is connected.
Is output to

(C) Operation of Light XC68 # 2 FIG. 7 is an explanatory diagram of the operation of light XC2 in FIG. Hikari XC
Working signal λ ₁ (A _W ), λ output from 68 # 1
₂ (B _W ) is transmitted through the inter-station optical transmission line 8 to the optical XC 68 #
2 is input. Further, the protection signal λ ₃ (A _P ) output from the optical XC 68 # 1, as described later,
The optical XC 68 # 6 -optical XC 68 # 5 is input to the optical XC 68 # 2 via the inter-station optical transmission line 8.

The routing section 50 # 2 of the optical XC68 # 2
Is separated into each wavelength by an optical demultiplexer, and the working signal λ ₁ (A
_W ) and the protection signal λ ₃ (A _P )
8 # 2, and the working signal λ ₂ (B _W ) is converted to an optical XC68 #
3 is output to the inter-station optical transmission line 8 to which it is connected. The optical selector 58 # 2 outputs the working signal λ ₁ (A _W ) according to the selection signal.
Alternatively, the protection signal λ ₃ (A _P ) is selected and output to the intra-office optical transmission line 10.

(D) Operation of Light XC68 # 3 FIG. 8 is an explanatory diagram of the operation of the light XC3 in FIG. Hikari XC
The working signal λ ₂ (B _W ) output from 68 # 2 is input to the optical XC 68 # 3 via the inter-station optical transmission line 8. Further, the protection signal λ ₄ (B _P ) output from the optical XC 68 # 1 is transmitted through the optical XC 68 # 6-optical XC 68 # 5-optical XC 68 # 4 and the inter-station optical transmission line 8 as described later. It is input to the optical XC 68 # 3.

The routing section 50 # 3 of the optical XC68 # 3
Is separated into each wavelength by an optical demultiplexer, and the working signal λ
₂ (B _W ) and the protection signal λ ₄ (B _P ) to the optical selector 58 # 3. The optical selector 58 # 3 selects the working signal λ ₂ (B _W ) or the protection signal λ ₄ (B _P ) according to the selection signal, and outputs the selected signal to the intra-office optical transmission line 10.

(E) Operation of Optical XC 68 # 5 FIG. 9 is an explanatory diagram of the operation of the optical XC 5 in FIG. Hikari XC
Protection signal λ output from 68 # 1
₃ (A _P ) and λ ₄ (B _P ) are input to the optical XC 68 # 6 via the inter-station optical transmission line 8. Hikari XC68 # 6 is
The protection signals λ ₃ (A _P ) and λ ₄ (B _P ) are input and output to the optical XC 68 # 5 via the inter-station optical transmission line 8. The optical XC68 # 5 receives the protection signal λ ₃ (A
_P ) is output to the inter-station optical transmission line 8 to which the optical XC 68 # 2 is connected, and the protection signal λ ₄ (B _P ) is output to the optical XC 68 #.
The signal is output to the inter-station optical transmission line 8 to which the signal 4 is connected.

(F) Operation of Optical XC 68 # 4 The λ ₄ (B _P ) output from the optical XC 68 # 5 is input to the optical XC 68 # 4 via the inter-station optical transmission line 8. Light X
The C68 # 4 receives the protection signal λ ₄ (B _P ) and outputs it via the inter-station optical transmission line 8 to the inter-station optical transmission line 8 connected to the optical XC 68 # 3.

Second Embodiment FIG. 10 is a diagram showing the configuration of an optical XC according to a second embodiment of the present invention. Components that are substantially the same as those of the optical XC in FIG. It is attached.

The optical XC according to the second embodiment is different from the optical XC according to the first embodiment in that the wavelength band for the working signal and the wavelength band for the protection signal are divided in advance, and the routing of the working signal and the protection signal is performed by the working signal. This is performed by the optical switch for protection 70 and the optical switch for protection signal 72, respectively.

Since an optical switch requires a switch element having ^two input ports, the lead amount is proportional to the ^two input ports. Therefore, by using the two optical switches, ie, the working signal optical switch 70 and the protection signal optical switch 72, the lead amount of the entire optical switch can be reduced to about half.

For the entire band λ _{1 to} λ _2n used in WDM, the bands λ _{w1 to} λ _Wn are the working signal band, and the bands λ _P1 to λ _P1 .
λ _Pn is assigned to the protection signal band. With respect to the output light of the optical demultiplexer 14, the optical signal in the working signal band of λ _{w1 to} λ _Wn is input to the working signal optical switch 70,
The optical signals in the protection signal band of λ _{P1 to} λ _Pn are input to the protection signal optical switch 72. With respect to the output light of the wavelength converter 52, the working signal is input to the working signal optical switch 70, and the protection signal is input to the protection signal optical switch 72.

The output ports of the working signal optical switch 70 and the protection signal optical switch 72 are connected to the optical multiplexer 1
8 or an optical selector 58. Optical switch 70 for working signal and optical switch 72 for protection signal
Is controlled by the controller 74. The operation system 76 sets the optical path for the working signal and the protection signal, and notifies the controller 74 of the optical path. The other components are substantially the same as the components of the first embodiment, and the description is omitted.

The operation of the light XC shown in FIG. 10 will be described below. (A) Setting of Optical Path The operation system 76 determines the working signal bands λ _{w1 to} λ _Wn and the protection signal bands λ _{P1 to} λ _Pn for the working signal and the protection signal of the optical signal output from the intra-station optical transmission line 10. The optical path is set by allocating an empty band from among the optical paths, and the optical path is notified to the controller 74 and the other optical XC which is a path of the optical path.

The operation system 76 receiving the notification
Indicates the wavelength corresponding to the optical path and the output port #j connected to the input port #i of the optical switches 70 and 72. When the controller 74 receives the notification from the operation system 76, the wavelength converter 52 and the working signal optical switch 7
0 and the protection signal optical switch 72 are controlled.

(B) Transmission of Working Signal and Protection Signal The wavelength converter 52 operates according to the control of the controller 74.
The signal is converted into the wavelength of the working signal or the protection signal, the working signal is output to the working signal optical switch 70, and the protection signal is output to the protection signal optical switch 72. The optical demultiplexer 14 separates the WDM signal light input from the inter-station optical transmission line 8 into wavelengths λ _{W1 to} λ _Wn and λ _{P1 to} λ _Pn and converts the working signals λ _{W1 to} λ _Wn to the working signal light. The signal is output to the switch 70, and the protection signals λ _{P1 to} λ _Pn are output to the protection signal optical switch 72.

The working signal optical switch 70 and the protection signal optical switch 72 output to the optical multiplexer 18 or the optical selector 58 under the control of the controller 74.
The optical multiplexer 18 multiplexes optical signals of a plurality of wavelengths and outputs the multiplexed optical signal to the inter-station optical transmission line 8. The optical selector 58 selects either the working signal or the protection signal according to the selection signal from the controller 74 and outputs the selected signal to the intra-office optical transmission line 10.

As described above, according to the second embodiment, the same effects as those of the first embodiment are obtained, and the optical switch for the working signal and the optical switch for the protection signal are divided. The configuration is simplified.

FIG. 11 is a diagram showing an optical network using the optical XC of FIG. As shown in FIG.
Of the optical XC 78 # i (i = 1 to 6). Between the optical XCs 78 # 1 and 78 # 2, between the optical XCs 78 # 1 and 78 # 6, and between the optical XCs 78 # 2 and 78 #
3, between the optical XCs 78 # 2 and 78 # 5, the optical XC 78 #
6 and 78 # 5, between the optical XCs 78 # 4 and 78 # 5, and between the optical XCs 78 # 4 and 78 # 3.
Is provided.

The operation of the optical network shown in FIG. 11 will be described below. (A) Setting of Optical Path In this example, the optical XC 78 # 1 is the transmitting end of the optical signals A and B, the optical XC 78 # 2 is the receiving end of the optical signal A, and the optical XC 78 #
3 is a receiving end of the optical signal B. Optical signal A, the working signal A _W of B, B _W, protection signal A _P, the setting of the optical path B _P performed by the operating system 76. At this time, the output wavelength of each optical signal is the wavelength at which a path can be secured end-to-end from the working signal band for the working signal and from the protection signal band for the protection signal. Assigned by system 76.

In this example, the optical path of the working signal A _W has a wavelength of λ _W1 and a route of optical XC78 # 1-optical XC # 78 #.
2. The optical path of the protection signal A _P has a wavelength λ _P1 ,
The route is optical XC78 # 1-optical XC78 # 6-optical XC78
# 5-light XC78 # 2. The optical path of the working signal B _W has a wavelength of λ _W2 and a route of optical XC78 # 1-optical XC # 7.
8 # 2-optical XC 78 # 3, the optical path of the protection signal _BP has a wavelength of λ _P2 and a route of optical XC 78 # 1-optical XC.
78 # 6-Light XC78 # 5-Light XC78 # 4-Light XC7
8 # 3.

(B) Operation of Light XC78 # 1 FIG. 12 is an explanatory diagram of the operation of light XC1 in FIG. Station
The optical signals A and B transmitted from the internal optical transmission line 10 are
Each of the working signal and protection is provided by the optical distributor 56 # 1.
Distributed to the signal. The split optical signal is converted by a wavelength converter
, According to the optical path, the working signal λ_W1(A_W), Λ_W2
(B_W), Protection signal λ_P1(A _P), Λ_P2(B
_P). Working signal λ_W1(A_W), Λ
_W2(B_W) Is input to the working signal optical switch 70 # 1.
The protection signal λ_P1(A_P), Λ _P2(B_P)
Is input to the protection signal optical switch 72 # 1.
It is.

The working signal optical switch 70 # 1 is
According to the control of the roller, the working signal λ _W1(A_W), Λ
_W2(B_W) Through the optical multiplexer 18 # 1 to the optical XC78.
Output to the inter-station optical transmission line 8 connected to # 2. Protection
Optical switch 72 # 1 is controlled by the controller.
And the protection signal λ_P1(A_P), Λ_P2(B_P)
To the optical XC78 # 6 through the optical multiplexer 18 # 1.
Output to the inter-station optical transmission line 8.

(C) Operation of Light XC78 # 2 FIG. 13 is an explanatory diagram of the operation of light XC2 in FIG. The working signal λ _W1 (A _W ), λ output from the optical XC 78 # 1
_W2 (B _W ) is transmitted through the inter-station optical transmission line 8 to the optical XC 78 #.
2 is input. Further, the protection signal λ _P1 (A _P ) output from the optical XC 78 # 1 is
The optical XC 78 # 5 and the optical XC 78
Input to # 2.

The optical demultiplexer 14 # 2 separates each wavelength into
Working signal λ_W1(A_W), Λ_W2(B_W) Is the optical signal for the working signal.
And outputs the protection signal λ_P1(A
_P) Is output to the protection signal optical switch 72 # 2.
I do. The working signal optical switch 70 # 2 receives the working signal λ._W1
(A_W) Is output to the optical selector 58 # 2, and the working signal λ _W2
(B_W) Is passed through the optical multiplexer 18 # 2 to output the light XC78 # 3.
Is output to the inter-station optical transmission line 8 connected to the.

Optical switch for protection signal 72 # 2
Converts the protection signal λ _P1 (A _P ) into an optical selector 58.
Output to # 2. The optical selector 58 # 2 outputs the working signal λ _W1 (A _W ) or the protection signal λ according to the selection signal.
_P1 (A _P ) is selected and output to the intra-office optical transmission line 10.

(D) Operation of Light XC78 # 3 FIG. 14 is an explanatory diagram of the operation of light XC3 in FIG. The working signal λ _W2 (B _W ) output from the optical XC 78 # 2 is
The signal is input to the optical XC 78 # 3 via the inter-station optical transmission line 8. Further, the protection signal λ _P2 (B _P ) output from the optical XC 78 # 1 is converted into the optical XC 78 # 6-optical XC 78 #
5-Optical XC 78 # 4, optical XC 78 # 4
78 # 3.

The optical demultiplexer 14 # 3 separates each wavelength into
The working signal λ _W2 (B _W ) is converted to the working signal optical switch 70 # 3.
And outputs the protection signal λ _P2 (B _P ) to the protection signal optical switch 72 # 3. The working signal optical switch 70 # 3 outputs the working signal λ _W2 (B _W ) to the optical selector 58 # 3, and the protection signal optical switch 72 # 3 outputs the protection signal λ _P2 (B _P ) to the optical selector 58. Output to # 3. The optical selector 58 # 3 is
According to the selection signal, either the working signal λ _W2 (B _W ) or the protection signal λ _P2 (B _P ) is selected, and the intra-station optical transmission line 10 is selected.
Output to

(E) Operation of Optical XC 78 # 5 FIG. 15 is an explanatory diagram of the operation of the optical XC 5 in FIG. light
Protection signal λ output from XC78 # 1
_P1(A_P), Λ_P2(B_P) Via the inter-station optical transmission line 8
Input to the optical XC 78 # 6. Hikari XC78 # 6
Protection signal λ _P1(A_P), Λ_P2(B_P)
Output to the optical XC 78 # 5 via the inter-station optical transmission line 8.
I do. The optical demultiplexer 14 # 5 separates the signal into optical signals of each wavelength.
And the protection signal λ_P1(A_P), Λ_P2(B_P)
The signal is output to the protection signal optical switch 72 # 5.
The protection signal optical switch 72 # 5 is
Signal λ_P1(A_P) Through the optical multiplexer 18 # 5
Output to the inter-station optical transmission line 8 to which the optical XC 78 # 2 is connected,
Protection signal λ_P2(B_P) To the optical multiplexer 18 # 5
To the inter-station optical transmission line 8 to which the optical XC78 # 4 is connected.
Power.

(F) Operation of Optical XC 78 # 4 The λ _P2 (B _P ) output from the optical XC 78 # 5 is input to the optical XC 78 # 4 via the inter-station optical transmission line 8. Light X
The C78 # 4 receives the protection signal λ _P2 (B _P ) and outputs it via the inter-station optical transmission line 8 to the inter-station optical transmission line 8 connected to the optical XC 78 # 3.

[0078]

As described above, according to the present invention,
There is no need to prepare a spare optical transmission line, and in the event of a transmission line failure, it is only necessary to switch with the optical selector of the receiving node, and high-speed failure recovery is possible.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an optical XC according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a wavelength converter in FIG. 2;

FIG. 4 is a diagram illustrating an example of an optical switch in FIG. 2;

FIG. 5 is a configuration diagram of an optical network using the optical XC of FIG. 2;

6 is an operation explanatory diagram of light XC1 in FIG. 5;

FIG. 7 is an operation explanatory diagram of light XC2 in FIG. 5;

8 is an operation explanatory diagram of light XC3 in FIG. 5;

9 is an operation explanatory diagram of light XC5 in FIG. 5;

FIG. 10 is a configuration diagram of an optical XC according to a second embodiment of the present invention.

11 is a configuration diagram of an optical network using the optical XC of FIG.

FIG. 12 is an operation explanatory diagram of light XC1 in FIG. 11;

FIG. 13 is an operation explanatory diagram of light XC2 in FIG. 11;

FIG. 14 is an operation explanatory diagram of light XC3 in FIG. 11;

FIG. 15 is an operation explanatory diagram of light XC5 in FIG. 11;

FIG. 16 is a diagram illustrating a configuration example of an optical network.

FIG. 17 is a diagram illustrating an example of a network configuration of an optical network using a plurality of optical XCs.

FIG. 18 is a diagram illustrating fixed wavelength light XC.

FIG. 19 is a diagram showing a wavelength conversion type light XC.

FIG. 20 is a diagram showing a transmission line protection method according to Prior Art 1.

FIG. 21 is a diagram showing a transmission line protection method according to the conventional technique 2.

FIG. 22 is a diagram illustrating a transmission line protection method according to the conventional technique 3.

[Explanation of symbols]

 Reference Signs List 20 optical demultiplexer 22 optical distributor 24 wavelength converter 26 optical multiplexer 28 optical selector 30 optical switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ichiro Nakajima 4-1, 1-1 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Takuji Maeda 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 Inside Fujitsu Limited (72) Isao Tsuyama Inventor 2-3-9 Shin-Yokohama, Kohoku-ku, Yokohama, Kanagawa Prefecture Fujitsu Digital Technology Co., Ltd. In-house F-term (reference) 5K002 BA05 BA06 DA02 DA09 DA13 EA33 FA01

Claims (6)

[Claims] An optical demultiplexer for separating a wavelength-division multiplexed optical signal input from each input-station optical transmission line into optical signals of each wavelength, and an optical signal input from each input-station internal optical transmission line, An optical splitter that splits the optical signal into optical signals; a wavelength converter that converts the two optical signals split from the optical splitter into optical signals of desired wavelengths and outputs a working signal and a protection signal; An optical multiplexer that multiplexes a plurality of different optical signals and outputs the multiplexed optical signal to an output inter-station optical transmission line, and a working signal and a protection signal are input. An optical selector for outputting, a plurality of input ports, a plurality of first output ports optically connected to the optical multiplexer, and a plurality of second output ports optically connected to the optical selector, output from the wavelength converter. The working signal from the input port. And output to one of the first output ports optically connected to the optical multiplexer for outputting an optical signal to the output-to-output optical transmission line corresponding to the first optical path of the working signal. And inputting the protection signal output from the wavelength converter from one of the input ports, and outputting an optical signal to the output inter-station optical transmission line corresponding to a second optical path of the protection signal. An optical signal is output to one of the first output ports optically connected to the optical multiplexer, and an optical signal output from the optical demultiplexer is output to one of the input ports.
And the optical multiplexer or the optical selector, which outputs an optical signal to the inter-output-station optical transmission line or the output-station optical transmission line corresponding to the third optical path of the optical signal. An optical switch for outputting to one of the first output port and the second output port. An optical path cross-connect device. 2. An optical demultiplexer for separating a wavelength-division multiplexed optical signal input from each input-station optical transmission line into optical signals of respective wavelengths, and an optical signal input from each input-station optical transmission line as a working signal. An optical distributor for distributing the optical signal to a protection signal; a plurality of wavelength converters for inputting the optical signal and converting the optical signal into an optical signal of a desired wavelength; and an output station for multiplexing output signals of the plurality of wavelength converters. An optical multiplexer that outputs to the inter-optical transmission line, a working signal and a protection signal are input, an optical selector that selects one of the optical signals and outputs the selected optical signal to the output intra-station optical transmission line, and a plurality of input ports, A plurality of first output ports optically connected to the wavelength converter and a plurality of second output ports optically connected to the optical selector, wherein the working signal output from the optical distributor is transmitted from one of the input ports; Input to the first optical path of the working signal An output signal is output to one of the first output ports optically connected to the wavelength converter for outputting an optical signal to the optical multiplexer corresponding to the corresponding output inter-station optical transmission line, and output from the optical distributor. The wavelength converter that inputs the protection signal from one of the input ports and outputs an optical signal to the optical multiplexer corresponding to the output-to-output optical transmission line corresponding to a second optical path of the protection signal. The optical signal output from one of the first output ports optically connected to the optical demultiplexer is input from one of the input ports, and corresponds to a third optical path of the optical signal. Corresponds to the first output port or the third optical path corresponding to the third optical path, which optically connects to the wavelength converter that outputs an optical signal to the optical multiplexer corresponding to the output inter-station optical transmission line. The optical selector is optically connected to the optical selector. Optical path cross-connect device, characterized by comprising a optical switch output to one of the second output port. 3. A plurality of optical path cross-connect devices according to claim 1 or 2, each accommodating a plurality of transmission lines between input / output stations and transmission lines within an input / output station, and the first optical device according to claim 1 or 2. 2. An optical path setting means for allocating and setting a path and a second optical path from among unused bands of the entire band, and converting the wavelengths into wavelengths allocated to the first optical path and the second optical path. 3. A wavelength converter control unit for controlling the wavelength converter according to claim 2, and the first optical path and the second optical path. 4.
An optical network, comprising: an optical switch control means for controlling the optical switch according to claim 2; and an optical selector control means for controlling the optical selector according to claim 1 or 2. 4. A plurality of demultiplexers for separating a wavelength-division multiplexed optical signal input from each input-station optical transmission line into optical signals of respective wavelengths, and an optical signal input from each input-station internal optical transmission line by two. An optical splitter that splits the optical signal into two optical signals; and converts one of the two optical signals split from the optical splitter into an optical signal having a desired wavelength in a wavelength band for the working signal, and outputs the working signal. Then, the other optical signal is converted into an optical signal of a desired wavelength in a protection signal wavelength band, and a wavelength converter that outputs a protection signal, and a plurality of optical signals having different wavelengths are multiplexed and output. An optical multiplexer that outputs to the inter-station optical transmission line, an optical selector that receives the working signal and the protection signal, selects one of the optical signals, and outputs the selected optical signal to the output intra-station optical transmission line, and a plurality of input ports. A first output port optically connected to the optical multiplexer; Has a serial optical selector and a second output port for optical connection, the current signal output from the wavelength converter and than one input of the input port, first the developing signal
One of the first output ports optically connected to the optical multiplexer for outputting an optical signal to the optical path between the output stations corresponding to an optical path.
And an optical signal in a wavelength band for a working signal output from the optical demultiplexer is input from one of the input ports, and is output between the output stations corresponding to a second optical path of the optical signal. A working signal optical switch for outputting to one of the first output port or the second output port optically connected to the optical multiplexer or the optical selector for outputting an optical signal to an optical transmission path or the optical transmission path in the output station. And a plurality of input ports, a third output port optically connected to the optical multiplexer, and a fourth output port optically connected to the optical selector, wherein the protection port output from the wavelength converter is input to the input port. And outputs the signal to one of the third output ports optically connected to the optical multiplexer that outputs an optical signal to the output-to-output optical transmission line corresponding to the third optical path of the protection. Output from the optical demultiplexer. The optical signal of the wavelength band for the protection signal obtained is input from one of the input ports, and the optical signal is transmitted to the optical transmission path between output stations or the optical transmission path in the output station corresponding to the fourth optical path of the optical signal. A protection signal optical switch for outputting to one of the third output port or the fourth output port optically connected to the optical multiplexer or the optical selector for outputting a signal. Cross-connect device. 5. A plurality of demultiplexers for separating a wavelength-division multiplexed optical signal input from each input-to-station optical transmission line into optical signals of respective wavelengths, and an optical signal input from each intra-station optical transmission line to a working signal. And a plurality of wavelength converters that input the optical signal and convert the optical signal into an optical signal having a wavelength in a wavelength band for a desired working signal or a wavelength band for a protection signal, and the plurality of wavelength converters. An optical multiplexer for multiplexing the output signal of the wavelength converter and outputting the multiplexed signal to the optical transmission line between the output stations; and a working signal and a protection signal are input. A plurality of input ports, a first output port optically connected to the wavelength converter, and a second output port optically connected to the optical selector, and the working output from the optical distributor. Signal to the input port And than one input, the first the developing signal
An optical demultiplexer for outputting an optical signal to one of the first output ports optically connected to the wavelength converter for outputting an optical signal to the optical multiplexer corresponding to the optical transmission path between output stations corresponding to an optical path; The optical multiplexer corresponding to the output inter-station optical transmission line corresponding to the second optical path of the optical signal, wherein the optical signal in the wavelength band for the working signal output from the optical signal is input from one of the input ports. The first optically connected to the wavelength converter that outputs an optical signal to the first
A working signal optical switch for outputting to one of the second output ports optically connected to the optical selector corresponding to the output port or the output intra-office optical transmission line corresponding to the second optical path, and a plurality of input ports; A third output port optically connected to the wavelength converter and a fourth output port optically connected to the optical selector, wherein the protection signal output from the optical distributor is input from one of the input ports; Outputting the optical signal to one of the third output ports optically connected to the wavelength converter for outputting an optical signal to the optical multiplexer corresponding to the output optical path corresponding to the third optical path of the protection. Inputting an optical signal of a wavelength band for a protection signal output from the optical demultiplexer from one of the input ports, to the output inter-station optical transmission line corresponding to a fourth optical path of the optical signal; Before responding The third output port or the fourth output port optically connected to the wavelength converter that outputs an optical signal to the optical multiplexer.
An optical switch for a protection signal for outputting to one of the fourth output ports optically connected to the optical selector corresponding to the optical transmission path in the output station corresponding to an optical path. Connect device. 6. A plurality of optical path cross-connect devices according to claim 4 or 5, each accommodating a plurality of transmission lines between input / output stations and transmission lines within an input / output station, and the first light according to claim 4 or 5. A first optical path setting means for allocating and setting a path from a wavelength band for a working signal, and setting and dividing a third optical path according to claim 4 or 5 from a wavelength band for a protection signal. 6. A second optical path setting unit that performs the conversion, and a wavelength converter control unit that controls the wavelength converter according to claim 4 or 5 so as to convert the wavelength into a wavelength assigned to the first optical path and the third optical path. A first switch control means for controlling the working signal optical switch according to claim 4 or 5 according to the first optical path, and controlling the protection signal optical switch according to claim 4 or 5 according to the third optical path. 2nd switch Optical network to the control means, the optical selector control means for controlling the optical selector according to claim 4, characterized by comprising a.