JP2002262319A - Optical communication network and optical path cross connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication network that enhances routing processing capability so as to attain a high capacity while suppressing the increase in the entire cost with a configuration that a wavelength path sent through a wavelength multiple transmission link is subjected to routing processing on the basis of its wavelength and to provide an optical path cross connector that conducts the routing processing in the optical communication network. SOLUTION: In the optical communication network provided with a plurality of the optical path cross connectors and the wavelength multiple transmission link interconnecting them where a wavelength path led to the wavelength multiple transmission link is subjected to the routing processing by the optical path cross connector on the basis of its wavelength, each optical path cross connector is configured such that the wavelength paths of the link are divided into wavelength group of N-sets (N is an integer of 2 or over) consisting of G-sets each (G is an integer of 2 for over) of the wavelength paths of the wavelength multiple transmission link, and applies the routing processing in the unit of the wavelength group paths.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication network in which a wavelength path transmitted through a wavelength division multiplex transmission link is routed based on its wavelength, and an optical path cross-connect device for performing a routing process in the optical communication network. About.

[0002]

2. Description of the Related Art Due to an increase in data communication traffic such as the Internet, it is required to introduce a routing processor having a Tbit / s class at present, and a throughput of 10 to 100 Tbit / s or more in the near future. The current routing processing device converts information transferred via a large-capacity optical fiber transmission line into an electric signal at an input stage, reads transfer destination information for each frame of transfer information, and addresses corresponding to each transfer destination. Is controlled with reference to the routing table storing the information, and the forwarding process is performed based on the route information. Then, after competing control is performed by a buffering operation, the electric signal is converted into an optical signal and transmitted to the next-stage optical fiber transmission line.

In a conventional routing processing device that processes according to such a procedure, it is difficult to change the frame structure of transfer information, and it is essentially difficult to provide various services according to the needs of the user.

Further, in order to increase the processing speed, it is required to increase the speed of an LSI circuit for executing electrical processing and increase the degree of parallelism. In particular, the recent increase in data communication traffic has exceeded the progress of high-speed LSI circuits, and therefore, an increase in the degree of parallelism, that is, an increase in the number of switching routes of the routing processing device, cannot be avoided. However, an increase in the degree of parallelism causes not only hardware issues such as mounting, but also a decrease in transfer processing efficiency.
It is difficult to obtain the expected effects.

As a means for solving such a problem, there is an optical path cross connect (OPXC) that uses the wavelength of an optical signal to be transferred as routing information. In this optical path cross connect, an input optical signal is spatially separated for each wavelength channel, and a switching process is performed for each wavelength channel. That is, since the optical signal transmitted through the optical fiber transmission line is processed without being converted into an electric signal, it is advantageous for reducing the device scale and increasing the capacity.

[0006]

The optical path cross-connect device requires a number of wavelength conversion elements proportional to the number of wavelength channels and an optical matrix switch having a scale proportional to the square of the number of wavelength channels. In addition, when the size of the optical matrix switch is increased, it is required to reduce the loss while improving the uniformity of the switch manufacturing technology. But,
At present, the unit price of the optical switch is much higher than that of the electric switch, and there is a problem that the increase in the size of the optical matrix switch impairs the cost metric of the optical path cross-connect device.

According to the present invention, in a configuration in which a wavelength path transmitted through a wavelength division multiplex transmission link is routed based on its wavelength, the routing processing capacity is increased, and the capacity can be increased while suppressing an increase in the overall cost. It is an object of the present invention to provide an optical communication network and an optical path cross-connect device for performing a routing process in the optical communication network.

[0008]

According to a first aspect of the present invention, there are provided a plurality of optical path cross-connect devices and a wavelength division multiplex transmission link connecting between the devices, and the wavelength path transmitted through the wavelength division multiplex transmission link is an optical path. In an optical communication network in which a routing process is performed by a cross-connect device based on its wavelength, an optical path cross-connect device has N wavelength paths (G is an integer of 2 or more) of N wavelengths (N is 2). This is a configuration in which a wavelength group path is divided into the above (integers) and routing processing is performed in units of the wavelength group path.

According to a second aspect of the present invention, the optical communication network according to the first aspect is divided into sub-regions 1 to z (z is an integer of 2 or more), and a wavelength to be routed for each sub-region. , Nz of the group paths, the numbers G1, G2,..., Gz of the wavelength paths constituting each wavelength group path, the number N0 of the wavelength group paths routed between the respective sub-regions, and The number G0 of the wavelength paths constituting the wavelength group path is set independently of each other (N0 to Nz are integers of 2 or more, G0
-Gz is an integer of 2 or more). As a result, it is possible to design an optical communication network according to the traffic demand of each sub-region, and it is possible to increase the efficiency of using finite optical frequency resources in the wavelength multiplexing transmission link and the optical path cross-connect device.

According to a third aspect of the present invention, in the optical communication network according to the first or second aspect, each of G (G0 to Gz) wavelength groups constituting N (N0 to Nz) wavelength group paths. The wavelengths of the wavelength paths are λ1,1 to λ1, G, λ2,1 to λ2, G,.
When λN, 1 to λN, G, [λ1,1 to λ1, G], [λ
2,1 to λ2, G],..., [ΛN, 1 to λN, G] are continuously arranged on the wavelength axis.

According to a fourth aspect of the present invention, in the optical communication network according to the first or second aspect, each of G (G0 to Gz) wavelength groups constituting N (N0 to Nz) wavelength group paths. The wavelengths of the wavelength paths are λ1,1 to λ1, G, λ2,1 to λ2, G,.
When λN, 1 to λN, G, [λ1,1 to λ1, G], [λ
[Λ1,1 to λN, G] are arranged at equal wavelength intervals on the wavelength axis, and [λ1,1 to λN,
1], [λ1,2 to λN, 2],..., [Λ1, G to λN, G] are respectively continuously arranged on the wavelength axis.

According to a fifth aspect of the present invention, in the optical communication network according to the first or second aspect, each of G (G0 to Gz) wavelength groups constituting N (N0 to Nz) wavelength group paths. The wavelength paths are 1 to G (1 to G0,
1 to G1, 1 to G2,..., 1 to Gz). As a result, the communication bandwidth can be flexibly accommodated according to the communication demand between the terminals. As a result, the utilization efficiency of the finite optical frequency resources can be increased.

According to a sixth aspect of the present invention, in the optical communication network according to the fifth aspect, 1 to G (1 to G0, 1 to G1, 1 to G) constituting N (N0 to Nz) wavelength group paths, respectively. 1-G2,
, 1 to Gz) The wavelengths of the wavelength paths are denoted by λ1,1 to λ1, g.
1, λ2,1 to λ2, g2,..., ΛN, 1 to λN, gn (g1 to gn are 1 to G (1 to G0,1 to G1,1 to G2, ...,
1 to Gz), [λ1,1 to λ1, g1], [λ2,1 to
[λ2, g2],..., [λN, 1 to λN, gn] are continuously arranged on the wavelength axis. This facilitates processing such as collectively wavelength-converting a plurality of wavelength paths constituting a wavelength group path, which is a routing processing unit, and also facilitates the configuration of a multiplexer / demultiplexer.

According to a seventh aspect of the present invention, in the optical communication network according to the first or second aspect, the monitoring unit of the optical signal transmitted through the wavelength division multiplexing transmission link is a wavelength group which is a unit of a routing process. Path. As a result, the routing processing unit and the monitoring unit become the same, and the operation of network failure detection and reconfiguration can be simplified. Further, by monitoring in units of routing processing, the size of the monitoring device can be reduced as compared with the case where monitoring is performed in units of wavelength paths.

According to an eighth aspect of the present invention, there is provided an optical path cross-connect for inputting a wavelength path to be transmitted through a plurality of wavelength division multiplex transmission links, performing routing processing based on the wavelength, and outputting to a corresponding wavelength division multiplex transmission link. In the apparatus, a plurality of duplexers for inputting wavelength paths of each wavelength multiplexing transmission link and separating them into N (N is an integer of 2 or more) wavelength group paths by G (G is an integer of 2 or more). Routing processing means for performing routing processing for each wavelength group path as a unit, and a plurality of multiplexers for multiplexing for each wavelength division multiplexing transmission link that outputs each wavelength group path routed by the routing processing means. You.

According to a ninth aspect of the present invention, in the optical path cross-connect device according to the eighth aspect, a plurality of duplexers,
A routing processing means, a plurality of optical path cross-connect processing sections composed of a plurality of multiplexers are provided, hierarchized, one demultiplexer and one multiplexer are sequentially connected between the layers, and the remaining The wavelength division multiplexing transmission link is connected to each of the demultiplexer and the multiplexer.

According to a tenth aspect of the present invention, in the optical path cross-connect device according to the ninth aspect, the number of wavelength-division multiplexing transmission links, the number of wavelength group paths, and the number of wavelength groups connected to the optical path cross-connect processing unit of each layer The wavelength paths that make up the path are
The configuration is set independently of each other.

According to an eleventh aspect of the present invention, in the optical path cross-connect device according to the eighth or ninth aspect, the routing processing means wavelength-converts a plurality of wavelength paths constituting the wavelength group path. And an optical matrix switch for routing the wavelength-converted wavelength group path.

According to a twelfth aspect of the present invention, in the optical path cross-connect device according to the eleventh aspect, the wavelength converter performs an optical parametric wavelength conversion of a plurality of wavelength paths constituting a wavelength group path collectively. It is a converter.

According to a thirteenth aspect of the present invention, in the optical path cross-connect device according to the twelfth aspect, the optical parametric wavelength converter includes an optical filter for removing an input wavelength path and noise light.

According to a fourteenth aspect of the present invention, in the optical path cross-connect device according to the twelfth aspect, the optical parametric wavelength converter includes two output ports of a two-input two-output first optical multiplexer / demultiplexer. A nonlinear Mach-Zehnder interferometer in which an optical dispersion medium and a secondary optical nonlinear medium are inserted into two optical paths respectively connecting two input ports of a second optical multiplexer / demultiplexer having two inputs and two outputs; In one optical path between the first optical multiplexer / demultiplexer and the second optical multiplexer / demultiplexer, a first secondary optical nonlinear medium is inserted after the first optical dispersion medium, and the other optical path is inserted. A second optical dispersion medium is inserted next to the second secondary optical nonlinear medium in the path, and signal light and wavelength conversion light constituting a wavelength group path from one input port of the first optical multiplexer / demultiplexer. The multiplexed light of the pumping light which is the source of the second optical multiplexer / demultiplexer is inputted. In this configuration, the signal light and the pump light are output from the output port, and the wavelength group path converted from the wavelength group path input from the other output port is output.

According to a fifteenth aspect of the present invention, in the optical path cross-connect device according to the eighth or ninth aspect, the demultiplexer and the multiplexer are arrayed waveguide diffraction devices having periodic transmission wavelength characteristics. It is a grating type multiplexer / demultiplexer (AWG).

According to a sixteenth aspect of the present invention, in the optical path cross-connect device according to the eighth or ninth aspect, the duplexer and the multiplexer have an arrayed waveguide diffraction having a periodic transmission wavelength characteristic. In this configuration, a grating type multiplexer / demultiplexer (AWG) is used in a two-stage configuration, and an optical gate switch for selectively transmitting or blocking each wavelength path demultiplexed therebetween is provided.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Basic Configuration of Optical Path Cross-Connect Device) FIG. 1 shows a basic configuration of an optical path cross-connect device according to the present invention. In the figure, a plurality of wavelength division multiplexing transmission links 20 are connected to an optical path cross-connect device 10. The optical path cross-connect device 10 separates the wavelength path of each wavelength multiplexing transmission link 20 into N (N is an integer of 2 or more) wavelength group paths by G (G is an integer of 2 or more) wavelength splitters 11. And a routing processing unit 12 for performing a routing process in units of the wavelength group paths, and a multiplexer 13 for multiplexing the wavelength group paths to be output to each wavelength multiplexing transmission link 20.

FIG. 2 shows the difference between the conventional configuration of the optical path cross-connect device and the configuration of the present invention. In the conventional configuration, the routing process is performed in units of wavelength paths, and therefore, for example, a 16 × 16 routing processing unit is required to route 16 wavelength paths. On the other hand, in the configuration of the present invention, the routing process is performed in units of wavelength group paths obtained by grouping a plurality of wavelength paths. Therefore, if a wavelength group path is configured by four wavelength paths, 16 wavelength paths are routed. Can be handled by a 4 × 4 routing processing unit. Since the routing processing unit 12 includes a wavelength converter and an optical matrix switch as described later, the circuit scale can be significantly reduced by using a wavelength group path as a routing processing unit.

Here, the wavelengths of the wavelength paths constituting each wavelength group path are [λ1,1 to λ1, G], [λ2,1 to λ2, G],.
[λN, 1 to λN, G]. Here, i of the wavelength λi, j indicates the wavelength group number 1 to N to which the wavelength belongs, and j indicates the wavelength number 1 to G.

FIG. 3 shows an example of wavelength arrangement of a wavelength group path.
In the example of the wavelength arrangement shown in FIG. 3A, the wavelengths [λ1,1 to λ1, G], [λ2,1 to λ]
, [G], ..., [λN, 1 to λN, G] are continuously arranged on the wavelength axis.

In the wavelength allocation example shown in FIG. 3B, the wavelengths [λ1,1 to λ1, G] of the wavelength paths constituting the wavelength group paths 1 to N,
[λ2,1 to λ2, G],..., [λN, 1 to λN, G] are arranged at equal wavelength intervals on the wavelength axis, and [λ1,1 to
[λN, 1], [λ1,2 to λN, 2],..., [λ1, G to λN, G] are continuously arranged on the wavelength axis. As the demultiplexer 11 and the demultiplexer 13 for performing the wavelength division path multiplexing / demultiplexing, for example, an arrayed waveguide diffraction grating type optical multiplexing / demultiplexing device (AWG) having periodic multiplexing / demultiplexing characteristics is used. be able to.

The wavelength arrangement example shown in FIG. 3C is an example in which the number of wavelength paths constituting each wavelength group path is variably set within a range of 1 to G wavelengths. Wavelengths [λ1,1 to λ1, g1], [λ2,1 to λ2, g2] of the wavelength paths constituting the wavelength group paths 1 to N,.
[λN, 1 to λN, gn] are continuously arranged on the wavelength axis. Here, g1 to gn are integers in the range of 1 to G. A demultiplexer 11 that performs multiplexing / demultiplexing of such a wavelength group path.
The multiplexer 13 can be configured using two AWGs and an optical gate switch that performs on / off operation. FIG. 4 shows an example of the configuration.

In FIG. 4, a demultiplexer 11 is an optical star coupler 111 for N-branching the wavelength multiplexed signal light of the wavelength multiplexing transmission link 20 and a demultiplexer for demultiplexing each of the N-branched wavelength multiplexed signal lights. AWGs 112-1 to 112-N and optical gate switch groups 113-1 to 113-N for individually turning on / off each wavelength path demultiplexed for each AWG output
And AWGs 114-1 to 114-N as multiplexers for multiplexing the wavelength paths output from the respective optical gate switch groups. As shown in FIG. 3 (3), the wavelength paths constituting each wavelength group path can be variably set according to the wavelength path turned on by the optical gate switch group. The multiplexer 13 can be realized by a configuration in which the arrangement in FIG. 4 is reversed.

(First Embodiment of Optical Communication Network) FIG. 5 shows a first embodiment of the optical communication network of the present invention. In the figure,
The optical communication network according to the present embodiment includes 36 optical path cross-connect devices 10 and 59 wavelength multiplexing transmission links 20 connecting them, and the optical path cross-connect device 10 uses a wavelength group path as a unit. A routing process is performed.

FIG. 6 shows the difference between the conventional configuration of the optical communication network and the configuration of the present invention. In the conventional configuration, since the routing process is performed for each wavelength path, it is necessary to individually handle a plurality of wavelength paths transferred to the same destination (IP router). On the other hand, in the configuration of the present invention, since the routing process is performed for each wavelength group path, the same destination (IP router)
Can be grouped and routed collectively.

In the configuration of the present invention, for example, the number of wavelength paths of the wavelength division multiplexing transmission link 20 is 65, the optical frequency interval of each wavelength path is 50 GHz (the wavelength interval is about 0.4 nm), and the wavelength is 1530 to 15 nm.
It is arranged in the C band of 60 nm, and the signal speed is 10 Gbit / s and 2.5 Gbit / s. Here, 1 for 4 wavelength paths
When one wavelength group path, which is one routing processing unit, is configured, 16 wavelength group paths are configured, and the remaining one wavelength path includes signal quality information for each wavelength group path, an optical path cross-connect device, a relay device, and the like. It is used as a supervisory signal channel having supervisory control information.

FIG. 7 shows a configuration example of the wavelength division multiplexing transmission link 20. In the figure, in the wavelength multiplex transmission link 20, in order to suppress self-phase modulation of each wavelength path and four-wave mixing between each wavelength path, which are problems in wavelength multiplex transmission,
One transmission section is constituted by the core expanded fiber 21 in which the nonlinearity of the transmission optical fiber is suppressed and the dispersion compensating fiber 22 in which the dispersion and the dispersion slope of the core expanded fiber 21 are compensated, and each transmission section compensates for the loss of the optical fiber. The configuration is such that the connection is made via an optical fiber amplifier 23. For example, if the wavelength division multiplexing transmission link 20 is composed of 3 to 4 transmission sections and one transmission section is 80 km, 240 to 360 km
The optical path cross-connect devices 10 are arranged at intervals of.

As the optical fiber amplifier 23, an optical amplifier using an erbium-doped optical fiber and a Raman optical amplifier using the transmission optical fiber itself as an optical amplification medium are used.

FIG. 8 shows a configuration example of the optical path cross-connect device 10 used at the point A in the optical communication network of FIG. In the figure, in an optical path cross-connect device 10 at a point A, four optical fibers 16-1 serving as a wavelength division multiplexing transmission link 20 from four adjacent optical path cross-connect devices.
Through 16-4 (16'-1 to 16'-4), and 64 wavelength paths and one wavelength path for monitoring (total of 65 wavelength paths).
), And 64 wavelength paths and one wavelength path for monitoring (total 65) from the transmitting / receiving unit 17 of the own device via the optical fiber 16-5 (16'-5) for add / drop. To accommodate.

The input ports to which the optical fibers 16-1 to 16-5 are connected are connected to the demultiplexers 11-1 to 11-5 for separating the wavelength groups into paths. Demultiplexer 11-1 to 1
1-4 splits each of the 64 wavelength paths input from the optical fibers 16-1 to 16-4 into four 16 wavelength group paths, and the splitter 11-5 splits the optical fiber 16-5. The 64 wavelength paths for transmission, which are input from, are divided into 16 wavelength group paths by four. For example, the wavelengths of the wavelength paths of the wavelength group paths separated by the demultiplexer 11-1 are [λ1,1 to λ1,4], [λ2,
1 to λ2,4], ..., [λ16,1 to λ16,4].

A total of 80 wavelength group paths separated into 16 by the demultiplexers 11-1 to 11-5 are combined with the wavelength converter 14.
Then, the input signal is input to the routing processing unit 12 composed of the 80 × 80 optical matrix switch 15, and the necessary wavelength conversion and routing processing are performed. The outputs of the optical matrix switch 15 are multiplexed by the multiplexers 13-1 to 13-5 for each of the 16 wavelength group paths, and output from the output ports to the optical fibers 16'-1 to 16'-5. . Each of the optical fibers 16'-1 to 16'-4 has 64 fibers (25 in total).
6) are output, and 64 wavelength paths for reception are output to the optical fiber 16'-5.

The wavelength path of the supervisory signal channel separated by the demultiplexers 11-1 to 11-5 is input to the controller 18. The controller 18 controls each wavelength converter 1 according to the control information transmitted through the monitor signal channel.
4 and the operation of the optical matrix switch 15 are controlled. Further, the controller 18 generates a monitor signal channel on which new control information of each wavelength group path is placed, and inputs the monitor signal channel to the multiplexers 13-1 to 13-5 to multiplex.

The routing processing unit 12 shown in the present embodiment has a configuration in which each wavelength group path is wavelength-converted by the wavelength converter 14 and then input to the optical matrix switch 15. The wavelength group path that is switched by the matrix switch 15 and output is converted to the wavelength converter 1
4 may be configured to perform wavelength conversion.

FIG. 9 shows a configuration example of the transmission / reception unit 17. In the figure, a transmission / reception unit 17 is an electro-optical converter (E / O) that converts an electric signal output from each IP router into an optical signal.
31-1 to 31-65 and a crossbar switch 32 for connecting each electric signal to an electro-optical converter having a wavelength corresponding to a transfer destination.
And a multiplexer 33 for multiplexing the optical signals of each wavelength and outputting the multiplexed optical signals to the optical fiber 16-5, and a demultiplexer for separating the optical wavelength multiplex signal input from the optical fiber 16'-5 into optical signals of each wavelength. Vessel 3
4 and an opto-electric converter (O) for converting each optical signal into an electric signal.
/ E) 35-1 to 35-65, and each electric signal is
The crossbar switch 36 is connected to the P router.

FIG. 10 shows a configuration example of the optical matrix switch 15. FIG. 10A shows a first configuration example, and FIG. 10B shows a second configuration example. In FIG. 10A, the optical matrix switch 15 includes a 80 × 80 mechanically operated reflector switch 40. This reflector switch 40
Is controlled by the controller 18 shown in FIG.
For example, to output the wavelength group path of port a to port b, the mirror switch 40a which is the intersection of the matrix
Only b is turned on, and the mirror switches in the row and column are turned off.

In FIG. 10 (2), the optical matrix switch 15 is realized by 16 × 5 optical switches 150-1 to 150-5 for routing in wavelength group path units and mesh wiring. When the 80 × 80 optical matrix switch 15 is used, the wavelength group paths output to the optical fibers are multiplexed by the multiplexers 13-1 to 13-5. Each of the switches 150-1 to 150-5 is configured to route and combine wavelength group paths output to each optical fiber. That is, the 16 × 5 optical switches 150-1 to 150-5 have a configuration in which 16 × 5 matrix wiring is performed via the 1 × 2 optical switch 151, and the multiplexer 152 multiplexes the optical fiber corresponding to each optical fiber. is there. As a result, the number of input ports of the multiplexers 13-1 to 13-5 becomes 16
From 5 to 5.

(Example of Configuration of Wavelength Converter 14) FIG. 11 shows a first example of the configuration of the wavelength converter 14. In the figure, a wavelength converter 14 includes a demultiplexer 41 for separating an input wavelength group path into four wavelength paths, wavelength tunable laser light sources 42-1 to 42-4 set to conversion wavelengths, A wavelength conversion element 43-1 to 43-4 for converting the path into an electric signal and modulating the output light of each tunable laser light source with the electric signal;
It is composed of a multiplexer 44 that multiplexes each wavelength-converted light and outputs the multiplexed light as a wavelength group path. Note that, as the wavelength conversion element 43 used here, a module in which a single traveling photocarrier diode capable of high-speed response and an EA modulator can be used can be used.

FIG. 12 shows a second configuration example of the wavelength converter 14. In the figure, a wavelength converter 14 includes a demultiplexer 41 for separating an input wavelength group path into four wavelength paths, and wavelength tunable laser light sources 42-1 to 42 set to conversion wavelengths.
-4, wavelength conversion elements 45-1 to 45-4 for directly modulating the output light of each tunable laser light source in each wavelength path, and a multiplexer for multiplexing each wavelength conversion light and outputting it as a wavelength group path. 4
4.

As the wavelength conversion element 45 used here,
Semiconductor optical amplifiers 46-1 and 46-2 having a Mach-Zehnder interferometer configuration shown in FIG. The control light output from the wavelength tunable laser light source 42 is
The semiconductor optical amplifiers 46-1 and 46-2 are branched into two at 7-1.
, And are combined and output by the other optical coupler 47-2. Here, when the signal light (wavelength path) is input to one of the semiconductor optical amplifiers 46-1, the refractive index changes, and the phase of the passing control light changes. Therefore, the phases of the respective control lights combined by the optical coupler 47-2 are different, and the phase change appears as the intensity change. That is, information of the signal light is carried on the control light, and wavelength conversion from the wavelength of the signal light to the wavelength of the control light is performed. The wavelength conversion element 45 having such a configuration can operate at high speed because it does not include an electric circuit and an electric element.

The wavelength conversion element 45 has a configuration using cross-phase modulation of a semiconductor optical amplifier, and can output signal light and wavelength-converted light separately to different ports. On the other hand, when a configuration using cross gain modulation of a semiconductor optical amplifier is used, an optical filter that separates signal light and noise light from wavelength-converted light is used.

FIG. 13 shows a third configuration example of the wavelength converter 14. The feature of this configuration is that an optical parametric wavelength converter that collectively converts the wavelengths of the wavelength group paths without separating the wavelength group paths into respective wavelength paths (refer to Japanese Patent Application Laid-Open No. 2006-163873).
000-304936). Accordingly, not only the optical matrix switch 15 but also the wavelength converter 14 can be integrated in units of wavelength group paths, and the configuration of the optical path cross-connect device can be simplified. Here, a wavelength group path to be subjected to wavelength conversion is referred to as signal light, and light serving as a source of the wavelength converted light is referred to as pump light.

In the figure, the wavelength converter 14 has an internal 2
The optical path is constituted by a nonlinear Mach-Zehnder interferometer having a light dispersion medium and a second-order optical nonlinear medium, respectively. However, in the two optical paths, the order of the light dispersion medium and the second-order optical nonlinear medium is reversed.

The signal light and the pump light are multiplexed by the WDM coupler 51, and the multiplexed light is input from one input port of the optical multiplexer / demultiplexer 52 and branched into two optical paths. The multiplexed light branched to one optical path is first input to the light dispersion medium 53, and then input to the second-order optical nonlinear medium 54. The multiplexed light branched to the other optical path is first input to the second-order optical nonlinear medium 55, and then to the light dispersion medium 56. The wavelength-converted light generated in the second-order optical nonlinear media 54 and 55, the signal light and the pump light passing through the two optical paths are multiplexed by the optical multiplexer / demultiplexer 57, and the signal light and the pump light are output to one output port. Is output, and the wavelength-converted light is output to the other output port.

FIG. 14 shows a configuration example of the light dispersion media 53 and 56 and the second-order optical nonlinear media 54 and 55. Here, L
On the iNbO ₃ substrate 60, non-quasi-phase matched LiNbO ₃ waveguides 61 and 62 as light dispersion media 53 and 56 and quasi-phase matched LiNbO ₃ waveguides 63 and 64 as second-order optical nonlinear media 54 and 55 are monolithic. To be configured. The quasi-phase-matched LiNbO ₃ waveguides 63 and 64 are provided on the LiNbO ₃ substrate 6.
0, a domain-inverted region is formed at a predetermined interval by applying a voltage at the time of fabrication, and titanium (Ti) is diffused to form two LiNb layers.
An O ₃ waveguide is formed. On the other hand, in the ordinary LiNbO ₃ waveguide, the propagation coefficient differs greatly between the pumping light and the signal light, and this property is used as a light dispersion medium, and the non-pseudo phase matching Li is used.
These are used as NbO ₃ waveguides 61 and 62. Thereby, the light dispersion medium and the optical nonlinear medium can be integrated.

(Second Embodiment of Optical Communication Network) FIG.
2 shows a second embodiment of the optical communication network of the present invention. In the figure, an optical communication network according to the present embodiment includes a backbone network 71 and a regional network 72.
It has a two-layer network structure separated into -1 to 72-4. The backbone network 71 is composed of 16 optical path cross-connect devices 10 and a wavelength division multiplexing transmission link 20 connecting them, and performs a routing process for each wavelength group path.

For example, the number of wavelength paths of the wavelength division multiplexing transmission link 20 is 129, the optical frequency interval of each wavelength path is 50 GHz (the wavelength interval is about 0.4 nm), and the wavelength is arranged in the C band and the L band of 1530 to 1580 nm. Speed is 10Gbit / s and
2.5 Gbit / s. Here, when a wavelength group path, which is one routing processing unit, is configured by four wavelength paths,
Thirty-two wavelength group paths are configured, and the remaining one wavelength path is used as a monitoring signal channel having signal quality information for each wavelength group path and monitoring control information of an optical path cross-connect device and a relay device.

Each of the local networks 72-1 to 72-4 employs various network topologies such as a ring, a mesh, and a star according to the local circumstances. here,
For each optical path cross-connect device of the regional network, a device that performs routing processing in units of conventional wavelength paths is used, and the number of wavelength paths of the wavelength multiplexing transmission link 20 is 32. Note that the same applies to a case where routing processing is performed for each wavelength group path in a regional network.

FIG. 16 shows a configuration example of the optical path cross-connect device 10 used at the point B of the optical communication network of FIG. In the figure, an optical path cross-connect device 10 at a point B connecting a backbone network 71 and a local network 72-1 has a two-layer structure of a backbone network corresponding unit 73 and a local network corresponding unit 74 in accordance with the two-layer structure of the optical communication network. It has become.

In the backbone network unit 73, two optical fibers 16-n are connected by two adjacent optical path cross-connect devices.
129 wavelength paths are accommodated through the optical fiber 16-3 (16'-3) via the optical fiber 16-3 (16'-3). Accommodates 129 wavelength paths.

The input ports to which the optical fibers 16-1 to 16-3 are connected are connected to the demultiplexers 11-1 to 11-3 for demultiplexing into wavelength group paths. Demultiplexer 11-1, 1
1-2 splits each of the 128 wavelength paths of the optical fibers 16-1 and 16-2 into 32 wavelength group paths of 4 each, and the splitter 11-3 controls the maximum of the optical fiber 16-3. The 128 wavelength paths are separated into a maximum of 32 wavelength group paths by four. For example, the wavelengths of the wavelength paths of each wavelength group path separated by the demultiplexer 11-1 are [λ1,1 to λ1,4], [λ2,1 to λ2,4],
…, [Λ32,1 to λ32,4].

A total of 96 wavelength group paths separated into 32 by the demultiplexers 11-1 to 11-3 are combined with the wavelength converter 14.
a and a 96 × 96 optical matrix switch 15a, and are input to a routing processing unit 12a, where necessary wavelength conversion and routing processing are performed. The output of the optical matrix switch 15a is connected to the multiplexers 13-1 to 13-3.
Are multiplexed for each of the 32 wavelength group paths, and output from the output ports to the optical fibers 16'-1 to 16'-3. The optical fibers 16'-1 and 16'-2 each have 12
Eight (256 in total) wavelength paths are output, and a maximum of 128 wavelength paths are output to the local network corresponding unit 74 on the optical fiber 16'-3.

The wavelength path of the supervisory signal channel separated by the demultiplexers 11-1 to 11-3 is determined by the controller 18a.
Is input to The controller 18a determines the conversion wavelength of each wavelength converter 14a and the optical matrix switch 15a in accordance with the control information transmitted by the monitor signal channel.
Control the operation of. Further, the controller 18a generates a supervisory signal channel carrying new control information of each wavelength group path, and inputs the supervisory signal channel to the multiplexers 13-1 to 13-3 to multiplex.

In the local network corresponding section 74, the backbone network corresponding section 73
12 through the optical fiber 16-3 (16'-3).
Eight wavelength paths are accommodated, and two optical fibers 16-5 and 16-6 are connected from two adjacent optical path cross-connect devices.
32 wavelength paths are accommodated through (16'-5, 16'-6), respectively, and transmitted and received from the transmission / reception unit 17 of the own apparatus via the add / drop optical fiber 16-7 (16'-7). Accommodates a number of wavelength paths.

Optical fibers 16'-3, 16-5 to 16-
7 are connected to demultiplexers 11-4 to 11-7, which separate the input ports into units of wavelength paths. Duplexer 11
-4 separates up to 128 wavelength paths of the optical fiber 16'-3, and the demultiplexers 11-5 to 11-7 connect the optical fiber 1 '
Each of 32 wavelength paths 6-5 to 16-7 is separated.

The wavelength path separated into a maximum of 128 wavelengths by the demultiplexer 11-4 and a total of 96 wavelength paths separated into 32 wavelengths by the demultiplexers 11-5 to 11-7 are combined into a wavelength converter 14b. The signal is input to the routing processing unit 12b including the optical matrix switch 15b, and necessary wavelength conversion and routing processing are performed. Optical matrix switch 1
The output of 5b is multiplexed with wavelength paths by multiplexers 13-4 to 13-7, respectively, and the optical fiber 16-
3, 16'-5 to 16'-7. Up to 128 wavelength paths are output to the optical fiber 16-3, and 32 wavelength paths are output to the optical fibers 16'-5 and 16'-6 (total of 64 paths).
), And 32 wavelength paths are output to the optical fiber 16'-7 for reception.

The wavelength path of the supervisory signal channel separated by the demultiplexers 11-4 to 11-7 is determined by the controller 18b.
Is input to The controller 18b determines the conversion wavelength of each wavelength converter 14b and the optical matrix switch 15b in accordance with the control information transmitted by the monitor signal channel.
Control the operation of. Further, the controller 18b generates a supervisory signal channel carrying new control information of each wavelength group path, and inputs the supervisory signal channel to the multiplexers 13-4 to 13-7 to multiplex.

The wavelength converters 14a and 14b of this configuration include:
Each of the wavelength converters shown in FIGS. 11 to 13 can be used.
The optical matrix switches shown in FIG. 8 can be used as the optical matrix switches 15a and 15b of this configuration.
The transmitting and receiving unit shown in FIG. 9 can be used as the transmitting and receiving unit 17 of this configuration.

The routing processing unit 12a shown in this embodiment has a configuration in which each wavelength group path is wavelength-converted by the wavelength converter 14a and then input to the optical matrix switch 15a. The wavelength group paths that are switched by the matrix switch 15a and output may be wavelength-converted by the wavelength converter 14a. Also, the routing processing unit 12b shown in the present embodiment
Employs a configuration in which each wavelength path is wavelength-converted by the wavelength converter 14b and then input to the optical matrix switch 15b. Each wavelength path is switched by the optical matrix switch 15b, and the output wavelength path is converted by the wavelength converter. 14b may be configured to perform wavelength conversion.

As described above, as the network configuration is made into two layers, the configuration of the optical path cross-connect device is also made into two layers, so that control functions corresponding to each network are separated and independence is ensured. Aggregate traffic to the same destination transmitted from within the regional network. As a result, the wavelength group path utilization efficiency in the backbone network can be increased, and the throughput of the entire optical communication network can be increased.

In the case where the IP routers connected to the transmission / reception unit 17 are not provided in the same optical path cross-connect device 10 but are distributed and provided in another place in the same building, for example. In place of the transmission / reception unit 17, the same configuration as the backbone network corresponding unit 73 and the local network corresponding unit 74 is used, and a three-layer structure is adopted.

[0068]

As described above, the optical communication network and the optical path cross-connect device according to the present invention perform the routing processing in units of wavelength group paths obtained by grouping a plurality of wavelength paths, thereby increasing the routing processing capability. Can be raised significantly. As a result, the transmission cost per wavelength path can be significantly reduced.

FIG. 17 shows the relationship between the number of ports of the optical path cross-connect device and the wavelength path demand in the 4 × 9 grid optical communication network shown in FIG. In the conventional configuration, G = 1, and in the configuration of the present invention, G = 4, 8, and 16 (the number of wavelength paths constituting the wavelength group path). For example, in the case of 2,000 wavelength path demands, the present invention can reduce the number of ports of the optical path cross-connect device by about half by the routing processing of each wavelength group path, compared to the conventional routing processing of each wavelength path. it can.

When a wavelength group path is constituted by four wavelength paths, the number of ports of the optical path cross-connect device should ideally be reduced to 1/4 of the conventional configuration. However, in reality, when there is not enough wavelength path demand, the utilization of the wavelength group path decreases, and it is difficult to obtain the reduction effect to the ideal value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an optical path cross-connect device according to the present invention.

FIG. 2 is a view for explaining the difference between the conventional configuration of the optical path cross-connect device and the configuration of the present invention.

FIG. 3 is a diagram showing an example of wavelength arrangement of a wavelength group path.

FIG. 4 is a block diagram showing a configuration example of a duplexer 11 corresponding to the wavelength arrangement of FIG. 3 (3).

FIG. 5 is a block diagram showing a first embodiment of the optical communication network of the present invention.

FIG. 6 is a view for explaining the difference between the conventional configuration of the optical communication network and the configuration of the present invention.

FIG. 7 is a block diagram showing a configuration example of a wavelength division multiplexing transmission link 20.

8 is a block diagram showing a configuration example of an optical path cross-connect device 10 used at a point A in FIG.

FIG. 9 is a block diagram showing a configuration example of a transmission / reception unit 17;

FIG. 10 is a block diagram showing a configuration example of an optical matrix switch 15;

FIG. 11 is a block diagram showing a first configuration example of a wavelength converter 14.

FIG. 12 is a block diagram showing a second configuration example of the wavelength converter 14.

FIG. 13 is a block diagram showing a third configuration example of the wavelength converter 14.

FIG. 14 is a diagram showing a configuration example of light dispersion media 53 and 56 and second-order optical nonlinear media 54 and 55.

FIG. 15 is a block diagram showing a second embodiment of the optical communication network according to the present invention.

16 is a block diagram showing a configuration example of an optical path cross-connect device 10 used at a point B in FIG.

FIG. 17 is a diagram illustrating a relationship between the number of ports of an optical path cross-connect device and a wavelength path demand.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 optical path cross connect device 11 demultiplexer 12 routing processing unit 13 multiplexer 14 wavelength converter 15 optical matrix switch 16 optical fiber 17 transceiver unit 18 controller 20 wavelength multiplexing transmission link 21 core expanding fiber 22 dispersion compensating fiber 23 optical fiber Amplifier 31 Electro-optical converter (E / O) 32, 36 Crossbar switch 33 Multiplexer 34 Demultiplexer 35 Opto-electric converter (O / E) 40 Reflector switch 41 Demultiplexer 42 Tunable laser light source 43, 45 Wavelength conversion element 44 multiplexer 46 semiconductor optical amplifier 47 optical coupler 51 WDM coupler 52, 57 optical multiplexer / demultiplexer 53, 56 light dispersion medium 54, 55 second-order optical nonlinear medium 60 LiNbO ₃ substrate 61, 62 non-pseudo phase matching LiNbO ₃ waveguide 63, 64 quasi-phase matched LiNbO ₃ waveguide 71 Stem network 72 local networks 73 core network corresponding portion 74 local networks corresponding portion 111 optical star coupler 112, 114 AWG 113 optical gate switch group

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Atsushi Takada 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5K002 BA05 BA06 CA02 DA02 DA13 5K069 AA13 BA09 CB10 DB33 EA24 EA25 EA26 FA26

Claims (16)

[Claims] 1. A wavelength division multiplex transmission link connecting a plurality of optical path cross-connect devices and a wavelength multiplex transmission link connecting the plurality of optical path cross connect devices, wherein a wavelength path transmitted through the wavelength multiplex transmission link is routed by the optical path cross connect device based on the wavelength. In the optical communication network, the optical path cross-connect device converts the wavelength paths of the wavelength multiplexing transmission link into N (N is an integer of 2 or more) wavelength group paths by G (G is an integer of 2 or more). An optical communication network, wherein the optical communication network is configured to divide the wavelength group path and perform a routing process for each wavelength group path. 2. The optical communication network according to claim 1, wherein
To z (z is an integer of 2 or more), and the number of wavelength group paths N1, N2,
, Nz and the number of wavelength paths G1, G2,..., Gz constituting each wavelength group path, the number N0 of wavelength group paths routed between the respective sub-regions, and the wavelength paths constituting the wavelength group path Are set independently of each other (N0 to Nz are integers of 2 or more, and G0 to Gz are integers of 2 or more). 3. The optical communication network according to claim 1, wherein each of the G (G0 to Gz) wavelength paths constituting the N (N0 to Nz) wavelength group paths has a wavelength of λ1. , 1 to λ1, G,
When λ2,1 to λ2, G, ..., λN, 1 to λN, G,
[λ1,1 to λ1, G], [λ2,1 to λ2, G],…, [λN, 1 to
λN, G] are continuously arranged on the wavelength axis. 4. The optical communication network according to claim 1, wherein each of the G (G0 to Gz) wavelength paths constituting the N (N0 to Nz) wavelength group paths has a wavelength of λ1. , 1 to λ1, G,
When λ2,1 to λ2, G, ..., λN, 1 to λN, G,
[λ1,1 to λ1, G], [λ2,1 to λ2, G],…, [λN, 1 to
λN, G] are arranged at equal wavelength intervals on the wavelength axis, and [λ1,1 to λN, 1], [λ1,2 to λN, 2],.
An optical communication network wherein [λ1, G to λN, G] are continuously arranged on the wavelength axis. 5. The optical communication network according to claim 1, wherein each of G (G0 to Gz) wavelength paths constituting said N (N0 to Nz) wavelength group paths is a communication demand. 1 to G (1 to G0, 1 to G1, 1 to G2, ..., 1 to Gz), respectively.
An optical communication network variably set within the range of a book. 6. The optical communication network according to claim 5, wherein each of the N (N0 to Nz) wavelength group paths includes 1 to G (1 to G0, 1 to G1, 1 to G2,...). 1 to Gz) The wavelengths of the wavelength paths are defined as λ1,1 to λ1, g1, λ2,1 to λ2, g2,
.., ΛN, 1 to λN, gn (g1 to gn are 1 to G
(An integer of 1 to G0,1 to G1,1 to G2, ..., 1 to Gz),
[λ1,1 to λ1, g1], [λ2,1 to λ2, g2], ..., [λN,
1 to λN, gn] are continuously arranged on the wavelength axis. 7. The optical communication network according to claim 1, wherein a monitoring unit of the optical signal transmitted through the wavelength division multiplexing transmission link is a wavelength group path which is a unit of the routing process. Characteristic optical communication network. 8. An optical path cross-connect device for inputting a wavelength path transmitted through a plurality of wavelength division multiplex transmission links, performing routing processing based on the wavelengths, and outputting the result to a corresponding wavelength division transmission link. A plurality of duplexers for inputting the wavelength paths of the transmission link and separating each of the G (G is an integer of 2 or more) into N (N is an integer of 2 or more) wavelength group paths; A light processing apparatus, comprising: a routing processing means for performing routing processing in units of: a plurality of multiplexers for multiplexing for each wavelength multiplexing transmission link that outputs each wavelength group path routed by the routing processing means. Path cross connect device. 9. The optical path cross-connect device according to claim 8, comprising a plurality of optical path cross-connect processing sections each including the plurality of demultiplexers, the routing processing means, and the plurality of multiplexers. Hierarchical, one demultiplexer and one multiplexer are sequentially connected between layers, and the wavelength division multiplexing transmission link is connected to the remaining demultiplexers and multiplexers for each layer. Characteristic optical path cross-connect device. 10. The optical path cross-connect device according to claim 9, wherein the number of wavelength-division multiplexing transmission links, the number of wavelength group paths, and the wavelength paths forming the wavelength group paths connected to the optical path cross-connect processing units of the respective layers. Are configured to be set independently of each other. 11. The optical path cross-connect device according to claim 8, wherein the routing processing unit performs wavelength conversion on a plurality of wavelength paths constituting the wavelength group path, and a wavelength converter. An optical matrix switch for routing the wavelength group path. 12. The optical path cross-connect device according to claim 11, wherein the wavelength converter is an optical parametric wavelength converter that collectively converts wavelengths of a plurality of wavelength paths constituting the wavelength group path. Characteristic optical path cross-connect device. 13. The optical path cross-connect according to claim 12, wherein the optical parametric wavelength converter includes an optical filter for removing an input wavelength path and noise light. apparatus. 14. The optical path cross-connect device according to claim 12, wherein the optical parametric wavelength converter has two output ports of a two-input two-output first optical multiplexer / demultiplexer and two-input two-output. A nonlinear Mach-Zehnder interferometer having an optical dispersion medium and a second-order optical nonlinear medium inserted into two optical paths respectively connecting two input ports of the second optical multiplexer / demultiplexer; A first secondary optical nonlinear medium is inserted after the first optical dispersion medium in one optical path between the optical coupler and the second optical multiplexer / demultiplexer, and a second optical nonlinear medium is inserted in the other optical path. The second optical dispersion medium is inserted next to the second-order optical nonlinear medium, and one of the input ports of the first optical multiplexer / demultiplexer is used to generate signal light and wavelength-converted light constituting the wavelength group path. Multiplexed light of the pumping light to be input to one of the second optical multiplexer / demultiplexers. An optical path cross-connect device, which outputs a signal light and a pump light from an output port of the optical path and outputs a wavelength group path obtained by wavelength conversion with respect to a wavelength group path input from the other output port. 15. The optical path cross-connect device according to claim 8, wherein the splitter and the multiplexer have an arrayed waveguide grating type multiplexer / demultiplexer having a periodic transmission wavelength characteristic. An optical path cross-connect device, which is a device (AWG). 16. The optical path cross-connect device according to claim 8, wherein said demultiplexer and said multiplexer are arrayed waveguide grating type multiplexer / demultiplexer having periodic transmission wavelength characteristics. An optical path cross-connect device comprising a two-stage configuration (AWG) and an optical gate switch for selectively transmitting or blocking each wavelength path split between them.