JP2004297558A - Optical wavelength division multiplexing transmission network apparatus, wavelength router and transmitter-receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical wavelength division multiplexing network apparatus capable of reducing a line operation and management cost and an apparatus cost by decreasing the consumed amount of optical fibers tying a wavelength router and each transmitter-receiver. <P>SOLUTION: The wavelength router is provided with N-sets of first optical multiplexing circuits 215 each connecting prescribed input and output ports of a wavelength routing circuit 209a to another port and a second optical multiplexing circuit 214 for connecting an input port of an optical demultiplexer 207 and an output port of an optical multiplexer 208 to another port, and each port of the wavelength router 209 and each of the other ports of the transmitter-receivers 201 to 204 are interconnected by one optical fiber (210 to 213). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical wavelength division multiplexing transmission network device, a wavelength router, and a transmission / reception device for transmitting a plurality of optical signals that have been subjected to optical wavelength division multiplexing between a plurality of transmission / reception devices.
[0002]
[Prior art]
An optical wavelength division multiplexing (WDM) transmission system allocates a plurality of optical signals to different optical frequencies and transmits them through one optical fiber. This optical wavelength division multiplexing transmission system not only greatly increases the transmission capacity, but also enables wavelength addressing for assigning destination information of a signal to a wavelength itself. Further, there is a star-type optical wavelength division multiplexing transmission network system in which N transmission / reception devices are arranged and connected mainly to a wavelength router having a demultiplexing characteristic of a periodic input / output relationship. In this optical wavelength division multiplexing transmission system, it is possible to realize a network device capable of independently and fully mesh-connecting N × N signal paths for interconnecting transmission / reception devices only by using N-wavelength optical signals (for example, And Patent Document 1).
[0003]
FIG. 4 is a schematic diagram showing such a conventional optical wavelength division multiplexing transmission network device. In the figure, reference numerals 401 to 407 denote transmission / reception devices for mutually transmitting and receiving wavelength multiplexed signals λ1 to λN, and reference numeral 408 denotes an N × N wavelength having N input / output ports and having a demultiplexing characteristic of a periodic input / output relationship. It is a router. As the wavelength router 408, for example, an array waveguide diffraction grating type multiplexing / demultiplexing circuit (AWG) is used. Here, the wavelength router 408 and each of the transmission / reception devices 401 to 407 are connected to each other by two optical fibers, one upstream and one downstream.
[0004]
In such a conventional optical wavelength division multiplexing network device, for example, an optical signal of a predetermined wavelength transmitted from one transmitting / receiving device 401 via one optical fiber is guided to an input port of a wavelength router 408. The wavelength router 408 switches the optical signal according to the wavelength, and transmits the optical signal from the output port to, for example, the transmitting / receiving device 402. On the other hand, the return signal transmitted from the transmission / reception device 402 is transmitted to the transmission / reception device 401 via the wavelength router 408 and the other optical fiber. An optical signal of another wavelength transmitted from the transmitting / receiving device 401 is automatically distributed to, for example, the other transmitting / receiving devices 403, 405, and the like.
[0005]
FIG. 5 is a specific block diagram of the optical wavelength division multiplexing transmission network device shown in FIG. In the figure, 501 to 504 are transmission / reception devices, 505 is a reception circuit for receiving wavelength multiplexed signals λ1 to λN, 506 is a transmission circuit for transmitting wavelength multiplexed signals λ1 to λN, and 507 is wavelength multiplexed on one optical fiber. An optical demultiplexer 508 for demultiplexing the wavelength-division multiplexed signal is an optical multiplexer for multiplexing a plurality of optical signals having different wavelengths from the transmission circuit 506 into one optical fiber.
[0006]
Reference numeral 509 denotes a wavelength router (AWG), and reference numerals 510 to 513 denote optical fibers for optically connecting the transmission / reception devices 501 to 504 and the input / output ports of the wavelength router 509. The configuration of the transmission / reception devices 502 to 504 is the same as that of the transmission / reception device 501. As described above, each of the transmission / reception devices 501 to 504 and the wavelength router 509 are connected by two optical fibers 510 to 513 in the upstream and downstream directions.
[0007]
In this network device, for example, optical signals of different wavelengths output from the transmission circuit 506 of the transmission / reception device 501 are multiplexed by the optical multiplexer 508 and transmitted as a wavelength multiplexed signal to the wavelength router 509 through one optical fiber 510. I do. On the other hand, a wavelength multiplexed signal transmitted from the other transmitting / receiving device 504 via the wavelength router 509 is transmitted to the transmitting / receiving device 501 through another optical fiber 510. In the transmitting / receiving device 501, the wavelength division multiplexed signal is demultiplexed by the optical demultiplexer 507, and the signal of each wavelength is received by the receiving circuit 505.
[0008]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-201112
[Problems to be solved by the invention]
However, in such a conventional optical wavelength division multiplexing transmission network device, since the wavelength router and the transmitting / receiving node are connected using two optical fibers, ie, upstream and downstream, the number of nodes (the number of transmitting / receiving devices) M (M (2 is an integer not less than 2 and not more than N), it is necessary to prepare 2M optical fibers, and there is a problem that the usage and management costs of the optical fibers increase the operation cost of the network.
[0010]
In addition, in order to manage the optical wavelength, it is necessary to provide a semiconductor laser, a wavelength router, an optical multiplexer, and an optical demultiplexer with a temperature sensor and a temperature adjusting mechanism for controlling the element temperature, thereby increasing the apparatus cost. There was a problem that it would.
[0011]
The present invention has been made in view of such a conventional problem, and an object of the present invention is to exchange optical signals even when a wavelength router and a plurality of transmitting / receiving apparatuses are connected by one optical fiber each. It is an object of the present invention to provide an optical wavelength division multiplexing network device capable of reducing the line operation, management cost and device cost.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an optical wavelength division multiplexing transmission network device according to the present invention comprises a wavelength router having N (N is a plurality) connection ports, a predetermined connection port of the wavelength router, and an optical network. A star-type optical wavelength division multiplexing transmission network device comprising M (M is an integer of 2 or more and N or less) N transmission / reception devices, wherein the wavelength router has N connection ports. A wavelength routing circuit having three input ports and N output ports; N first optical convergence circuits connecting predetermined input ports and output ports of the wavelength routing circuit to another port; An optical splitter that splits the wavelength-multiplexed optical signal input to its own input port into M wavelengths, and outputs the split optical signal from M output ports. Or an optical splitter A receiving circuit for receiving the M wavelength optical signal from the M input ports, a transmitting circuit for transmitting the M wavelength optical signal from the M output ports, and the M output from the M output ports of the transmitting circuit. An optical multiplexer for multiplexing an optical signal having a wavelength and transmitting the multiplexed optical signal from its own output port as a wavelength multiplexed signal, and an input port of the optical demultiplexer and an output port of the optical multiplexer to another port. A second optical multiplexing circuit to be connected, wherein the wavelength router, the optical demultiplexer, and the optical multiplexer have a transmission band equal to or larger than a wavelength shift width due to a temperature change, and set a center wavelength of the transmission band to ITU- The wavelength router is shifted to a longer wavelength side than the T grid wavelength, and the wavelength router is connected to the other port in each of the transmitting and receiving apparatuses by one optical fiber.
[0013]
Thereby, in the first optical multiplexing circuit, the multiplexed wavelength multiplexed signal from the transmission / reception device is taken into the wavelength router via one optical fiber, and the wavelength multiplexed signal from the wavelength router is transmitted to the one optical fiber. Can be transmitted to the transmission / reception device via the. Further, in the second optical multiplexing circuit, the wavelength multiplexed signal from the wavelength router is taken into the optical demultiplexer via the one optical fiber, and the wavelength multiplexed signal transmitted from the optical multiplexer is transmitted to the one optical multiplexer. It can be sent to a wavelength router via a fiber. Therefore, the number of optical fibers used can be halved from the conventional two to one. In addition, by shifting the center wavelength of the transmission band to the longer wavelength side, an inexpensive optical wavelength division multiplexing transmission network system that does not require a temperature controller, a wavelength stabilization controller, or the like can be constructed.
[0014]
An optical wavelength division multiplexing transmission network device according to a second aspect of the present invention is characterized in that the first optical multiplexing circuit comprises an optical circulator or an optical coupler. As a result, transmission of optical signals between a plurality of transmitting / receiving apparatuses and the wavelength router can be realized inexpensively with a small number of optical fibers while keeping the loss low.
[0015]
An optical wavelength division multiplexing transmission network device according to a third aspect of the present invention is characterized in that the second optical multiplexing circuit comprises an optical circulator or an optical coupler. As a result, transmission of optical signals between a plurality of transmitting / receiving apparatuses and the wavelength router can be realized inexpensively with a small number of optical fibers while keeping the loss low.
[0016]
The optical wavelength division multiplexing transmission network device according to the invention of claim 4 is characterized in that the center wavelength of the transmission band of the optical multiplexer and the optical demultiplexer is shifted in advance to the longer wavelength side. As a result, it is possible to cover the temperature fluctuation of the transmission circuit and the like and the wavelength shift generated under other conditions, and maintain the desired wavelength routing function.
[0017]
A wavelength router according to a fifth aspect of the present invention is a wavelength router having a connection port optically connected to a plurality of transmission / reception devices in an optical wavelength division multiplexing transmission network device, wherein a transmission band is caused by temperature fluctuation. The oscillation wavelength shift width of the semiconductor laser is set to be greater than or equal to the wavelength, and the center wavelength of the transmission band is shifted to a longer wavelength side than the ITU-T grid wavelength. This makes it possible to cover the wavelength shift of the oscillation wavelength due to the temperature change of the transmission circuit, and thus to stably maintain the desired wavelength routing function.
[0018]
A wavelength router according to a sixth aspect of the present invention is a wavelength router having a connection port optically connected to a plurality of transmission / reception devices in an optical wavelength division multiplexing transmission network device, wherein N is the connection port. A wavelength routing circuit having three input ports and N output ports, and N optical converging circuits connecting predetermined input ports and output ports of the wavelength routing circuit to another port. It is characterized by having. Accordingly, only one optical multiplexing circuit is added for each wavelength routing circuit having N input ports and output ports, and transmission and reception of a wavelength multiplexed signal to and from each transmitting / receiving apparatus through one optical fiber. Can be realized at low cost.
[0019]
Further, the transmitting / receiving apparatus according to the invention of claim 7 demultiplexes the wavelength-multiplexed optical signal input to its own input port into M wavelengths, and outputs the demultiplexed optical signal from M output ports. An optical demultiplexer, a receiving circuit for receiving an M-wavelength optical signal from the optical demultiplexer to M input ports, a transmitting circuit for transmitting an M-wavelength optical signal from the M output ports, and a transmitting circuit An optical multiplexer that multiplexes the optical signals of M wavelengths output from the M output ports of the optical multiplexer and sends out the wavelength-multiplexed signal from its own output port; an input port of the optical demultiplexer; And an optical converging circuit for connecting the output port to another port. As a result, the transmission / reception device can use a single optical fiber to transmit / receive a wavelength multiplexed signal to / from a wavelength router through a receiver and a transmitter at low cost.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0021]
FIG. 1 is a schematic diagram showing an optical wavelength division multiplexing transmission network device of the present invention. In the figure, reference numerals 101 to 107 denote transmission / reception devices for transmitting and receiving wavelength multiplexed signals λ1 to λN, and 108 denotes an N × N wavelength router having N input / output ports and having a demultiplexing characteristic of a periodic input / output relationship. is there. In this embodiment, an array waveguide diffraction grating type demultiplexer (AWG) is used as the wavelength router 108. Here, FIG. 1 is different from the conventional example shown in FIG. 4 in that the transmission / reception devices 101 to 107 and the wavelength router 108 are connected by one optical fiber.
[0022]
FIG. 2 is a block diagram specifically showing an embodiment of the optical wavelength division multiplexing transmission network device according to the present invention. In the figure, reference numerals 201 to 204 denote transmission / reception devices, 205 denotes a reception circuit that receives wavelength multiplexed signals λ1 to λN, and 206 denotes a transmission circuit that transmits wavelength multiplexed signals λ1 to λN.
[0023]
Reference numeral 208 denotes an optical multiplexer for multiplexing a plurality of optical signals having different wavelengths into one optical fiber, and reference numeral 207 denotes an optical multiplexer for demultiplexing a wavelength-division multiplexed signal from one optical fiber. An optical demultiplexer, 209 is a wavelength router interconnecting the transmission / reception devices 201 to 204, 209a is a wavelength routing circuit in the wavelength router 209, and 210 to 213 optically connect the transmission / reception devices 201 to 204 and the wavelength router 209. The optical fibers 214 and 215 are three-port optical circulators as optical converging circuits. In this embodiment, as the wavelength router 209, for example, an N × N array waveguide diffraction grating type multiplexing / demultiplexing circuit (AWG) is used. The configuration of the transmitting / receiving apparatuses 202 to 204 is the same as that of the transmitting / receiving apparatus 201.
[0024]
Here, in each of the transmission / reception devices 201 to 204, the input port of the optical demultiplexer 507, the output port of the optical multiplexer 508, and the optical fiber are connected to three ports of the optical circulator 214, and the output from the optical multiplexer 508 is optical. The optical fiber is connected so as to be input to the fiber and the output from the optical fiber is input to the optical demultiplexer 507. Further, in the wavelength router 209, each input port and output port of the wavelength routing circuit 209a and one optical fiber are input to three ports of each optical circulator 215, and the output from the optical fiber is input to the wavelength routing circuit 209a. The connection is made such that the output from the wavelength routing circuit 209a is input to the optical fiber.
[0025]
In this embodiment, one optical fiber connects each of the transmitting / receiving apparatuses 201 to 204 and the wavelength router 209. Accordingly, the amount of optical fiber used can be greatly reduced, and an optical wavelength division multiplex transmission device and an optical communication service can be provided at low cost.
[0026]
In such an optical wavelength division multiplexing transmission network device, for example, optical signals of different wavelengths output from the transmission circuit 206 of the transmission / reception device 201 are multiplexed by the optical multiplexer 208, and are converted into a wavelength multiplexed signal by the optical circulator 214 and one of the The signal is transmitted to the wavelength router 209 through the optical fiber 210. The wavelength multiplexed signal transmitted to the wavelength router 209 through the single optical fiber 210 is transmitted to, for example, the first input port of the wavelength routing circuit 209a via the optical circulator 215, and is output to each output port for each wavelength. Is done.
[0027]
On the other hand, the signal is transmitted from another transmission / reception device to the wavelength router 209, is output to the first output port of the wavelength routing circuit 209a according to the wavelength, and the wavelength-multiplexed optical signal is shared by the optical circulator 215 during transmission. Is transmitted to the transmitting / receiving apparatus 201 through the one optical fiber 210. In the transmitting / receiving device 201, the wavelength multiplexed signal is split by the optical splitter 207 through the optical circulator 214, and the signal of each wavelength is received by the receiving circuit 205.
[0028]
FIG. 3 is an explanatory diagram for explaining the operation of the present embodiment. In general, a semiconductor laser for CWDM without a temperature control mechanism is manufactured and inspected with a certain wavelength variation with respect to an ITU-T grid wavelength at an interval of 20 nm before being shipped. In FIG. 3, the wavelength variation is ± 2 nm. However, in an actual use state, a current of several tens to several hundreds of mA flows through a driver circuit or a semiconductor laser in order to incorporate these semiconductor lasers into a device together with a drive circuit and to input a signal to make the semiconductor laser active.
[0029]
As a result, the element temperature rises by about 10 to 15 ° C., and the oscillation wavelength of the semiconductor laser shifts to the longer wavelength side by 1 to 1.5 nm. Furthermore, when the temperature of the installation environment of the apparatus rises to 50 ° C., the element temperature rises to about 65 ° C., and the oscillation wavelength of the laser may shift up to 6 nm longer wavelength side in consideration of the dispersion of the initial wavelength. Understand. Similarly, when the installation environment temperature of the device drops to about 0 ° C., the oscillation wavelength of the semiconductor laser shifts to a shorter wavelength side by a maximum of 3 nm.
[0030]
Therefore, as shown in FIG. 3, the center wavelength of the transmission band of the optical demultiplexer 207, the optical multiplexer 208, and the wavelength router 209 is shifted by 1 nm to the longer wavelength side, and the transmission bandwidth is set to 9 nm or more. Can cover shifts. As a result, even if the ambient temperature of the installation place of the device changes between 0 and 50 ° C. and the oscillation wavelength of the semiconductor laser shifts, the wavelength router 109 can maintain the wavelength routing function. In this embodiment, the optical circulator is used as the optical convergence circuit, but the same effect can be obtained by using an optical coupler.
[0031]
As a result, there is no need to prepare a temperature sensor or a temperature control element for controlling the temperature of the semiconductor laser, which has been conventionally performed, and the transmission bandwidth can be suppressed to the minimum while allowing the temperature fluctuation, and the apparatus cost is reduced. Reduction can be achieved.
[0032]
【The invention's effect】
As described above, according to the present invention, N first optical multiplexing circuits for connecting a predetermined input port and output port of a wavelength routing circuit to another port, and an optical demultiplexer of a transmitting / receiving apparatus A second optical multiplexing circuit for connecting the input port of the optical demultiplexer and the output port of the optical demultiplexer to another port is provided. A wavelength multiplexed signal can be taken into a wavelength router via a single optical fiber common to upstream and downstream, and a wavelength multiplexed signal from the wavelength router can be sent to a transmitting / receiving apparatus via the single optical fiber. On the other hand, in the second optical multiplexing circuit, the wavelength multiplexed signal from the wavelength router is taken into the optical demultiplexer via the one optical fiber, and the wavelength multiplexed signal transmitted from the optical multiplexer is transmitted to the one optical multiplexer. It can be sent to a wavelength router via a fiber. Therefore, the number of used optical fibers (number of wires) connecting the wavelength router and each transmitting / receiving device can be reduced from the conventional two to one, and the device cost can be reduced. Further, by shifting the center wavelength of the transmission band of the wavelength router, the optical demultiplexer, and the optical multiplexer to the longer wavelength side, the temperature conventionally used for preventing the oscillation wavelength from shifting due to the temperature change of the semiconductor laser. A controller and a wavelength stabilization controller can be omitted, and as a result, an inexpensive optical wavelength division multiplexing transmission network system can be constructed.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically illustrating an optical wavelength division multiplexing transmission network device according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a specific example of an optical wavelength division multiplexing transmission network device according to an embodiment of the present invention. FIG. 3 is an operation explanatory diagram showing the operation of the embodiment of the present invention. FIG. 4 is a block diagram schematically showing a conventional wavelength division multiplex transmission network device. FIG. 5 is a block diagram showing the wavelength division multiplex transmission network device of FIG. Figure [Explanation of symbols]
101 to 107: transmitting / receiving apparatus, 108: wavelength router, 201 to 204: transmitting / receiving circuit, 205: receiving circuit, 206: transmitting circuit, 207: optical demultiplexer, 208: optical multiplexer, 209: wavelength router, 209a: wavelength Routing circuit, 210-213: optical fiber, 214, 215: circulator (optical converging circuit).

Claims (7)

The wavelength router is provided with N (N is a plurality) connection ports, and M (M is an integer of 2 or more and N or less) optically connected to a predetermined connection port of the wavelength router. Star-type optical wavelength division multiplexing transmission network device,
The wavelength router,
A wavelength routing circuit having N input ports and N output ports serving as the connection ports;
N first optical convergence circuits for connecting predetermined input ports and output ports of the wavelength routing circuit to another port, and
The transmitting and receiving device,
An optical demultiplexer that demultiplexes the wavelength-multiplexed optical signal input to its own input port into M wavelengths and outputs the demultiplexed optical signal from the M output ports;
A receiving circuit that receives an M-wavelength optical signal from the optical demultiplexer at M input ports;
A transmitting circuit for transmitting an M wavelength optical signal from the M output ports;
An optical multiplexer that multiplexes the M wavelength optical signals output from the M output ports of the transmission circuit and sends out the wavelength multiplexed signal from its own output port;
A second optical multiplexing circuit that connects an input port of the optical demultiplexer and an output port of the optical multiplexer to another one port,
The wavelength router, optical demultiplexer, the transmission band of the optical multiplexer is greater than or equal to the wavelength shift width due to temperature fluctuation, and the center wavelength of the transmission band is shifted to a longer wavelength side than the ITU-T grid wavelength,
An optical wavelength division multiplexing transmission network device, wherein the wavelength router and the other port in each of the transmission / reception devices are connected to each other by one optical fiber. 2. The optical wavelength division multiplexing transmission network device according to claim 1, wherein the first optical combining circuit comprises an optical circulator or an optical coupler. 2. The optical wavelength division multiplexing transmission network device according to claim 1, wherein the second optical combining circuit comprises a circulator or an optical coupler. 4. The optical wavelength division multiplexing transmission network device according to claim 1, wherein a center wavelength of a transmission band of the optical multiplexer / demultiplexer is shifted in advance to a longer wavelength side. A wavelength router having a connection port optically connected to a plurality of transmission / reception devices in an optical wavelength division multiplexing transmission network device,
A wavelength router wherein a transmission band is set to be equal to or more than an oscillation wavelength shift width of a semiconductor laser due to a temperature change, and a center wavelength of the transmission band is shifted to a longer wavelength side than an ITU-T grid wavelength. A wavelength router having a connection port optically connected to a plurality of transmission / reception devices in an optical wavelength division multiplexing transmission network device,
A wavelength routing circuit having N input ports and N output ports serving as the connection ports;
What is claimed is: 1. A wavelength router, comprising: N optical coupling circuits for connecting a predetermined input port and an output port of a wavelength routing circuit to another port. An optical demultiplexer that demultiplexes the wavelength-multiplexed optical signal input to its own input port into M wavelengths and outputs the demultiplexed optical signal from the M output ports;
A receiving circuit that receives an M-wavelength optical signal from the optical demultiplexer at M input ports;
A transmitting circuit for transmitting an M wavelength optical signal from the M output ports;
An optical multiplexer that multiplexes the M wavelength optical signals output from the M output ports of the transmission circuit and sends out the wavelength multiplexed signal from its own output port;
A transmission / reception device comprising: an optical multiplexing circuit that connects an input port of the optical demultiplexer and an output port of the optical multiplexer to another port.

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