JP3334966B2 - Concentrator and optical communication network using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentrator for constructing an optical communication network in which a loop-type optical communication system and a circuit-switching or star-type optical communication system are combined. It relates to an optical communication network.

[0002]

2. Description of the Related Art An optical LAN using an optical fiber as a transmission line has been developed in order to cope with an increase in the capacity of an information signal and an expansion of a network, and connects between a LAN backbone and a workstation (WS) by an electric signal. It has been used as a LAN. Data system L for optical LAN
There are AN and video LAN, but typical LA of data
N, FDDI (Fiber Distribut)
ed Data Interface). FDD
The network configuration of I is shown in FIG. In this configuration, stations (nodes) are connected by a link using an optical fiber transmission line. The stations are divided into a duplex station 911 and simplex stations 901, 902,...
One link forms a double ring. One of the double rings 941 is used for actual data transmission, and the other 942 is used in the event of a failure. The single station has only one link, and is connected to concentrators 921, 922, and 923 that can connect a plurality of single stations by an upstream optical fiber 951 and a downstream optical fiber 961, thereby forming a single ring. The concentrator is a station dedicated to wiring, and a single station is arranged in a star configuration. On the other hand, a video LAN handles large-capacity information, so an ultra-large-capacity communication path is required, and it is low-priced for use in general offices. Equipment has not yet been developed. However,
In wide area networks, optical CATV and broadband ISDN (B-I
SDN) is being considered, in which subscribers are connected in a star configuration centering on the center station, and the center station and each subscriber, or each subscriber, can communicate large-capacity information such as video with each other. It was made. The above FDD
In a loop-type optical LAN such as I, a signal handled by a station (node) is converted into the speed of a transmission line and added and dropped. There is a problem that causes a circuit load. Also, in the case of a star-type optical network such as a CATV, when time-division multiplex communication is performed, signal collision avoidance control is performed. In order to solve these problems, the two are integrated, and the line is separated according to the type of signal, such as transmitting a time-division signal to a loop-type LAN and transmitting a large-capacity signal to a star-type LAN. A loop-type and star-type mixed network has been studied. FIG. 10 shows a configuration example of the above network.
.., 1015 are nodes, 1021 is a loop line transmission line, 1022 is a loop line backup transmission line, and 1023 is a star line transmission line.
A time-division signal such as FDDI is transmitted on the loop line, and a large-capacity signal such as a video signal is transmitted on the star line, thereby compensating for the disadvantages of both.

[0003]

However, in the above-mentioned network, the transmission paths are arranged separately from each other.
The total transmission path length is long, and expansion is difficult.

Accordingly, the applicant of the present invention has filed an application (Japanese Patent Application No. 4-292963) to solve these problems. In this application, a concentrator capable of integrally handling a loop line and a star line and an optical communication network using the same have been proposed. FIG. 11 shows a configuration example of the concentrator. The present invention is a further improvement of the present invention. Specifically, in a concentrator for integrally handling a loop line and a star line, the present invention proposes a communication technology that arbitrarily uses the two types of transmission paths according to the situation. Things.

[0005]

According to the present invention, there are provided a plurality of ports arranged in a predetermined order, means for separating a wavelength division multiplexed optical signal input from the port by wavelength, and A concentrator comprising: means for sequentially delivering a part to a plurality of ports in the predetermined order; and means for delivering another part of the separated optical signal to at least one arbitrary port. A means for sequentially delivering the separated optical signal to a plurality of ports in the predetermined order, or a means for arbitrarily selecting and connecting to the means for delivering to the arbitrary port. To solve the above problem.

In the present application, one port is composed of an input port for inputting an optical signal and an output port for output of an optical signal, or one input / output having both functions. Ports or portions thereof are constituted by ports, and in the following description, portions within a port are specified by using the terms input port and output port only when particularly necessary for explanation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0008]

(Embodiment 1) FIGS. 1, 2 and 8 show a first embodiment of the present invention. FIG. 1 shows an embodiment of a concentrator according to the present invention, and FIGS. 2 and 8 show examples of the configuration of an optical communication network using the same. FIG. 3 shows a configuration example of a node suitably used in the optical communication network. First, each configuration will be described with reference to the drawings.

In FIG. 1, reference numeral 11 denotes N input terminals 12.
, 12N and N output terminals 131, 1
, 13N, 121 × 131, 122 and 132,..., 12N
And 13N correspond to one set (a pair) of input / output terminals. The optical switching unit 11 controls one or more arbitrary output terminals (for example, arbitrarily selected 131, 13) by controlling with an external control signal.
2 and 134). Also, 141, 142,..., 14N
Are optical demultiplexers for demultiplexing the wavelength-division multiplexed light input from the input ports 161, 162,..., 16N of the concentrator according to the present embodiment for each wavelength, and the output terminal of each demultiplexed optical signal is Optical switches 1111 to 1113, 112
.., 11N1 to 11N3. Reference numeral 1111 denotes an optical switch for switching an optical signal of a certain wavelength (here, temporarily set to be λ1) transmitted from the optical demultiplexer 141 to the optical multiplexer 91 or the optical switch 1221. Thus, switching control of the optical signal is performed. Line management control unit 11
The control signal from 0 is transmitted through the transmission line shown by the dotted line in FIG. Also, each optical switch 1112, 1113, 11
21, 1122, 1123,..., 11N1, 11N
2, 11N3 is used in the same manner as the optical switch 1111 and is an optical multiplexer connected to each optical switch or an optical switch 1222, 1223, 1231, 1232, 123.
The optical signal is switched to 3,..., 12N1, 12N2, 12N3. An optical switch 1221 selects an optical signal of λ1 wavelength of either the optical switch 1111 or the optical wavelength demultiplexer 102 and sends out the optical signal to the optical multiplexer 152. The optical switch is controlled. Also, each optical switch 1211, 121
Are used in the same manner as the optical switch 1221, and the optical demultiplexer connected to each optical switch or the optical switches 11N1, 11N2,
One of the optical signals 11N3, 1112, 1113,... Is selected. 151, 152, ..., 15N
Are optical multiplexers for multiplexing optical signals from a plurality of optical switches, respectively, and the output terminals of the optical multiplexers are output ports 171, 172,... Of the concentrator 10 of the present embodiment.
, Used as 17N. Also, 91, 92, ...
., 9N are optical multiplexers for multiplexing optical signals transmitted from the respective optical switches, and are respectively connected to a plurality of optical switches. , 9N are connected to input ports 121, 122,..., 12N of the optical switching unit 11 of the concentrator 10 of the present embodiment. , 10N are output ports 131, 132,... Of the optical switching unit 11, respectively.
.. an optical demultiplexer for demultiplexing the wavelength multiplexed light output from the 13N into each wavelength, and each output terminal is an optical switch 1211,
1212, 1213, 1221, 1222, 1223
.., 12N1, 12N2, and 12N3.

Next, in FIG. 2, reference numeral 10 denotes a concentrator according to the present embodiment whose configuration example has been described with reference to FIG. 1. Here, a case where the number of ports is eight is shown. 21
, 217, 218 are nodes 23
1, 232,... 237, 238 are optical fibers (uplink optical fibers) for transmitting the optical signals to the concentrator 10;
, 162, ..., 167, 168. , 227, 228 are optical fibers (downstream optical fibers) for transmitting the output optical signal from the concentrator 10 to each node, and have output ports 171, 172,. 177, 178. Also,

FIG. 8 shows an optical communication network using the concentrator according to the present embodiment, and reference numerals 801 to 807 denote nodes.

In FIG. 3, reference numerals 31 and 32 denote output terminals and input terminals of the nodes, which are connected to the ports of the concentrator 10 via optical fiber transmission lines. 33 is an optical multiplexer for multiplexing the optical signals of each wavelength transmitted from each optical transmitter, the output terminal of which is connected to the output terminal 31 of the node, for transmitting the wavelength multiplexed light of the loop line and the switched line. I do. 3
4 is an optical demultiplexer for demultiplexing the wavelength-division multiplexed light by wavelength,
Its input is connected to the input 32 of the node. 36,
Reference numerals 37 and 38 denote optical transmitters having oscillation wavelengths λ1, λ2 and λ3, respectively, which convert video data or computer data into optical signals. 40, 41, 42 are optical receivers 40,
41 and 42 convert optical signals of wavelengths λ1, λ2 and λ3 into electric signals, respectively. Reference numeral 45 denotes a 3 × 3 switch, which converts computer information or video information input from a computer or an external input device into a line management control unit 110.
Switch to an optical transmitter having a wavelength determined by. Reference numeral 46 denotes a 3 × 3 switch for switching data received by each optical receiver to a computer or an external output device.

Next, the operation of the concentrator of the present embodiment and an optical communication network using the same will be described with reference to FIGS. This network is a communication system that connects a concentrator and each node on a star and handles multimedia information such as computer information and video information, and has a loop line and a switched line. The switching line is a line for delivering an optical signal transmitted from each terminal to an arbitrary terminal by the optical switching unit 11 in the concentrator 10, and transmits video information and the like. Loop lines allow computer information to be transmitted. The optical signals of the loop line and the switched line are wavelength-multiplexed in one optical fiber. For the optical path of the loop line and the switched line, for example, an optical signal of the switched line (here, it is assumed that an optical signal is transmitted from the node 231 at the wavelength λ1) is sent to the rising optical fiber 2.
11 → optical demultiplexer 141 in concentrator 10 → optical switch 1111 → optical multiplexer 91 → optical switching unit 11
It is assumed that an optical signal of λ1 wavelength has been delivered to the output port 132 of the concentrator 11. ) → optical demultiplexer 102 → optical switch 1221 → optical multiplexer 152 → downward optical fiber 2
22 and is input to the node 232 to form a switched line. The optical signal of the loop line (here, temporarily, the node 23
From 1 an optical signal is transmitted at wavelength λ3. It is described as. ) Indicates the rising optical fiber 211 → the optical demultiplexer 141 in the concentrator 10 → the optical switch 1113 → the optical switch 1223 → the optical multiplexer 152 → the downstream optical fiber 2
22 → passes through the path of the node 232, is electrically relayed by the node 232, and is output to the upstream optical fiber 212. Similarly, the nodes 232, 234,..., And 238 are transferred to form a loop line.

In this embodiment, λ1, λ
It is assumed that three wavelengths of 2, λ3 are used, and each wavelength is used for both a loop line and a switched line. In this network, λ1 and λ2 wavelengths are normally assigned to loop lines, and λ3 is assigned to switched lines. Now, temporarily,
The λ1 wavelength is used for communication conforming to the FDDI protocol, the λ2 wavelength is used for time division multiplex communication,
Assume that three wavelengths are used for a switched line that carries video information from node 235 to node 232. In this communication state, it is assumed that the time division multiplex communication of the wavelength λ2 has been completed, and the node 231 needs to transmit video information to the nodes 232 and 234 by using a switched line. The node 231 converts the optical signal of wavelength λ1 (FDDI line)
The request for use of the switched line for transmitting the video information is carried, and the line use request information is transmitted to the line management control unit 110 in the concentrator. The optical signal of the wavelength λ1 is
From 31, the light is sent to the upstream optical fiber 211 and input to the input port 161 of the concentrator 10. The optical signal of the wavelength λ1 is demultiplexed by the optical multiplexer 141, passes through the optical switch 1111 and the optical switch 1221, and
The signals are multiplexed at 52 and transmitted to the node 232 from the output port 172 of the concentrator 10. The optical signal of the wavelength λ1 input to the node 232 is electrically relayed and transmitted to the upstream optical fiber. Similarly, the optical signal of the wavelength λ1 passes through the concentrator 10 → the optical node 233 → the concentrator 10 → the optical node 234 →... → the optical node 238 and is input to the line management control unit 110 of the concentrator 10. The line management control unit 110 selects the wavelength λ2 as the switching line use permitted wavelength of the node 231 in response to the switched line use request. This means that wavelength λ2 was selected under the condition that wavelength λ3 assigned to the switched line is still used and wavelength λ2 of the loop line is unused. As a result, the available wavelengths on the network (the number of available lines) can be effectively used by utilizing the idle wavelengths of the loop lines. next,
The line management control unit 110 transmits the information of the selected wavelength to the wavelength λ1
To the node 231. Further, the line management control unit 110 switches the optical switch corresponding to the λ2 wavelength so that the optical signal path of the λ2 wavelength becomes the circuit switching type. That is, the optical switch 11 for the λ2 wavelength
12 to the optical multiplexer 91 and the optical switches 1222, 12
42 is switched to the optical multiplexers 102 and 104, respectively. The node 231 having received the information on the wavelength λ2 of the switching line from the line management control unit 110 controls the 3 × 3 switch 45, and controls the optical transmitter 3 having the oscillation wavelength λ2.
7 is input with video information. The video information is converted by the optical transmitter 37 into an optical signal having a wavelength λ2. The optical signal of wavelength λ2 is
After passing through the optical multiplexer 33, the optical fiber 2
11 is sent. The optical signal of the wavelength λ2 input to the input port 161 of the first port of the concentrator 10 is demultiplexed by the optical demultiplexer 141 and transmitted from the output terminal of the wavelength λ2. The transmitted optical signal of the wavelength λ2 passes through the optical switch 1112 switched to the switching line and is input to the optical multiplexer 91. The optical signal of the wavelength λ2 multiplexed by the optical multiplexer 91 is sent to the optical switching unit 11. The transmitted optical signal is output from the optical switching unit 11 to the output terminals 132 and 13.
4 distributed. The light output from the output terminal 132 is the wavelength multiplexed light transmitted from the nodes 231 and 235. The wavelength division multiplexed light is split by the optical splitter 102 into optical signals having the wavelengths λ2 and λ3. The optical signal of the wavelength λ2 is
The light is transmitted to the optical multiplexer 152 by the optical switch 1222 having the wavelength λ2, and is multiplexed again with the optical signal having the wavelength λ3 by the optical multiplexer 152. The wavelength multiplexed light of λ2 and λ3 is
From 72, it is sent to the down optical fiber 222. The wavelength-division multiplexed light input to the node 232 is converted by the optical demultiplexer 34 into λ
The optical signal having the wavelength of λ2 is demultiplexed into light having the wavelength of λ2, and the optical signal having the wavelength of λ2 is received by the optical receiver 41. Also, the optical signal of wavelength λ2 distributed to the output end 134 of the optical switching unit 11
Similarly, it can be received at node 234.

Next, it is assumed that the transmission of the video information of the node 231 has been completed and the node 232 needs to transmit the computer information to the node 231. The node 232 transmits the computer information by a time division multiplex communication method using a loop line. The node 232 puts the use request information of the loop line on the optical signal of the wavelength λ1, and transmits the line use request information to the line management control unit 110 in the concentrator. The optical signal path of the wavelength λ1 is the same as the path described for the switching line, and is omitted here. The line management control unit 110 selects the wavelength λ2 as the used wavelength of the loop line of the node 232 in response to the loop line use request. This selects λ2 because λ1 assigned to the loop line is currently used and wavelength λ2 of the switched line is unused. As a result, the unused wavelength allocated to the switched line can be effectively used. The line management controller 110 adds the information of the selected wavelength to the optical signal of the wavelength λ1 and notifies the node 232 of the information. Further, the line management control unit 110 switches the optical switch corresponding to the wavelength λ2 so that the optical signal path of the wavelength λ2 becomes a loop line. That is, the optical switches 1112 and 12 for the wavelength λ2
22, 1122 and 1232,..., 11N2 and 121
2 are directly connected. Node 2 that has received the information on the permitted wavelength λ2 of the loop line from the line management control unit 110
32 controls a 3 × 3 switch 45 to generate an oscillation wavelength λ.
The computer information is input to an optical transmitter 37 having a 2. The computer information is converted by the optical transmitter 37 into an optical signal having a wavelength λ2. The optical signal of the wavelength λ2 is supplied to the optical multiplexer 3
3 and is sent from the output end 31 to the optical fiber 212. The optical signal input to the input port 162 of the second port of the concentrator 10 is demultiplexed by the optical demultiplexer 142 and transmitted from the output terminal of the demultiplexer having a wavelength of λ2. The transmitted optical signal of the wavelength λ2 is transmitted to the adjacent optical switch 1232 by the optical switch 1122, and is transmitted to the optical multiplexer 153 in the optical switch 1232. The transmitted optical signal of the wavelength λ2 passes through the optical multiplexer 153 and is transmitted to the output port 173. The optical signal of the wavelength λ2 transmitted through the downstream optical fiber 223 and input to the node 233 is split by the optical splitter. The demultiplexed optical signal of the wavelength λ2 is converted into an electric signal by the optical receiver 41. The node 233 that has received the computer information analyzes whether the data is addressed to itself, and if necessary, electrically relays the data, converts the data to an optical signal of wavelength λ2 again by the optical transmitter 37, and outputs it. Dispatch from end 31. Similarly, the optical signal is
Concentrator 10 → Node 234 → Concentrator 10 → Node 235,.
Is transmitted to the node 231. The optical signal of the wavelength λ2 input to the node 231 is split by the splitter 34,
The light is received by the optical receiver 41. In this manner, a set of optical switches for the wavelength λ2 installed in each adjacent port is directly connected by the line management control circuit 110 to form a loop line.

Next, communication of an optical network formed by connecting a plurality of concentrators according to the present embodiment in a radial manner will be described with reference to FIG. However, the same operation as the operation of the network using one concentrator is omitted here.

Now, suppose that a communication request for a loop line is generated from the nodes 806 to 803, and the line management control unit 110 (this line management control unit is in the concentrator 813 connected to the node 806) is used for the switching line. The operation of allocating the unused wavelength of λ2 allocated to the loop line to the loop line will be described. The line management control unit 110 determines that λ2
The line management control unit 1 in each concentrator on the network notifies that the wavelength of the wavelength is newly allocated for the loop line.
10 and each node. Each concentrator 10
The line management control unit 110 of each of the optical switches 1112 and 122 corresponding to the wavelength λ2 in the concentrator respectively.
2, 1122 and 1232,..., 11N2 and 1212
Is connected directly. As a result, the optical signal path of the λ2 wavelength forms a loop line on this network.
After that, the node 806 sends an optical signal of λ2 wavelength,
6 → 813 → 811 → 812 → 801 → 812 → 802
An optical signal is transmitted through a loop line path of → 812 → 803.

Next, a switching line communication request is generated from the nodes 806 to 803, and the line management control unit 110 (this line management control unit is in the concentrator 813 connected to the node 806) is connected to the loop line. The operation of allocating the vacant wavelength of λ2 allocated for the switching line will be described. The line management control unit 110 notifies the line management control unit 110 in the concentrators 813, 811 and 812 on the network that the wavelength of λ2 is newly allocated for the switched line, and
The line management control unit 110 in 3,811,812 switches the optical switch corresponding to the wavelength λ2 so that the optical signal of the wavelength λ2 becomes the line switching type. After the switching-path optical path is established, the node 806 transmits an optical signal of the wavelength λ2, and the optical signal of the wavelength λ2 transmits the path of 806 → 813 → 811 → 812 → 803.

As described above, the loop type optical communication system and the circuit switching type optical communication system are simply connected to the concentrator of the present embodiment using the common optical fiber for the upstream and the downstream. And wavelength-division multiplexed optical communication. In addition, a new optical network can be configured in which the number of wavelength multiplexes of the entire network is optimally assigned to each line in accordance with a communication request for each line of all terminals, and each transmission capacity of the two types of lines can be arbitrarily changed.

The control of the optical switching unit in the present embodiment is performed by directly providing a control signal from the outside of the concentrator to the optical switching unit, or controlling a part of a loop-type optical signal path or a circuit-switching optical signal path in the concentrator. An optical receiver is provided, a control signal is transmitted from a node connected to the concentrator, the control signal is received by the optical receiver, and the control signal is supplied from the optical receiver to the optical switching unit, or the transmission signal is A control information section may be provided in the section, control information may be read by an optical receiver located on the loop optical path or the circuit-switched optical path, and the optical switching section may be controlled from the optical receiver.

In the present embodiment, the control of the optical switch located between the port of the concentrator and the input / output end of the optical switching unit is controlled by a part of the loop type optical signal path and the switched line type optical signal path in the concentrator. An optical receiver is provided to constantly monitor the usage status of each line, and the line control unit in the concentrator optimally selects the permitted wavelength for each line based on the usage status, and transmits the signal path of each selected wavelength to the optical path. Controlled by a switch, or by providing a control signal directly to the optical switch from outside the concentrator, or providing an optical receiver in a part of the concentrator where the loop type optical signal path and the switched line type optical signal path are common, Sends control signals from the nodes connected to the concentrator,
A control signal is received by the optical receiver, and a control signal is provided from the optical receiver to the line management unit 110, or a control information unit is provided in a part of the transmission signal, so that a loop type optical path or a circuit switching type The control information may be read by an optical receiver located on the optical path, and the optical switch may be controlled from the optical receiver.

In this embodiment, the line management controller 11
0 is located on the loop line between the optical multiplexer 14N and the optical demultiplexer 101, but the arrangement position of the line management control 110 is not limited to this, and may be arranged on a loop line or a switched line. I just need.

In this embodiment, a concentrator using an optical switching unit has been described, but star communication using a star coupler in this part is also possible.

Also, a method has been described in which video data is transmitted on an exchange line and computer information is transmitted on a loop line. However, the type of data transmitted on each line is not fixed.

Further, as a light source and a filter of a used wavelength,
At least one or more variable wavelength light sources and variable wavelength filters may be used in network operation.

In this embodiment, the case where three wavelengths are used has been described. However, the number of multiplexed wavelengths is not limited to this.

(Embodiment 2) FIG. 4 is a view showing a second embodiment of the present invention. FIG. 4 shows an embodiment of the concentrator of the present invention, and FIGS. 2 and 8 show examples of the configuration of an optical communication network using the same. FIG. 5 shows a configuration example of a node suitably used in the optical communication network.
First, each configuration will be described with reference to the drawings.

In FIG. 4, 441, 442,.
Reference numeral 44N designates two wavelengths of a short wavelength band and a long wavelength band with respect to a reference wavelength which can be arbitrarily set by dividing the wavelength multiplexed light input from the input ports 161, 162,... This is a variable optical demultiplexer for demultiplexing into wavelength-division multiplexed light in a band, and control of a reference wavelength divided into two wavelength bands by the variable optical demultiplexer is performed by a line control unit 110. , 451, 452,..., 45N are variable optical demultiplexers 44N, 441, 442,.
4N-1 and a variable optical multiplexer for multiplexing wavelength multiplexed light of each wavelength band transmitted from the optical switching unit. The variable optical multiplexer 4
The output ends of 41, 442,..., 44N are output ports 171, 172,.
, Used as 17N. Further, one output terminal of the variable optical demultiplexer is connected to one input terminal of the variable optical multiplexer located at an adjacent port. That is, in FIG. 4, one output terminal of the variable optical demultiplexer 441 is connected to one input terminal of the variable optical demultiplexer 452, and one output terminal of the variable optical demultiplexer 442 is connected to the variable optical demultiplexer 442. 453 (omitted in FIG. 1) to one input terminal,
Similarly, one output terminal of the variable optical demultiplexer 44N of the Nth port is connected to one input terminal of the variable optical multiplexer 451.

FIG. 5 shows the optical transmitting means and the optical receiving means in the node. Reference numeral 545 denotes a 10 × 10 switch, which switches computer information or video information input from a computer or an external input position to an optical transmitter having a wavelength determined by the line management control unit 110. 546 is a 10 × 10 switch,
The data received by each optical receiver is switched to a computer or an external output device.

Next, the operation of the concentrator of this embodiment and the operation of the optical communication network using the same will be described with reference to FIGS. This network has a loop line and a switched line. As for the optical paths of the loop line and the switched line, for example, the optical signal of the switched line (here, it is assumed that the optical signal is transmitted from the node 231 at the wavelength λ1) is transmitted from the upstream optical fiber 211 to the concentrator 10. Of the variable optical demultiplexer 441 → the optical switching unit 11 (assuming that the wavelength λ is output to the output port 132 of the concentrator 11).
Assume that one optical signal has been delivered. ) → Variable optical multiplexer 45
2 → pass through the downstream optical fiber 222 and enter the node 232 to form a switched line. The optical signal of the loop line (here, it is assumed that an optical signal is transmitted from the node 231 at the wavelength λ10) is sent to the upstream optical fiber 211.
→ Variable optical demultiplexer 441 in concentrator 10 → Variable optical multiplexer 452 → Downstream optical fiber 222 → Node 23
2, is electrically relayed by the node 232, converted again into an optical signal having the wavelength λ10, and transmitted to the optical fiber 212. Similarly, the nodes 232, 234,.
.., Transfer node 238 to form a loop line. In the description of the present embodiment, it is assumed that the number of wavelength multiplexing used in the network is 10, λ1 is the shortest wavelength, and λ10 is the longest wavelength. Also, for convenience of explanation, the output end connected to the optical switching unit of each variable optical demultiplexer and the input end connected to the optical switching unit of the variable optical multiplexer pass wavelength multiplexing in a long wavelength band. The other input / output terminals of the variable optical demultiplexer and the variable optical multiplexer pass wavelength-multiplexed light in a short wavelength band. Each wavelength is used for both loop lines and switched lines. This network usually has a wavelength λ
4, .lambda.5, .lambda.6, .lambda.7, .lambda.8, .lambda., And .lambda.10 are used for switching lines, and wavelengths .lambda.1, .lambda.2, and .lambda.3 are used for loop lines. It is assumed that the wavelength λ1 is assigned to communication conforming to the FDDI protocol. Now, suppose that the time division multiplex communication of the wavelength λ3 of all the wavelengths used for the loop line and the switching line is completed, and the node 231 needs to transmit video information to the nodes 232 and 234.
The node 231 puts on the optical signal of the wavelength λ1 (FDDI line) the use request information of the switching line for transmitting the video information, and transmits the line use request information to the line management control unit 110 in the concentrator. The optical signal of the wavelength λ1 is transmitted on the loop line and input to the line management control unit 110. The line management control unit 110 selects the wavelength λ3 as the switching line use permitted wavelength of the node 231 in response to the request for using the switched line. This is because all wavelengths λ4 to λ10 assigned to the switched line are currently used and the wavelength λ3 of the loop line is used.
Is selected under the condition that is not used. As a result, the available wavelengths on the network (the number of available lines) can be effectively used by utilizing the idle wavelengths of the loop lines. Next, the line management controller 110 controls the optical signal of the wavelength λ1 (FDDI line).
To transmit the information of the selected wavelength λ3 to the node 231. Further, the line management control unit 110 controls the concentrator 1 so that the optical signal path of the wavelength λ3 becomes the line switching type.
The reference wavelength of each variable multiplexer and each variable demultiplexer within 0 is set between λ2 and λ3. Next, the node 231 is 10 × 1
By controlling the 0 switch, video information is input to the optical transmitter 512 having the oscillation wavelength λ3. The optical signal of the wavelength λ3 transmitted from the node 231 is transmitted on the above-described switching line, and is input to the nodes 232 and 234.

Next, it is assumed that the transmission of the video information of the node 231 has been completed and the node 232 needs to transmit the computer information to the node 231. The node 232 transmits the computer information by a time division multiplex communication method using a loop line. The node 232 transmits the use request information of the loop line to the line management control unit 110 in the concentrator. The line management control unit 110 selects the wavelength λ3 as the loop line use permitted wavelength of the node 232 in response to the loop line use request. This means that all wavelengths λ1 and λ2 assigned to the loop line are currently used,
This means that the wavelength λ3 is selected because the wavelength λ3 of the switching line is not used. As a result, the unused wavelength allocated to the switched line can be effectively used.
The line management control unit 110 transmits the information of the selected wavelength to the node 2.
32. The line management control unit 110 sets the reference wavelength of each variable multiplexer and each variable demultiplexer in the concentrator 10 between λ3 and λ4, and sets the wavelengths λ1 to λ3 transmitted from the variable demultiplexers. Is input to the variable optical multiplexer located at the adjacent port, and the variable demultiplexer and the variable multiplexer are controlled so as to form a loop line. Node 232
Controls a 10 × 10 switch to input computer information to an optical transmitter 512 having an oscillation wavelength λ3.
The optical signal of the wavelength λ3 transmitted by the node 231 is transmitted to the above-described loop line and is input to the node 231.

Next, communication of an optical network formed by connecting a plurality of concentrators of the present embodiment in a radial manner will be described with reference to FIG. However, the same operation as the operation of the network using one concentrator and the same operation as in the first embodiment are omitted here. Now, suppose that a communication request of a loop line is generated from the nodes 806 to 803,
Line management control unit 110 (this line management control unit
06 in the concentrator. )
However, an operation of allocating an unused wavelength of λ3 allocated for a switched line to a loop line will be described. The line management control unit 110 notifies the line management control unit 110 and each node in each concentrator on the network that the wavelength of λ3 is newly assigned for the loop line. Each line management control unit 110 sets the reference wavelength of each variable multiplexer and each variable demultiplexer in the concentrator 10 between λ3 and λ4, and transmits the wavelengths λ1 to λ3 transmitted from the variable demultiplexers. Is input to a variable optical multiplexer located at an adjacent port to form a loop line. After that node 8
06 sends out an optical signal of wavelength λ3, and 806 → 813 →
811 → 812 → 801 → 812 → 802 → 812 → 8
An optical signal is transmitted through a loop line path 03.

Next, a switching line communication request is generated from the nodes 806 to 803, and the line management control unit 110 (this line management control unit is in the concentrator 813 connected to the node 806) is connected to the loop line. The operation of allocating the vacant wavelength of λ3 allocated for the switching line to the switching line will be described. The line management control unit 110 notifies the line management control unit 110 in the concentrators 813, 811 and 812 on the network that the wavelength of λ3 is newly assigned for the switched line. The line management control units in the concentrators 813, 811 and 812 set the reference wavelength of each variable multiplexer and each variable duplexer in each concentrator between λ2 and λ3, and are transmitted from the variable duplexers. Optical signals of wavelengths λ3 to λ10 are input to the optical switch 11 and controlled so as to form a switched line. After the switching line type optical path is established, the node 806 sends out the optical signal of the wavelength λ3, and 806 → 813 → 811 → 812 → 801 →
812 → 802 → 812 → 803 along the wavelength λ
3 optical signals are transmitted.

The control of the optical switching unit in this embodiment is performed by directly providing a control signal to the optical switching unit from outside the concentrator, or by controlling a part of a loop-type optical signal path or a circuit-switching optical signal path in the concentrator. An optical receiver is provided, a control signal is transmitted from a node connected to the concentrator, the control signal is received by the optical receiver, and the control signal is supplied from the optical receiver to the optical switching unit, or the transmission signal is A control information section may be provided in the section, control information may be read by an optical receiver located on the loop optical path or the circuit-switched optical path, and the optical switching section may be controlled from the optical receiver.

In this embodiment, the control of the variable multiplexer and the variable demultiplexer located between the port of the concentrator and the input / output terminal of the optical switching unit is performed by controlling the loop type optical signal path and the switching line type in the concentrator. An optical receiver is provided in a part of the optical signal path, and the use status of each line is constantly monitored by the optical receiver, and the line control unit in the concentrator optimizes the use permission wavelength for each line based on the use state. And the signal path of each selected wavelength is controlled by a variable multiplexer and a variable demultiplexer, or a control signal is supplied to the variable multiplexer and a variable demultiplexer directly from outside the concentrator, or An optical receiver is provided in a part where the loop type optical signal path and the switched line type optical signal path are common, and a control signal is sent from a node connected to the concentrator, and the optical receiver Receiving a control signal from the optical receiver and providing a control signal to the line management management unit 110, or providing a control information unit in a part of the transmission signal to provide a control information unit on a loop optical path or a circuit switched optical path. The control information may be read by the located optical receiver, and the variable multiplexer and the variable demultiplexer may be controlled from the optical receiver.

In this embodiment, the line management controller 11
0 is located on the loop line between the variable optical demultiplexer 44N and the variable optical multiplexer 451, but the location of the line management control 110 is not limited to this, and is located on a loop line or a switched line. do it.

The variable demultiplexer and the variable multiplexer described in this embodiment can be realized by changing the incident angle of the dielectric multilayer film of the demultiplexer / demultiplexer using the dielectric multilayer film.

In this embodiment, a concentrator using an optical switching unit has been described, but star communication using a star coupler in this part is also possible.

Also, a method for transmitting video data on a switching line and transmitting computer information on a loop line has been described, but the type of data transmitted on each line is not fixed.

Further, as a light source and a filter of a used wavelength,
At least one or more variable wavelength light sources and variable wavelength filters may be used in network operation.

In this embodiment, the case where the used wavelength is 10 wavelengths has been described. However, the number of multiplexed wavelengths is not limited to this.

(Embodiment 3) FIG. 6 shows a third embodiment of the present invention.
This will be described with reference to FIG. FIG. 6 shows a configuration example of a third embodiment of the concentrator of the present invention.

The basic configuration of the concentrator 10 of this embodiment is almost the same as that of the concentrator 10 of the second embodiment shown in FIG. 4, and the same parts are denoted by the same reference numerals. What is different is that the output end of the wavelength division multiplexed light for the loop line of the variable optical demultiplexer of each port and the variable optical multiplexer of the next-order port (for example, 452 for 441, 451 for 44N, etc.) 1) a loop-wavelength multiplexed optical signal is relayed and amplified between the input end of the loop-wavelength multiplexed light and the first end.
, 62N, and the input terminals 121, 122,... Of the optical switching unit 11.
, 12N and the variable optical demultiplexer 441 connected thereto,
442,..., And 44N relay and amplify the circuit-switched wavelength-division multiplexed light between the output terminals of the wavelength-division multiplexed light for the switched line
, 63N, and the output terminals 131, 132,.
3N and the variable optical multiplexers 651, 65 connected thereto
, 64N are provided between the input ends of the switched-wavelength multiplexed light of 2,..., 65N, and the third repeaters 641, 642,. Is a point. As the first, second, and third repeaters, an optical amplifier that amplifies and repeats an optical signal as it is can be suitably used. In particular,
When wavelength multiplexing is further performed within the above wavelength band, it is preferable to use an optical amplifier as a repeater. It is also possible to use an electric regenerative repeater that converts an optical signal into an electrical signal once, converts it into an optical signal again, and sends it out.

Next, of the operation of the concentrator 10 of the present embodiment, the points that are particularly different from those of the second embodiment will be described. First, by providing the first repeater, it is possible to compensate for the optical loss that the wavelength multiplexed light for the loop line input to the input port of the concentrator 10 receives at the variable optical demultiplexer or the variable optical multiplexer. Thus, the intensity of the optical signal input to the optical receiver of each wavelength multiplexed light for the loop line of the connected node can be increased. Further, by providing the second repeater and the third repeater, the wavelength multiplexed light for the switching line input to the input port of the concentrator 10 can be transmitted to the variable optical demultiplexer, the variable optical multiplexer and the optical switching unit. The received optical loss can be compensated, and the intensity of the optical signal input to the optical receiver for the wavelength multiplexed light for the switching line of the connected node can be increased. In particular, when the number of input / output terminals of the optical switching unit increases, the optical loss increases, which is effective.

In the case where the intensity of the transmitted optical signal of the optical transmitter is sufficiently large, the light receiving sensitivity of the optical receiver is sufficiently large, and the optical loss of the variable optical demultiplexer, the variable optical multiplexer and the optical switching unit is sufficiently small. It is not necessary to provide all of the first, second and third repeaters, and any of them may be deleted. Further, it is not necessary to provide all of the above-described repeaters for each port, and any one of them may be deleted as needed.

Further, the concentrator 10 of the present embodiment
Is preferably used in the optical communication network shown in FIG. 2 and can provide a wavelength division multiplexing composite optical communication network having a margin in optical signal strength.

Also, the concentrator 10 of the present embodiment
Although the configuration is based on the basic configuration of the second embodiment, a configuration based on the basic configuration of the first embodiment is also conceivable.

(Embodiment 4) FIG. 7 shows a fourth embodiment of the present invention.
This will be described with reference to FIG. FIG. 7 shows a configuration example of a fourth embodiment of the concentrator of the present invention.

The basic configuration of the concentrator 10 of this embodiment is almost the same as that of the concentrator 10 of the second embodiment shown in FIG. 4, and the same parts are denoted by the same reference numerals. The difference is that, due to a failure of a node connected to the input / output port or a cut of an optical fiber connecting the concentrator to the node, the wavelength multiplexed light of the loop line output from the output port of the concentrator is paired with this output port. The point is that the concentrator is provided with a countermeasure for a case in which the signal is not input from the input port into the concentrator or the signal deterioration is a problem even if the signal is input. FIG. 7 shows an example of the configuration of a concentrator having this failure countermeasure means. That is, when a failure occurs, the first optical switch is provided at the input end side of the wavelength division multiplexed light of the loop line of the variable optical multiplexer of each port as a means for not distributing the wavelength division multiplexed light for the loop line to that port. 73
, 73N, and a second optical switch 7 at the output end side of the wavelength multiplexed light of the loop line of the variable optical demultiplexer.
, 74N, and repeaters 721, 722,..., 7 which relay and amplify the wavelength multiplexed light of the loop line and the loop line.
2N are provided. When a failure occurs in a terminal or a transmission line, the optical signal of the loop line passes through the first optical switch and the second optical switch of the port where the failure has occurred. The repeater is provided for compensating the loss of the optical signal, and an optical amplifier or an electric regenerative repeater is used. However, when the loss does not matter, the repeater may be deleted.

Next, of the operation of the concentrator 10 of this embodiment, the points that are particularly different from those of the second embodiment will be described. First, when no failure has occurred, for example, the optical signal of a certain wavelength of the loop line input to the concentrator 10 from the input port 161 is output from the variable optical demultiplexer 441 and then the second optical switch 74, is amplified by the repeater 721, passes through the first optical switch 732, is input to the variable optical multiplexer 452, and is output to the output port 172.
Sent from. Then, the signal is received by a node connected to the output port 172 and the input port 162, and after performing necessary processing, is transmitted as an optical signal of the wavelength for the loop line, and is input into the concentrator 10 from the input port 162. As described above, the optical signal having the wavelength for the loop line is output from the variable optical splitter 442, passes through the second optical switch 742, and is input to the repeater 722. The optical signal of the wavelength for the loop line is transmitted in the same manner for the other ports. Next, for example, a failure occurs in a node connected to the output port 172 and the input port 162, or a failure such as disconnection occurs in the connected optical fiber. When no light is input, the output light of the first optical switch 732 is input to the second optical switch 742 and input to the repeater 722. In this way, the interruption of the optical signal due to the above-mentioned obstacle is avoided. Similarly, the interruption of the optical signal due to the failure is avoided for the other ports.

In this embodiment, an example of the configuration of the failure countermeasure means has been described. However, the wavelength division multiplexed light for the loop line input from the input port preceding the port in which the failure has occurred is used.
Any other configuration may be used as long as the output is sent to the output port of the port subsequent to the port in which the failure has occurred.

If a means that does not block the wavelength division multiplexed light for the loop line is provided outside the concentrator, or if a node or optical fiber whose reliability is ensured is connected, the failure of the port will not occur. You can delete the countermeasures.

Although the fault detecting means is omitted in FIG. 7, if necessary, the optical signal is monitored on the path of the wavelength multiplexed light for the loop line input from the input port to detect the fault. What is necessary is just to provide the means which performs.

(Other Embodiments) In each of the above embodiments,
Although the optical demultiplexer and the optical multiplexer are illustrated and described as one element, they may be configured by combining a plurality of element elements. For example, an optical demultiplexer can be configured by combining an optical branching element and an optical wavelength filter.

In the above embodiment, the FDDI and the time division multiplex communication are described as the optical communication system of the loop line. However, the concentrator of the present invention is also effective when the token ring or another loop type optical communication system is used. Can be used for Furthermore, FDD is used for multiple lines that perform loop-type optical communication.
In the present invention, a plurality of loop-type lines combining I, token ring, time division multiplex communication, and the like may be configured.

When a wavelength multiplexing optical communication network is configured using the concentrators described in the above embodiments, when a node performing only loop type optical communication is connected to the concentrator, only a wavelength signal performing switching line type optical communication is used. A means for blocking may be provided in the concentrator, between the concentrator and the node, or in the node. At this time, for example, a wavelength filter that transmits only the wavelength for performing loop-type optical communication without transmitting the wavelength for performing circuit-switched optical communication may be used.

When there is an unused port among the input / output ports of the concentrator described in each of the above embodiments, the optical signal transmitted from the output port for performing the loop type optical communication is not interrupted. Means for inputting the optical signal to the input port may be provided at the input / output port.
As this means, a method of providing a wavelength filter between the input port and the output port for passing only the optical signal for performing the loop type optical communication, or a repeater for regenerating and relaying only the optical signal for performing the loop type optical communication is provided. There is a method of providing between an input port and an output port. As described in the embodiment, a means for bypassing using an optical switch may be provided in the concentrator.

In each of the embodiments described above, a case is described in which a pair of upstream optical fiber and downstream optical fiber is used for the connection between the concentrator and the node and the connection between the concentrators. It can also be converted. For example, the input port and the output port of the concentrator may be integrated using an optical branching / combining device or the like, and the upstream optical signal may be prevented from being input to the downstream transmission system using an optical isolator or the like. At this time, the same means may be provided in the node.

The present invention is not limited to the embodiment described above, and the arrangement position, the number of arrangements, the configuration, the connection relationship, and the like of each component can be arbitrarily and suitably changed.

[0059]

As described above, according to the present invention,
By connecting a node to the concentrator of the present invention using an optical fiber transmission line, the optical fiber transmission line is used as a common transmission line to simultaneously perform loop type optical communication and switched line type optical communication, and also to set the transmission capacity of each line. Can be changed freely to perform effective wavelength division multiplexing communication. Therefore,
A high-performance optical communication network having the advantages of both optical communication systems can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a concentrator according to a first embodiment.

FIG. 2 is a diagram showing a configuration example of an optical communication network using the concentrator of the present invention.

FIG. 3 is a diagram showing a configuration example of a node;

FIG. 4 is a diagram illustrating a configuration example of a concentrator according to a second embodiment.

FIG. 5 is a diagram showing a configuration example of a node;

FIG. 6 is a diagram illustrating a configuration example of a concentrator according to a third embodiment.

FIG. 7 is a diagram illustrating a configuration example of a concentrator according to a fourth embodiment.

FIG. 8 is a diagram showing an example of an extended configuration of the optical communication network of FIG. 2;

FIG. 9 is a diagram showing a configuration example of a conventional optical communication network.

FIG. 10 is a diagram showing a configuration example of a conventional optical communication network.

FIG. 11 is a diagram showing a configuration example of a conventional concentrator.

[Explanation of symbols]

10, 811, 812, 813, 814 Concentrator 11 Star coupler or optical switching unit 121, 122,..., 12N Input terminals 131, 132,..., 13N Optical switching unit output terminals 101, 102, ..., 10N optical demultiplexers 141, 142, ..., 14N optical demultiplexers 91, 92, ..., 9N optical demultiplexers 151, 152, ..., 15N optical demultiplexers 161, 162 ..., 16N concentrator input ports 171, 172, ..., 17N concentrator output ports 231, 232, ..., 238, 801, 802, ...
.., 807 nodes 1111, 1112, 1113, 1121, 1122
1123,..., 11N1, 11N2, 11N3, 1
211, 1212, 1213, 1221, 1222, 1
, 23N, 12N1, 12N2, 12N3 Optical switches 441, 442,..., 44N Variable optical demultiplexers 451, 452,..., 45N Variable optical multiplexers 621, 622,. , 63N Second optical repeaters 641, 642, ..., 64N Third optical repeaters 721, 722, ..., 72N Optical repeaters 731 732 , ..., 73N optical switches 741, 742, ..., 74N optical switches 921, 922, 923, 931 Conventional concentrators 1011, 1012, ..., 1015 Conventional nodes

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H04L 12/44 (56) References JP-A-62-286351 (JP, A) JP-A-1-289340 (JP, A) JP-A-61-137443 (JP, A) JP-A-5-219070 (JP, A) JP-A-6-216910 (JP, A) JP-A-7-38595 (JP, A) JP-A-7-75143 ( JP, A) JP-A-7-107113 (JP, A) Matthew S. J .; Goodman, Multiwavelength Networks and New A proposals to Packet Switching, IEEE Communications MAG AZINE, IEEE, Communications Societies Society. 10, 27-35 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/28-12/46 H04B 10/20

Claims (6)

(57) [Claims] A plurality of ports arranged in a predetermined order;
Separate WDM optical signal input from the port by wavelength
And a part of the entire separated optical signal
Means for sequentially delivering to a plurality of ports in a predetermined order;
At least one other part of the whole separated optical signal
Means for delivering to any port of the
Means for separating the wavelength-division multiplexed optical signal input from the port by wavelength , wherein the means for individually separating the wavelength-division multiplexed optical signal for each wavelength constituting the signal, the separated optical signal is The means for sequentially delivering to a plurality of ports in the predetermined order or the means for arbitrarily selecting and connecting to the means for delivering to the arbitrary port is optional by using a switch for each of the individually separated optical signals. A concentrator characterized in that the concentrator is selected and connected. 2. A plurality of ports arranged in a predetermined order,
Separate WDM optical signal input from the port by wavelength
And a part of the entire separated optical signal
Means for sequentially delivering to a plurality of ports in a predetermined order;
At least one other part of the whole separated optical signal
Means for delivering to any port of the
Means for separating a wavelength-division multiplexed optical signal input from the port by wavelength , wherein the wavelength-division multiplexed optical signal is separated into a wavelength band longer than and shorter than the wavelength with a certain wavelength as a boundary. A means for sequentially delivering the separated optical signals to a plurality of ports in the predetermined order, or a means for arbitrarily selecting and connecting to the means for delivering to the arbitrary port, wherein the wavelength as the boundary is Means for arbitrarily setting the optical signal of one wavelength band separated by the means for connecting the optical signal of one wavelength band to a plurality of ports in order in the predetermined order; and And means for connecting to means for delivering to a port. 3. An optical signal input from the port is relayed,
3. The concentrator according to claim 1, wherein amplifying means is provided at at least one position. 4. The apparatus according to claim 1, further comprising means for not distributing the wavelength multiplexed light arbitrarily selected from the wavelength multiplexed light input from the port to some ports.
4. The concentrator according to any one of claims 1 to 3 . 5. A concentrator according to claim 1 to 4, wherein the optical communication network, characterized in that via an optical fiber transmission line constituted by connecting nodes. 6. comprising a plurality of concentrator of claims 1 to 4, wherein at least two ports of the concentrator, an optical communication network, characterized in that the concentrator or nodes respectively connected.