JP2001268055A - Optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication system that a server can economically serve diversified services to each user and add/revise the served services for each user. SOLUTION: The optical communication system assigns wavelengths λ1, λ2, λ3 corresponding to provided services A, B, C to optical signals, optical transmitter-receiver sets 1-11-1-13 of the server transmit the optical signals, to which the different wavelengths are assigned, to optical transmitter-receiver sets 1-81-1-85 of a user side via an optical communication channel 1-7, the optical communication channel is provided with wavelength selection devices 1-91-1-93 by which the wavelength of a passing light can be selected by each user or each group and whose wavelength band can be variable, and applying variable control to the wavelength band of the wavelength selection devices to set the wavelength of the optical signal outputted to each optical transmitter-receiver can add and revise the service provided to each user.

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, and more particularly, to an optical communication system for communicating an optical signal via an optical communication network.

[0002]

2. Description of the Related Art There is a demand for the construction of a communication network that can economically use various communication services such as telephone, computer communication, and broadcasting. As one form of a network that economically provides such multimedia services, a system called an FTTH system that connects an optical fiber between a service provider and a user is well known. In a network using an optical fiber, higher-speed data communication of digital video transmission becomes possible. Further, in the FTTH system described above, a part of the optical communication equipment is shared by a plurality of users, so that a communication service can be provided more economically.

[0003] In such an FTTH system, a plurality of services are provided using a wavelength multiplexing (WDM) technique (for example, "Utilization experiment for CATV video transmission (Tachikawa /
Urayasu / Yokosuka) ", Terada Akira / Hirano Tsuyoshi / Soejima Shoji, NTT
Technical Journal (February 1997), Vol. 9, N
o. 2, pp 77-83, 1997). In this document,
F that shares an optical communication network with multiple users
Each type of type A and type B in which ISDN service and video service are service-multiplexed by the wavelength multiplexing technology on the TTH system is shown.

In such a configuration example, as shown in FIG. 7, a PD using an optical fiber is used between a service provider and a user.
They are connected in a form called S. Specifically, a passive optical branching device is inserted in the middle of the optical communication path extending from the service provider, and the optical fiber is connected by drawing the branched optical fiber to each user. Also, a wavelength of 1.5 μm is assigned to the video service, and a wavelength of 1.3 μm is assigned to the ISDN service and the video control to provide a plurality of services by wavelength multiplexing.

[0005] In the case of the type A (experiment at Tachikawa), a multi-channel video signal is analog frequency multiplexed (FD).
M) is transmitted. This method is a so-called broadcast network in which images of all channels are transmitted to a user. Each user can select a video signal of a desired channel from video signals of other channels provided by the service provider using a channel selection device provided in his / her own terminal.

On the other hand, type B (experiment in Urayasu and Yokosuka)
In the case of the system, multi-channel digital video signals are time-multiplexed and transmitted by the ATM communication system. This is a so-called communication type network in which only the channel selected by the service provider is transmitted to the user according to the request.
In this method, a service provider can make settings such as addition and change of services for each user by using an ATM technology.

[0007]

FIG. 8 shows the type A described above.
And the characteristics and problems of each type B are shown. According to FIG. 8, in the case of the type A system, multiple channels (about 250
Channel). Also,
As described above, each user can freely select and receive a desired video signal from all the video signals provided by the service provider. However, in the type A system, it is difficult to set a provided service for each user, and it is difficult to restrict the provided service for each user. In addition, since frequency multiplexing is used as a multiplexing method, an additional electric system is required for performing services other than video broadcasting (for example, computer communication), which has a disadvantage that the device configuration is complicated. .

On the other hand, in the case of the type B system, service setting for each user is easy as described above. The ATM communication system used for type B has better compatibility with multimedia services such as computer communication than type A. However, since the network bandwidth is shared by the entire users, when high-speed communication such as video transmission is performed, the number of channels that can be selected by the user is limited to several channels (about two channels). . In addition, for example, in order to add a higher-speed service, even a user who does not use such a new high-speed service needs to renew the communication device (eg, increase the bit rate), which is economical and quick. There is also a problem that the equipment cannot be renewed.

[0009] The present invention has been made in view of the above-described problems, and has as its object to provide a service provider with various services using an optical communication network shared by a plurality of users. Is to be provided economically to each user, and the service provided to the user can be easily and quickly added and changed for each user.

[0010]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a plurality of optical transceivers for transmitting each optical signal to which a different wavelength is assigned,
And a second input / output port, multiplexes the wavelengths of the optical signals from the optical transceivers respectively connected to the plurality of first input / output ports, and outputs the multiplexed signals to the second input / output port.
A wavelength combining / branching device for branching the wavelength of the optical signal from the second input / output port and outputting the branched signal to a plurality of first input / output ports; and a third input / output port, The optical signal output from the output port and passed through the third input / output port is branched and output to a plurality of fourth input / output ports. And an optical communication path for outputting to the third input / output port, and a plurality of optical transmission / reception devices respectively connected to the plurality of fourth input / output ports. A wavelength selecting device capable of selecting a wavelength of an optical signal output to a plurality of optical transmitting / receiving devices for each optical transmitting / receiving device, and a variable wavelength band to be selected; and the wavelength band selected by the wavelength selecting device. And a management control unit that performs management and control of It is obtained by the wavelength band to be selected by the length selector to set the wavelength of the optical signal provided by variably controlling the respective optical transceiver. Further, the wavelength selection device is configured to select the wavelength of the optical signal from the optical transceiver to the optical transceiver for each of the plurality of optical transceivers.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a network to which the present invention is applied. In FIG. 1, reference numeral 1-1 denotes each optical transmitting / receiving apparatus 1 to be disposed in a building of a service provider.
An optical transmission / reception unit composed of 11, 11-12, and 1-13. A service provider that provides a video service or the like to a user assigns a different wavelength for each of the services A, B, and C to each of the optical transmission / reception devices 1 to 11. 11, 11-12, and 1-13 to provide a plurality of services. That is, each service A, B,
Different wavelengths λ1, λ2, λ3 are assigned to the optical transmitting / receiving unit 1-1 that provides C, respectively. Between the optical transmitting / receiving section 1-1 of the service provider and the optical transmitting / receiving section 1-8 of the service user, the wavelength multiplexing / demultiplexing device 1-4 and the optical communication path 1-
7 are connected.

The wavelength multiplexing / demultiplexing apparatus 1-4 includes a plurality of input / output ports 1-21, 1-22, 1-23 to which a plurality of optical transmitting / receiving apparatuses 1-11, 11-12, and 1-13 are connected. And input / output ports 1-3, and input / output ports 1-21, 1
-22, 1-23, and wavelength division multiplexing of the optical signal from the input / output port 1-3 to the input / output port 1-3 side. 2
2, 1-23.

The optical communication path 1-7 includes a wavelength multiplexing / demultiplexing device 1-4.
I / O port 1-5 connected to I / O port 1-3
And a plurality of input / output ports 1-61 to 1-65 connected to the optical transmission / reception unit 1-8. −65 side and input / output ports 1-61 to 1-6
5 are focused and output to the input / output ports 1-3. Optical transmission / reception unit 1-8 as user equipment
Is an optical transceiver 1-8 used by each of a plurality of users.
1 to 1-85, each of the optical transceivers 1-81 to 1-85.
85 is a plurality of input / output ports 1-61 to 61 of the optical communication path 1-7.
Each is connected to 1-65.

Here, in the optical communication path 1-7, a plurality of optical transmitting / receiving apparatuses 1-81 to 1-8 are transmitted from the wavelength multiplexing / demultiplexing apparatus 1-4.
It is possible to limit the wavelength of the passing optical signal on the route to 5 in each of the optical transceivers 1-81 to 1-85 or in units of a plurality of optical transceivers (that is, in units of groups),
Plurality of wavelength selectors 1-91 with variable passing wavelength band
To 1-93 are provided. The management and control of the passing wavelength bands of the wavelength selection devices 1-91 to 1-93 are performed by the management control system 1-10.

In the example of FIG. 1, the management control system 1-10
As a result, the pass wavelength bands λ1 and λ2 are individually set for the wavelength selecting devices 1-91 and 1-92. This allows
Optical transmission / reception devices 1-11, 1-1 on the service provider side
2, the services A and B corresponding to the wavelengths λ1 and λ2 provided by the respective wavelength selecting devices 1-91 and 1-92 are selected by the wavelength selecting devices 1-91 and 1-92, and the optical transmitting and receiving devices 1-81 and 1-82 on the user side.
Sent to That is, the service provided from the service provider to the user can be set for each user. In FIG. 1, the management control system 1-10 sets a pass wavelength band λ3 for the wavelength selection device 1-93. Thereby, the optical transmitting and receiving device 1-1 on the service provider side
The service C according to the wavelength λ3 provided from the third unit 3 is selected by the wavelength selection device 1-93 and sent to each of the optical transmission / reception devices 1-83 to 1-85 on the user side. That is, the service provided from the service provider to the user can be set for each group.

The optical communication path 1-7 can take various forms such as a star type, a ring type, a bus type, or a combination thereof as shown in FIG. The services available to each user include a wavelength selector 1-9 in the optical communication path 1-7.
As described above, control is performed for each user or for each group. As shown in FIG. 1, the passband of the wavelength selector 1-9 can be changed in bandwidth or center frequency by using a technique such as a wavelength tunable filter. The services available to the user are controlled by the passband,
Depending on the passing wavelength band, it is possible to provide a single user with a plurality of services corresponding to, for example, the wavelengths λ1 and λ2.

In the present embodiment, the service provider controls the wavelength selector 1-9 using the management control system 1-10. As a result, it is possible to provide various services according to individual requests of users. Here, the service provider changes the pass wavelength band only for the wavelength selection device corresponding to the change requester for the change request of the used service. In addition, each optical transmitting / receiving device 1- on the user side.
As for 81 to 1-85, only the person who wants to change the device, etc., if necessary, and the other users do not change the device. Therefore, it is possible to respond more economically and promptly to a change request of a certain user than to change the device of another user.

As described above, in the present embodiment, services are assigned to wavelengths, and the wavelengths corresponding to the services available using the wavelength selection device are set by the service provider for each user. Services can be provided economically to users (users), services can be easily set in response to various user requests, and future services can be added and changed. Can also respond quickly and economically.

FIG. 3 is a block diagram showing the first embodiment. In the first embodiment shown in FIG. 1, for example, the wavelength λ1 of the optical signal is assigned to the telephone service, and the wavelength λ2
Is assigned to the IP communication service, and the wavelength λ3 is assigned to the broadcast-type video service. Transmission signals (downlink signals) from the optical transceivers 2-11 to 2-13 that provide each service are multiplexed once by the WDM coupler 2-2 and branched by the optical coupler 2-3. The transmission wavelength λ1
The tunable filter 2-4 capable of controlling λ3 controls a service provided to the user side, and is managed and controlled by the control terminal 2-5.

The optical coupler 2-6 is used for further splitting the optical signal having the wavelength λ3. A predetermined optical signal is transmitted to the user via the optical fiber network 2-7.
Each user transmits an optical signal to its own optical transceiver 2-81.
~ 2-85. On the other hand, the transmission signal (uplink signal) from each user follows the reverse path of the downlink signal.

According to the first embodiment, a plurality of services having different characteristics such as telephone, IP communication, and broadcast video can be provided while sharing a part of the optical equipment.
The wavelength of the signal light corresponding to the service provided to each user can be managed by the service provider on a user basis. Therefore, by providing only necessary signals to each user according to the user's request, the service provider can manage and control the services used by each user. The service change is performed on a user basis, and other users who do not change the service can use the conventional service as it is. As described above, in the first embodiment, various services can be economically provided to the user, the service can be easily set in response to the request of the various users, and further services can be added and used. Changes can be made economically and promptly.

FIG. 4 is a block diagram showing a second embodiment. In the second embodiment shown in FIG. 4, wavelengths λ1 and λ2 of an optical signal are allocated to IP connection services of different service providers, and a wavelength λ3 is allocated for network control. Optical transceivers 3-11 to provide each service
The transmission signal (downlink signal) from 3-13 is once multiplexed by the WDM coupler 3-2 and branched by the optical coupler 3-3.
An optical signal is transmitted to the user via the optical fiber network 3-4. Wavelength tunable filter 3 provided for each user
Reference numeral 5 is inserted to individually control the passing wavelength for each user from outside according to a control signal transmitted using the wavelength λ3. Each user receives an optical signal with its own optical transceiver 3-61 to 3-63.

According to the second embodiment, each user can use a plurality of service providers that provide the IP connection service while sharing a part of the optical equipment. The service provider that can be used by each user can be managed and controlled by the user on a user-by-user basis, thereby preventing unauthorized access by the user. Therefore, in the second embodiment, various services can be economically provided to the user even when the user has a variable wavelength selection device for restricting the service, and the user can easily meet various user requests. Service can be set, and it is possible to respond economically and promptly to future additions and changes of services.

FIG. 5 is a block diagram showing a third embodiment. In the third embodiment shown in FIG. 5, a plurality of services are assigned to each of the wavelengths λ1 to λ3 of the optical signal. Transmission signals (downlink signals) from the optical transceivers 4-11 to 4-13 that provide each service are multiplexed once by the WDM coupler 4-2, and are multiplexed to the optical ring 4-4 via the optical coupler 4-3. Is entered. Optical signals are transmitted to the user via the optical rings 4-4 and the respective optical couplers 4-3. Each user receives an optical signal with each of the optical transceivers 4-51 to 4-53.

Further, the sub-ring 4
The optical signal is also delivered to -6. The optical ring 4-4 and the sub ring 4-6 are connected in a chain. A tunable filter 4-7 is inserted in the optical fiber line connecting the optical ring 4-4 and the sub ring 4-6. The passing wavelength of the wavelength tunable filter 4-7 is controlled using, for example, a part of the signal frame of the wavelength λ1 as a control signal. As a result, the service provider can set the sub-ring 4
The service provided to each user via each of the optical transceivers 4-54 and 4-55 connected to -6 can be managed and restricted.

According to the third embodiment, each user can use a plurality of services while sharing a part of the optical equipment. The service provider can manage and control services available to the users belonging to the sub-rings 4-6 on a group basis. Therefore, in the third embodiment, various services can be economically provided to users even in various network forms such as rings, and service settings can be easily performed in response to various user requests. It is possible to respond economically and promptly to future additions and changes of services.

FIG. 6 is a block diagram showing a fourth embodiment. In the fourth embodiment shown in FIG. 6, for example, an ISDN service is assigned to a wavelength λ0 (1.3 μm band) of an optical signal, and an IP communication service is assigned to each of the wavelengths λ1 to λ3 (all 1.5 μm band). Allocate broadcast video service and communication video service. Transmission signal (downlink signal) from optical transceiver x-11 providing ISDN service
Is branched by an optical coupler x-3 and transmitted to a user via an optical fiber network x-4. Each user receives an optical signal through its own optical transceiver x-51 to x-53. The transmission signal (uplink signal) from each user has the same wavelength λ
0 is used to follow a path opposite to the downlink signal. They are,
It is known as a basic configuration of a conventional FTTH system.

On the other hand, the transmission signals (downlink signals) from the optical transmission / reception devices x-12 to x-14 which provide each service using the wavelengths λ1 to λ3 of the optical signals are once transmitted to the WDM coupler x-2.
Wavelength λ that is further combined with
The optical signal of 0 is multiplexed with the WDM coupler x-6. The multiplexed optical signal is transmitted to the user along the same route as the optical signal providing the ISDN service. The optical signals of the wavelengths λ1 to λ3 that provide the respective services are converted into the optical signals of the wavelength λ0 and the wavelengths λ1 to λ by using the WDM coupler x-56 inside the optical transceivers x-51 to x-53 of each user.
The optical signal is split into three optical signals. The wavelength tunable filter x-57 that can individually control the passing wavelengths λ1 to λ3 from the outside,
It controls services provided to users. The control of the wavelength tunable filter x-57 includes the above-described conventional F
As in the TTH scheme, an optical signal of wavelength λ0 that provides an ISDN service is used. According to the fourth embodiment, the service provider can use the configuration of the conventional FTTH system and add some optical equipment and the like,
It is possible to provide services having different characteristics such as an IP communication service and a video service.

As described above, in the optical communication network, the service provider can provide various services economically to the user by using the optical communication network shared by a plurality of users, and provide the user with the service. Services to be provided can be easily added or changed.

[0030]

As described above, according to the present invention, each optical signal to which a different wavelength is assigned can be transmitted from an optical transceiver to a plurality of optical transceivers via an optical communication path. A wavelength selector is provided in the optical communication path, wherein the wavelength of the optical signal is selectable for each optical transmitter / receiver and the wavelength band is variable, and each optical transceiver is variably controlled by controlling the wavelength band of the wavelength selector. When providing a service to each user, the service provider assigns each service to each wavelength of the optical signal and sets each wavelength from its own optical transceiver. The service provider can set the service to be provided to each user on a user-by-user basis while transmitting to the user's optical transmission / reception device side. It is possible to provide, can make service settings easily to demands of various users of the service, it can be economically and quickly respond even to additional and modification of future service. Also,
Since the wavelength of the optical signal from the optical transceiver to the optical transceiver is selected for each of the plurality of optical transceivers, one service can be provided to a plurality of users.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a network to which the present invention is applied.

FIG. 2 is a diagram showing a form of a network to which the present invention is applied.

FIG. 3 is a block diagram showing a first embodiment of the network.

FIG. 4 is a block diagram showing a second embodiment of the network.

FIG. 5 is a block diagram showing a third embodiment of the network.

FIG. 6 is a block diagram showing a fourth embodiment of the network.

FIG. 7 is a diagram showing a configuration of a conventional network.

FIG. 8 is a diagram showing features and problems of a conventional network.

[Explanation of symbols]

1-1, 1-8, 2-1, 2-8, 3-1, 3-6, 4
-1, x-1, x-5... Optical transmission / reception unit, 1-11 to 1-1
3, 1-81 to 1-85, x-11 to x-14, x-5
1 to x-55: optical transmission / reception device, 2-11 to 2-13, 2
-81 to 2-85, 3-11 to 13-13, 3-61 to 3
-63, 4-11 to 4-13, 4-51 to 4-55 ... optical transceiver, 1-21 to 1-23, 1-3, 1-5, 1-
61 to 1-65 input / output ports, 1-4 wavelength combining / branching apparatus, 1-7 optical communication path, 1-9 wavelength selecting section, 1-91
1093: wavelength selection device, 1-10: management control device,
2-2, 3-2, 4-2, x-2, x-6, x-56 ...
WDM coupler, 2-3, 2-6, 3-3, 4-3, x-
3: optical coupler, 2-4, 3-5, 4-7, x-57: wavelength tunable filter, 2-5: control terminal, 2-7, 3-4
x-4: optical fiber network, 4-4: optical ring, 4-6: sub-ring.

Claims (2)

[Claims] 1. An optical communication network for communicating optical signals, comprising: a plurality of optical transceivers for transmitting optical signals assigned to different wavelengths to respective ones; and first and second input / output ports. Multiplexing the wavelength of the optical signal from the optical transceiver connected to each of the plurality of first input / output ports, outputting the multiplexed wavelength to the second input / output port, and multiplexing the optical signal from the second input / output port. A wavelength multiplexing / branching device for branching a wavelength and outputting the wavelength to a plurality of first input / output ports; and a third and fourth input / output port, wherein the third input / output is output from the second input / output port. Optical communication for branching an optical signal via an output port and outputting the branched signal to a plurality of fourth input / output ports, and converging optical signals from the plurality of fourth input / output ports and outputting the collected optical signal to a third input / output port Path and multiple fourth input / output ports And a plurality of optical transmitting and receiving devices connected to the optical transmitting and receiving device, the wavelength of the optical signal output from the wavelength multiplexing / branching device to the plurality of optical transmitting and receiving devices provided in the optical communication path is provided for each optical transmitting and receiving device. A wavelength selection device that is selectable and has a variable wavelength band to be selected, and a management control unit that manages and controls the wavelength band selected by the wavelength selection device, and is selected by the wavelength selection device. A wavelength of an optical signal to be provided to each optical transceiver by variably controlling the wavelength band. 2. The optical communication system according to claim 1, wherein the wavelength selection device selects a wavelength of an optical signal from the optical transceiver to the optical transceiver for each of a plurality of optical transceivers.