JP3292843B2 - Optical wavelength division multiplexing transmission network equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a full mesh optical wavelength division multiplexing transmission network apparatus for transmitting a plurality of optical signals multiplexed by optical wavelength between a plurality of transmitting / receiving apparatuses.

[0002]

2. Description of the Related Art Optical wavelength division multiplexing (WDM) in which a plurality of optical signals are allocated to different optical frequencies and transmitted through one optical fiber.
The transmission system can not only greatly increase the capacity of the transmission path, but also perform wavelength addressing that can assign destination information of a signal to the wavelength itself. Further, a star-type WDM system in which an arrayed waveguide diffraction grating type multiplexing / demultiplexing circuit having a demultiplexing characteristic of a periodic input / output relationship is connected at the center so as to connect N transmitting / receiving apparatuses, has N wavelengths. It is possible to realize a full mesh WDM transmission network device capable of independently connecting N × N signal paths for interconnecting devices simply by using optical signals.

FIG. 4 is a schematic diagram showing a conventional full mesh WDM transmission network device. In the figure, reference numerals 1 to 7 denote transmission / reception devices for transmitting and receiving WDM signals (λ _{1 to} λ _n ), and reference numeral 8 denotes N
N × N array waveguide diffraction grating type multiplexing / demultiplexing circuit (AW
G).

FIG. 5 is a diagram for explaining a schematic configuration of the full mesh WDM transmission network device shown in FIG. 4. In FIG. 5, reference numerals 9 to 12 denote transmission / reception devices, and reference numeral 13 denotes a WDM signal (λ _{1 to} λ).
_n ), a transmitter 14 for transmitting WDM signals (λ _{1 to} λ _n ), 15 a demultiplexer for demultiplexing a WDM signal wavelength-multiplexed on one fiber, and 16 a demultiplexer. A multiplexer for multiplexing a plurality of optical signals having different wavelengths from the transmitting device 14 into one optical fiber, 17 is an N × N array waveguide diffraction grating type multiplexer / demultiplexer (AWG), 18 to 21 Is an optical fiber that optically connects the transmission / reception devices 9 to 12 and the input / output port of the AWG 17. In addition, the transmitting and receiving apparatuses 10-1
The configuration of 2 is the same as that of the transmitting / receiving device 9.

FIG. 6 is a diagram showing the demultiplexing characteristics of the periodic input / output relationship of the AWG and the connection relationship between each transmitting / receiving device and the AWG port in the conventional full mesh WDM transmission network device when N = 8. It is. AWG having a demultiplexing characteristic of a periodic input / output relationship is disclosed in Japanese Patent Application No. Hei 10-210.
679 etc. Here, the case of 8 × 8 AWG is shown for simplicity. 8 × 8 = 64 types of paths are set between the 8-input and 8-output AWG ports, but 64 types of paths with the minimum number of wavelengths of 8 are provided due to the reciprocity of the demultiplexing characteristic as shown in the figure. Can be set independently. By connecting the input / output port of the AWG to each transmitting / receiving device, signals can be transmitted independently on all paths that can be set among the eight transmitting / receiving devices. Further, since a specific wavelength λ _i is assigned to each path, a wavelength addressing function of automatically transmitting a signal to a target receiving device can be realized if the transmitting device selects a wavelength corresponding to the receiving device.

FIG. 7 is a diagram for explaining wavelength addressing. In FIG.
Is 8 × 8 AWG. AWG demultiplexing characteristics and AWG
The connection relationship between the port and the transmission / reception device is as described in FIG. The optical signal of λ ₇ transmitted from the transmitting device (1) 22 is guided to the input port 1 of the AWG 30 and A
The signal is switched in the WG 30 and sent from the output port 2 to the transmission / reception device (2) 23. Similarly, the return signal λ ₇ transmitted from the transmission / reception device (2) 23 is transmitted to the transmission / reception device (1) 22 via the AWG 30. Also, the transmitting / receiving device (1) 22
The optical signals λ ₂ and λ ₈ transmitted from the
(5) Automatically distributed to 26 and transmitting / receiving device (3) 24.

[0007]

However, in such a conventional full mesh WDM transmission network device, since the signal destination corresponds to the wavelength on a one-to-one basis, a transmission device of a certain wavelength or a semiconductor which is a light source is used. When the laser breaks down, there arises a problem that a signal cannot be sent to the corresponding receiving device. A similar failure occurs when a receiver of a specific wavelength breaks down. This has been a serious problem in the operation and management of the system. Further, it has not been possible to temporarily allocate a plurality of wavelengths between all the specific transmitting and receiving apparatuses to increase the transmission capacity.

The present invention has been made in view of such a problem, and an object of the present invention is to cope with a failure of a transmission or reception device of a specific wavelength, and to reduce a transmission capacity between specific transmission and reception devices as necessary. An object of the present invention is to provide a full-mesh optical wavelength division multiplexing transmission network device that can be expanded.

[0009]

In order to achieve the above object, the present invention provides an array waveguide diffraction grating type multiplexing / demultiplexing circuit having N (N is plural) input ports and N output ports. And an optical wavelength division multiplexing transmission network device having a star network configuration composed of N transmission / reception devices optically connected to predetermined input / output ports of the array waveguide diffraction grating type multiplexing / demultiplexing circuit. The array waveguide diffraction grating type multiplexing / demultiplexing circuit has a demultiplexing characteristic of a periodic input / output relationship, and the transmission / reception device includes a predetermined one of the array waveguide diffraction grating type multiplexing / demultiplexing circuit. The optical signal input from the output port is split into N wavelengths, and the split optical signal is
A demultiplexer for outputting optical signals of N wavelengths, a transmitting circuit for transmitting optical signals of N wavelengths from N output ports, a receiving circuit for receiving optical signals of N wavelengths to N output ports,
N wavelength optical signals input from the input ports are multiplexed, and a predetermined one of the arrayed waveguide diffraction grating type multiplexing / demultiplexing circuit is combined.
A multiplexing circuit that outputs to an input port of the book, a state in which an output port of the demultiplexing circuit is connected to an input port of the receiving circuit, and an output port of the transmitting circuit is connected to an input port of the multiplexing circuit. N for switching the output port of the transmitting circuit to the input port of the receiving circuit and the output port of the demultiplexing circuit to the input port of the multiplexing circuit for each wavelength. And a two-input / two-output optical path changeover switch. According to the present invention, an optical signal transmitted from a transmission device and switched by a wavelength in an arrayed waveguide grating type multiplexer / demultiplexer and sent to a specific reception device is a two-input two-output optical path changeover switch in the transmission / reception device. The signal is returned to the arrayed-waveguide grating type multiplexing / demultiplexing circuit, and is switched again by the wavelength in the arrayed-waveguide grating type multiplexing / demultiplexing circuit, and delivered to a different receiver. By repeating this operation, the signal is delivered to the intended receiving device. Therefore, even if the transmitting device or the receiving device of a certain wavelength breaks down, the signal can be transmitted via such a bypass. Similarly, since a plurality of signal paths can be temporarily realized between specific transmission / reception devices, a temporary increase in transmission capacity can be realized. In an optical connection between a predetermined input / output port of the arrayed waveguide grating type multiplexing / demultiplexing circuit and a transmitting / receiving device, the i-th (i is 1 or more N It can be easily configured by connecting the transmitting device and the receiving device in which the (integer) th input port and the (N−i + 1) th output port are paired with each other using an optical fiber.
Further, the N 2-input 2-output optical path changeover switches disposed in the transmission / reception device can be configured by using a thermo-optic switch utilizing the thermo-optic effect of a quartz-based planar lightwave circuit.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of an embodiment of the present invention, and shows a schematic configuration of an optical wavelength division multiplexing transmission network device. In the figure, reference numerals 31 to 34 denote transmission / reception devices, 35 denotes a transmission device for transmitting WDM signals (λ _{1 to} λ _n )
36 is a receiving device for receiving WDM signals (λ _{1 to} λ _n );
Is a multiplexer for multiplexing a plurality of optical signals having different wavelengths into one optical fiber, 38 is a demultiplexer for demultiplexing a WDM signal wavelength-multiplexed on one fiber, and 39 is a transmitter. N 2 inputs 2 for switching the optical signal from the device 35 and the optical signal from the demultiplexer 38 to the receiving device 36 and the multiplexer 37
An output optical path changeover switch 40 is an N × N arrayed waveguide diffraction grating type multiplexing / demultiplexing circuit (AWG), and reference numerals 41 to 44 are optical fibers for optically connecting transmission / reception devices 31 to 34 and input / output ports of the AWG 40. The configurations of the transmission / reception device (2) 32 to the transmission / reception device (N) 34 are the same as those of the transmission / reception device (1) 31.

In this embodiment, a 1 × N AWG is used as the multiplexer 37 and the demultiplexer 38, and a 2 × 2 thermo-optical switch (TOS) is used as the two-input two-output optical path switch 39.
W) was used. When the 2 × 2 TOSW 39 is operated in the cross state, the optical signal from the transmitting device 35 is guided to the multiplexer 37, and the optical signal from the demultiplexer 38 is guided to the receiving device 36. Normally, the 2 × 2 TOSW is set to this state. On the other hand, 2 ×
When the 2TOSW 39 is set to the bar state, the signal from the demultiplexer 38 is guided to the multiplexer 37 and returned to the optical fiber 41 connected to the AWG 40. At that time, the transmitting device 3
The optical signal from 5 is looped back to its own receiving device 36. Since there are N 2 × 2 TOSWs 39 corresponding to each wavelength of the WDM signal, the above switch setting can be performed independently for each wavelength. The connection of 2 × 2 TOSW is different,
Even if the bar state is a normal setting state, there is no problem in the effect of the present invention. Also, the AWG 40 and the transmitting / receiving device 31
In the connections # 34, the i-th input port (i is an integer of 1 or more and N or less) and the (N-i + 1) -th output port of the AWG 40 are connected to the transmitting / receiving device i.

FIG. 2 shows the demultiplexing characteristics of the periodic input / output relationship of the AWG and the port connection relationship between each transmitting / receiving device and the AWG in the full mesh WDM transmission network device of the present embodiment, for the case of N = 8. FIG. AWG
Are the same as those in FIG. 6 shown in the conventional example. The connection relationship between each transmitting device and the input port of the AWG is the same as the conventional example, but the connection relationship between each receiving device and the output port of the AWG is the output port (N-i + 1) = (9-
i).

FIG. 3 is a diagram for explaining the operation of the present embodiment. Reference numerals 45 to 52 in the figure denote transmission / reception devices (1) to (8), 5
3 is 8 × 8 AWG. The numbers of the transmission / reception devices 45 to 52, the demultiplexing characteristics of the AWG 53, the connection relationship between the AWG port and the transmission / reception device, and the like are the same as those described with reference to FIG.
When it is desired to deliver a signal from the transmission / reception device (1) 45 to the transmission / reception device (3) 47, if the optical signal of the wavelength λ ₃ is transmitted from the transmission / reception device (1) 45 according to the demultiplexing characteristic of FIG. Is sent to the transmission / reception device (3) 47.

Here, it is assumed that a failure occurs in the transmission device of the transmission / reception device (1) 45 at the wavelength λ ₃ and the optical signal of the wavelength λ ₃ cannot be output. In this case, it is impossible to directly transmit a signal to the transmission / reception device (3) 47. Therefore, the 2 × 2 TOSW of the transmitting / receiving device (6) 50 corresponding to the wavelength λ ₈
× 2 TOSW is operated, and the transmitting and receiving device (6) 50 transmits the wavelength λ ₈
So that is folded back. Next, the transmitting / receiving device (1) 45
When an optical signal having a wavelength of λ ₈ is transmitted from, a signal is transmitted to the transmission / reception device (6) 50 through the AWG 53 according to the demultiplexing characteristic of FIG. Since the 2 × 2 TOSW is set in the transmitting / receiving device (6) 50 so that the wavelength λ ₈ is folded, the wavelength λ ₈ is transmitted again from the transmitting / receiving device (6) 50 to the AWG 53,
According to FIG. 2, the wavelength λ ₈ transmitted from the transmitting / receiving device (6) 50
Is sent to the transmission / reception device (3) 47. As explained above, the signal transmission from the transceiver (1) 45 to the transmitting and receiving device (3) 47 can be realized via the transceiver (6) 50 using the wavelength lambda ₈ in place of the wavelength lambda _3.

Here, since the optical signal is bypassed without converting the optical signal into electricity, there are no restrictions on the signal transmission speed, protocol, and the like. In addition, the transmitting / receiving device (6) 5
Even at 0, signal transmission using a wavelength other than the wavelength λ ₈ can be executed without any problem. further,
When the 2 × 2 TOSW corresponding to the wavelength λ ₇ of the transmission / reception device (5) 49 and the transmission / reception device (7) 51 is operated to be turned back, and the wavelength λ ₇ is transmitted from the transmission / reception device (1) 45, the transmission / reception device
(7) Transmission / reception device via 51 and transmission / reception device (5) 49
(3) A signal can be sent to 47.

Here, the wavelength λ ₃ at the transmitting / receiving device (1) 45
However, since the bypass of the wavelength λ ₈ can be set independently irrespective of the wavelength λ ₃ , the transmission / reception device (1)
A plurality of signals can be transmitted simultaneously between the transmission / reception device 45 and the transmission / reception device (3) 47, and the transmission capacity can be temporarily increased. Also, here, the transmitting / receiving device (1) 45 and the transmitting / receiving device (3)
Although only the transmission path between 47 has been described, it is obvious from FIG. 2 that a similar transmission path can be formed between other transmission / reception devices. Further, the connection relationship between the AWG port and the transmission / reception device is not limited to only the combination shown in FIG. 2, and other connection relationships that realize the same operation as the present embodiment are also included in the present invention. Is also self-evident.

[0017]

As described above, according to the present invention,
It is possible to realize a full mesh optical wavelength division multiplexing transmission network device that can cope with a failure of a transmission device or a reception device of an optical specific wavelength and can expand the transmission capacity between specific transmission and reception devices as needed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration example of an optical wavelength division multiplexing transmission network device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a demultiplexing characteristic of a periodic input / output relationship of the AWG according to the embodiment and an example of a port connection relationship between each transmitting / receiving device and the AWG in the embodiment.

FIG. 3 is an explanatory diagram showing an operation example of the optical wavelength division multiplexing transmission network device according to the embodiment.

FIG. 4 is an explanatory diagram showing an example of a conventional full mesh WDM transmission network device.

FIG. 5 is a block diagram illustrating a schematic configuration example of a conventional full mesh WDM transmission network device.

FIG. 6 is an explanatory diagram showing an example of a demultiplexing characteristic of a conventional AWG periodic input / output relationship and an example of a port connection relationship between each transmitting / receiving device and the AWG in the conventional device.

FIG. 7 is an explanatory diagram showing an operation example of a conventional optical wavelength division multiplexing transmission network device.

[Explanation of symbols]

 31-34, 45-52 Transmitter-receiver 35 Transmitter 36 Receiver 37 Coupler 38 Divider 39 2-input 2-output optical path switch 40, 53 Waveguide Diffraction grating multiplexing / demultiplexing circuit (AWG) 41-44 Optical fiber

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Akatsu 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Kazutoshi Kato 2-3-1 Otemachi, Chiyoda-ku, Tokyo 1 Nippon Telegraph and Telephone Corporation (72) Mitsuru Harada Inventor 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Junichi Akahan 2-3-Otemachi, Chiyoda-ku, Tokyo No. 1 Inside Nippon Telegraph and Telephone Corporation (72) Inventor Atsushi Takahara 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-8-242208 (JP, A) JP-A-8-307361 (JP, A) JP-A-4-192940 (JP, A) Hiroshi Takahashi, Kazuhiro Oda, Hiromu oba, Impact of Crosstalk in an A rrayed-Waveguide M ultiplexer on NxN Optical Interconne ction, Journal of L ightwave Technolog y, the United States, Vol. 14, No. 6,1097 -1105 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 10/00-10/28 H04J 14/00-14/08 H04Q 3/52 JICST file (JOIS)

Claims (3)

(57) [Claims] An array waveguide diffraction grating type multiplexing / demultiplexing circuit having N (N is a plurality) input ports and N output ports; An optical wavelength division multiplexing transmission network device having a star network configuration including N input / output ports and N number of transmission / reception devices optically connected, wherein the array waveguide diffraction grating type multiplexing / demultiplexing circuit has a periodicity. The transmission / reception device is configured to demultiplex an optical signal input from one predetermined output port of the arrayed waveguide grating type multiplexer / demultiplexer circuit into N wavelengths. A demultiplexing circuit that outputs the demultiplexed optical signal from the N output ports; a transmission circuit that transmits the N wavelength optical signal from the N output ports; and an N output port that transmits the N wavelength optical signal. Receiving circuit and N input ports The optical signal multiplexes La inputted N wavelengths, predetermined one of said arrayed waveguide grating type multiplexing and demultiplexing circuit
A multiplexing circuit that outputs to an input port of the book, a state in which an output port of the demultiplexing circuit is connected to an input port of the receiving circuit, and an output port of the transmitting circuit is connected to an input port of the multiplexing circuit. Connecting an output port of the transmission circuit to an input port of the reception circuit, and
N wavelength-division multiplexing switches for switching the output port of the demultiplexing circuit to the input port of the multiplexing circuit for each wavelength. Transmission network equipment. 2. In the connection between the array waveguide diffraction grating type multiplexing / demultiplexing circuit and the transmitting / receiving device, the number i (i is an integer of 1 or more and N or less) of the arrayed waveguide diffraction grating type multiplexing / demultiplexing circuit.
And the (N−i + 1) th output port is
2. The optical wavelength division multiplexing transmission network device according to claim 1, wherein the transmission device and the reception device forming a pair are connected using an optical fiber. 3. The thermo-optical switch according to claim 1, wherein the N 2-input 2-output optical path change-over switches are thermo-optical switches utilizing a thermo-optical effect of a quartz-based planar light wave circuit. 2. The optical wavelength division multiplexing transmission network device according to item 1.