JPH06350563A - Wavelength multiple network - Google Patents

Abstract

PURPOSE:To quickly restore even an optical fiber fault with simple configuration by easily forming a wavelength multiplex network of a larger scale and allowing the network to easily cope with even a biased traffic demand and using the network for a broad area network. CONSTITUTION:A 3-layer distribution means (routing network) is made up of star coupler 440 and filters 480-482 and the means distributes a received signal and its input output ports are connected by switch circuits 410-412, 480-482. Since the wavelength multiplex network shown in figure is equivalent to a known 3-stage switch circuit, the connection between optional input and output ports is attained. Furthermore, the operating wavelength range of wavelength variable lasers 420-428 is enough to be 1/3 of a conventional range and the network is easily formed totally such that the means is realized by an electric circuit (LSI) when an input output signal is an electric signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal in which a plurality of laser light sources having different oscillation wavelengths on the transmission side are respectively modulated by transmission signals, wavelength-multiplexed on an optical fiber and transmitted, and wavelength-multiplexed on the reception side. The present invention relates to a wavelength division multiplexing network that separates each wavelength for each wavelength, demodulates a transmission signal, and receives it.

[0002]

2. Description of the Related Art FIG. 16 shows a configuration of a wavelength multiplexing network that is the most well known in the past. In the figure, 10
Reference numerals 0 to 108 denote input ports for transmitting electric signals (assuming digital signals), and 110 to 118 have modulating means for modulating optical output by the transmitting electric signals, and a laser light source whose oscillation wavelength is variable (oscillation wavelength of each laser is Different from each other). Also,
Reference numerals 120 to 128 are optical fibers accommodating the optical output from the laser light source, 130 to 132 are wavelength multiplexing circuits for wavelength multiplexing optical signals having different wavelengths input from the respective optical fibers, and 140 to 142 are wavelength multiplexed. An optical fiber that transmits an optical signal. Next, 150 is a 3-input × 3-output star coupler that evenly distributes each wavelength-multiplexed signal that is input to all output optical fibers, and 160 to 162 are output optical fibers of the star coupler. Also, 170 to 172
Is a coupler of 1 input × 3 output, and 180 to 188 are output optical fibers of the couplers 170 to 172, and optical signals from all laser light sources are wavelength-multiplexed. 190-1
Reference numeral 98 denotes a tuner (optical bandpass filter) for extracting light of a specified wavelength from the wavelength-multiplexed optical signal and the extracted optical signal, and demodulates the modulated transmission signal. Receiving circuit having means for
a0 to 1a8 are output ports for receiving electric signals.

As a method of modulating a laser with a transmission electric signal, there are an internal modulation for changing a bias current of the laser itself and an external modulation for installing a modulator outside the laser. As a modulation method, an amplitude modulation, There are frequency modulation, phase modulation, etc., and a corresponding modulator and demodulator is required. These circuit configurations are well known in the art, and since they are not closely related to the essence of the present invention, their detailed configurations are omitted (the same applies to the following embodiments). A wavelength tunable laser is DFB /
It has been well known that a DBR laser, whose oscillation wavelength can be controlled by a bias current or temperature, or a laser whose oscillation wavelength is controlled by changing the central wavelength of an external resonator. Since the types of these wavelength tunable lasers and the wavelength control method are not closely related to the essence of the present invention, their detailed configurations are omitted (the same applies to the following embodiments).

In FIG. 16, an arbitrary input port (any of the input ports 100 to 108) and an arbitrary output port (any of the output ports 1a0 to 1a8) are connected by the principle described below. That is, since the optical output signal of the laser light source corresponding to the connected output port is distributed to all the receiving circuits by the operation of the wavelength multiplexing network in FIG. 16, its oscillation wavelength corresponds to the connected output port. If the wavelength is λj, these input / output ports are automatically connected. As described above, the wavelength division multiplexing network of FIG. 16 does not have a movable part that physically changes the path of the link for connecting the input / output ports, and is composed of a small number of fixed optical fibers and a star coupler. Configured, simply,
The feature is that the line can be set only by changing the oscillation wavelength of the laser light source.

However, the above configuration cannot be applied to a large-scale network because the wavelength variable range of the laser light source increases in proportion to the number of input / output ports and the input optical signal level of the receiving circuit decreases. There was a drawback. FIG. 17 shows a second configuration of a conventional wavelength division multiplexing network that solves the above drawbacks. Reference numerals 200 to 208 denote the input ports in FIG. 16 and the output fibers corresponding to the output fibers 120 to 128 of the laser light source corresponding to the input ports, and the input ports and the laser light sources corresponding thereto are omitted. 210 to 212 are wavelength multiplexing circuits similar to the wavelength multiplexing circuits 130 to 132 shown in FIG.
2 is an output optical fiber of the wavelength multiplexing circuit corresponding to the output optical fibers 140 to 142; and 230 is an optical multiplexer for routing the wavelength-multiplexed optical signal from the input optical fiber to the output optical fibers 240 to 242 corresponding to those wavelengths. Is. Details of the operation of this optical multiplexer will be described later. Reference numerals 250 to 252 denote wavelength demultiplexing circuits for demultiplexing wavelength-multiplexed optical input signals for each wavelength.
Reference numeral 8 is an optical output signal of a single wavelength. A receiving circuit having means for converting the optical output signals 260 to 268 into electric signals and demodulating the modulated transmission signal is required, but is omitted because it is the same as that in FIG.

In order to explain the overall operation of FIG. 17, first, the basic operation of the optical multiplexer 230 will be described with reference to FIG.
Will be described with reference to. The operation of the optical multiplexer 230 is the superposition of the routing of the wavelength-multiplexed signals from the respective input ports, and therefore the operation is shown for each input port. The operation mode 1 shown in FIG. 18A shows how the wavelength-multiplexed optical signal (number of wavelengths = 3) from the input port 220 is routed to the output ports 240 to 242. Optical signal of the input port 220
Is routed to the output port 240 at the same position as the wavelength λ
The optical signals of 2 and λ3 are the 2nd and 3rd output port 2 respectively.
41,242. Next, FIG. 18 (b)
In the operation mode 2 shown in FIG. 2, the wavelength-multiplexed optical signal (number of wavelengths = 3) from the input port 221 is output ports 240 to 2
42 shows how the optical signal of wavelength λ1 is routed to the input port 22 as in the operation mode 1.
The output signal is routed to the output port 241 at the same position as 1, and the optical signal of the wavelength .lambda.2 is routed to the third output port 242 below it. The optical signal of wavelength λ3 is routed to the first output port 240. In this way, the input optical signal has a property of being cyclically routed to the output port with the wavelength λ1 as a reference. The same applies to the operation mode 3 shown in FIG.

Now, the output optical fiber 220 shown in FIG.
Since the optical signals of wavelengths λ1, λ2, and λ3 are multiplexed, the signals ˜222 to ˜222 are distinguished by distinguishing which input port they belong to.
, Λ11, λ12, λ13, the first subscript indicates the input port number, and the second subscript indicates the wavelength type.
From the operation modes shown in FIGS. 18A to 18C, one wavelength is routed from each input port to the output port of the optical multiplexer 230 as shown in FIG.
As a whole, the optical signals of wavelengths λ1, λ2, and λ3 are multiplexed, and are demultiplexed for each wavelength by the wavelength demultiplexing circuits 250 to 252. As a result, in the wavelength division multiplexing network shown in FIG. 17, the wavelength division multiplexing circuits 210 to 212 and the wavelength division circuits 250 to 252 are connected to each other via one wavelength. In this configuration, as shown in FIG. 16, the optical level does not decrease due to the distribution of the optical signal, and the optical signal of the same wavelength is repeatedly used at each input / output port of the optical multiplexer 230. The wavelength tunable range may be small. As a result, there is a feature that the drawback of the conventional wavelength division multiplexing network shown in FIG. 16 can be solved.

[0008]

However, in the conventional wavelength division multiplexing network shown in FIG. 16 described above, it is possible to connect arbitrary input / output ports (hereinafter, this performance is called non-block). In some cases, connection may not be possible with the configuration of the wavelength division multiplexing network shown in FIG. For example, in FIG. 17, input ports 200, 201, 2
When connecting 02 to output ports 260, 261, 262, only one of them is connectable and the other two are not connectable. The input / output ports accommodated in the wavelength multiplexing circuits 210 to 212 and the wavelength demultiplexing circuits 250 to 252 are
Considering that it corresponds to the channels allocated to each region, the wavelength division multiplexing network shown in FIG. 17 is efficient when there is a uniform traffic demand between regions, but it is effective when there is a biased traffic demand. There is a drawback that you cannot do it.

As described above, in the configuration of the two conventional wavelength multiplexing networks shown in FIGS. 16 and 17, the signal level is lowered due to the distribution of the optical signal and the wavelength tunable width of the laser light source is increased in proportion to the number of ports. The first drawback that a large-scale network cannot be constructed due to
It has at least one of the second drawbacks that it cannot meet various traffic demands due to the inability to connect arbitrary input / output ports. Further, the conventional two wavelength multiplexing network configurations shown in FIGS. 16 and 17 have a drawback that if a fiber fails, the service is interrupted for a long time until the failure is restored by repair.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to easily construct a larger-scale wavelength division multiplexing network, easily deal with uneven traffic demands, and to realize a wide area network. It is also intended to provide a wavelength division multiplexing network that can be quickly applied to a failure of an optical fiber with a simple configuration.

[0011]

In order to solve the above-mentioned problems, in the invention according to claim 1, at least one transmitting node accommodating a plurality of input ports and at least one receiving node accommodating a plurality of output ports are provided. In a wavelength multiplexing network configured by connecting a plurality of stations including one station and these transmitting and receiving nodes by an optical fiber network, each of the transmitting nodes is provided with a plurality of input ports and at least the same number of the plurality of input ports. , Each having a laser light source having a different oscillation wavelength, and a first switch means for selectively connecting the plurality of input ports and the laser light source, and each of the receiving nodes, a plurality of output ports, In front of the output port, there is provided a second switch means for selectively guiding the signal input to the receiving node to the output port, and connecting between the transmitting and receiving nodes. Wherein the optical fiber network is a wavelength routing optical fiber network to set the output terminal by the wavelength of the input optical signal.

According to the invention described in claim 2,
In the described wavelength division multiplexing network, the laser light source included in the transmission node is an oscillation wavelength tunable laser whose oscillation wavelength is variable according to a connection request between input / output ports. According to the invention of claim 3,
In the wavelength division multiplexing network described above, the laser light source included in the transmission node is an optical wavelength conversion device that converts the wavelength of an input optical signal into an optical signal of a specified wavelength and outputs the optical signal, and the first switch means is , The optical switch that selectively connects the plurality of input ports to the optical wavelength conversion device, and the second switch means included in the receiving node controls the wavelength of the optical signal input to the receiving node. It is characterized by comprising an optical wavelength conversion device for converting and outputting light of a specified wavelength and an optical space switch for selectively guiding an optical signal output by the optical wavelength conversion device to the output port.

Further, in the invention described in claim 4, in the wavelength multiplexing network according to claim 1, 2, or 3,
The wavelength routing optical fiber network is installed between one or a plurality of optical star couplers, a connection part with a receiving node, and the optical star coupler, and an optical wavelength separating means for transmitting only signal light of a predetermined wavelength. And a plurality of optical fibers connecting the optical star coupler and the optical star coupler and the optical wavelength demultiplexing means. According to the invention of claim 5, in the wavelength multiplexing network of claim 1, 2 or 3, the wavelength routing optical fiber network is 1
One or a plurality of optical multiplexers having different operating wavelength ranges, and an optical fiber for connecting the optical multiplexer to the connection portion with the transmission / reception node.

According to the invention described in claim 6, in the wavelength multiplexing network according to claim 1, 2, 3, 4 or 5, a plurality of the wavelength routing optical fiber networks are provided between the transmitting node and the receiving node. Individually connected, each laser light source of the transmission node and an input terminal of each switch means of the reception node are respectively connected to any one of the plurality of wavelength routing optical fiber networks. Further, in the invention described in claim 7, in the wavelength multiplexing network according to claim 5, two or more of the laser light sources are connected to one input terminal of the optical multiplexer.

Further, in the invention described in claim 8, in the wavelength multiplexing network according to claim 1, 2, 3, 4, 5, 6 or 7, the wavelength routing optical fiber network is:
It has a superposition structure having two or more optical fiber lines,
The transmitting node is one of the superposed optical fiber lines.
It is characterized in that it has a transmitting means for selecting one of them and transmitting an optical signal, and the receiving node has a multiplexing means for multiplexing an input optical signal from the optical fiber line of the superposition structure.

[0016]

According to the first aspect of the present invention, the signals supplied to the plurality of input ports in the transmission node are selectively supplied to any one of the laser light sources by the first switch means. The laser light source outputs an optical signal having its own wavelength to the wavelength routing optical fiber network. On the other hand, in the receiving node, the signal supplied from the wavelength routing optical fiber network is selectively guided to one of the output ports by the second switch means.

Next, according to the invention described in claim 2, the laser light source included in the transmission node in the wavelength multiplexing network according to claim 1 has an oscillation wavelength whose oscillation wavelength is variable according to a connection request between input and output ports. It is a variable laser. According to the invention described in claim 3, the laser light source included in the transmission node in the wavelength multiplexing network according to claim 1 converts the wavelength of the input optical signal into an optical signal of a specified wavelength and outputs the optical signal. As the wavelength conversion device, the first switch means is composed of an optical space switch for selectively connecting the plurality of input ports and the optical wavelength conversion device. Then, the second switching means included in the receiving node converts the wavelength of the optical signal input to the receiving node into light of a specified wavelength and outputs it, and an optical signal output by the optical wavelength converting device. And an optical space switch that selectively guides to the output port.

Next, according to the invention described in claim 4, in the wavelength multiplexing network according to claim 1, 2 or 3, the wavelength routing optical fiber network uses the optical star coupler to transmit the signal supplied from the transmission node. It distributes to the output end to each optical wavelength separation means via an optical fiber. The optical wavelength demultiplexing unit outputs only a specific signal to a predetermined receiving node by transmitting only signal light having a predetermined wavelength. According to the invention of claim 5, claims 1 and 2
Alternatively, in the wavelength multiplexing network described in 3, the wavelength routing optical fiber network outputs the signal supplied from the receiving node to a predetermined output end by a plurality of optical multiplexers. The signal output to the output end is output to the receiving node via the optical fiber.

According to a sixth aspect of the present invention, in the wavelength multiplexing network according to the first, second, third, fourth or fifth aspect, a plurality of signals output from the transmission node are connected to the wavelength routing optical system. By being connected to one of the fiber networks, it is output to a predetermined receiving node. According to the invention described in claim 7, in the wavelength multiplexing network according to claim 5, two or more laser light sources are connected to one input terminal of the optical multiplexer.

According to the invention described in claim 8, in the wavelength division multiplexing network according to claim 1, 2, 3, 4, 5, 6 or 7, the transmission node is configured to transmit by the transmission means.
An optical signal is transmitted by selecting one of the optical fiber lines of a wavelength routing optical fiber network having a superposition structure having optical fiber lines of more than a line. On the other hand, the receiving node multiplexes the input optical signals from the optical fiber lines of the superposition structure by the multiplexing means.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In the figure, 400 to 408 correspond to input ports to the network, and generally time-division multiplexed signals are input, but in the following, it is considered spatially one link. Reference numerals 410 to 412 are switch circuits for connecting the input port and the wavelength tunable laser. 420,
423, 426 and 421, 424, 427 and 422, 4
Reference numerals 25 and 428 are wavelength tunable lasers having the same operating wavelength range but different wavelength routing means shown by the dotted lines connected to them. Also, 430 to
Reference numeral 432 is an optical fiber for accommodating the optical signals output by the wavelength tunable lasers 422, 425, 428, and 440 is a star coupler as a means for evenly distributing the optical signals input thereto. Reference numerals 450 to 452 are output fibers of the star coupler 440 for outputting the wavelength-multiplexed signals, and reference numerals 460 to 462 are filters for fixedly selecting one wavelength from the wavelength-multiplexed signals. Further, 470 to 472 are output signals corresponding to the optical signals of a single wavelength selected by the filters 460 to 462, and 480 to 482 are the outputs of the filters 460 to 462 and the output ports 490 to 498 of the network, respectively. It is a switch circuit to be connected.

In the figure, in the first embodiment, for example, the wavelength tunable lasers 422, 425, 428, the star coupler 440, and the filters 480-482 are, in principle, conventional wavelength multiplexing networks shown in FIG. However, it is characterized in that a plurality of distribution means by a star coupler and a filter are installed on the plurality of surfaces, and the input / output ports thereof are connected by a switch circuit.

The wavelength tunable lasers 422, 425, 4
28, Star coupler 440, Filters 460-462
Can be regarded as logically forming a 3 × 3 space switch. Therefore, the wavelength division multiplexing network shown in FIG. 1 is equivalent to the known three-stage switch circuit. Three
Since the stage switch circuit can connect between arbitrary input / output ports, the wavelength multiplexing network shown in FIG. 1 can connect between arbitrary input / output ports as in the conventional configuration shown in FIG. Comparing the configurations of FIG. 16 and FIG. 1, the number of laser light sources and the number of filters are the same, but in FIG. 1, the operating wavelength range may be 1/3 that of FIG. On the other hand, in FIG. 1, six 3 × 3 switch circuits, which are not necessary in FIG. 16, are required in the input / output port section. Since these switch circuits have a small number of input / output links and can be realized by an electric circuit (LSI) when the input / output signals are electric signals, they can be realized at a small size and at low cost. On the other hand, the conventional configuration requires a wavelength tunable laser with a wide operating wavelength range, which is difficult to manufacture. Therefore, considering comprehensively, the configuration of the wavelength multiplexing network shown in FIG. 1 is easier to realize. It is possible.

Next, a second embodiment of the present invention is shown in FIG. Reference numerals 500 to 507 are input ports to the wavelength division multiplexing network, and 510 to 511 are switch circuits 520, 521 and 52 for connecting the input ports to the wavelength tunable laser.
4, 525 and 522, 523, 526, 527 are wavelength tunable lasers having the same operating wavelength range but different wavelength routing means connected to them. Next, 530, 531, 533, 534 are optical fibers for accommodating the optical signals output by the wavelength tunable lasers 522, 523, 526, 527, and 540 is an equal distribution of the optical signals input to the outputs. It is a star coupler as a means to do. Reference numerals 550 to 551 denote output fibers of a star coupler that outputs a wavelength-multiplexed signal.
Reference numerals 60 to 563 are filters for fixedly selecting one wavelength from the wavelength-multiplexed signals. Also, 570-5
Reference numeral 73 is an output signal (electrical signal) corresponding to the optical signal of a single wavelength selected by the filters 560 to 563, and 580
To 581 are filter outputs and output ports 590 to 597
Is a switch circuit for connecting the.

In the figure, in the second embodiment, for example, the wavelength tunable lasers 522, 523, 526 and 527, the star coupler 540 and the filters 560 to 563 are in principle the same as those of the conventional wavelength multiplexing network of FIG. Although it is equivalent, it is characterized in that it is installed on a plurality of surfaces as in FIG. 1 and that its input / output is connected to the input / output port by a switch circuit. FIG. 2 is the same as FIG. 1 in principle, and has the above-mentioned characteristics as compared with the conventional wavelength multiplexing network. However, the first shown in FIG.
The difference from the embodiment of FIG.
Two wavelength tunable lasers are connected to each of 2, 535, and due to this structure, the number of surfaces of the wavelength routing network may be small. That is, the number of optical fibers connecting the input / output unit and the star coupler may be small. However, since the number of input / output ports on one wavelength routing surface is large, if the wavelength intervals are the same,
The operating wavelength range of the laser is large. That is, in the configuration of the wavelength multiplexing network shown in FIGS. 1 and 2, there is a trade-off relationship between the operating wavelength range of the laser and the number of fibers connected to the input / output unit.

In the wavelength division multiplexing network shown in FIGS. 1 and 2, the wavelength routing network is formed in a star shape and the star coupler 440 or 540 is arranged at the center thereof, but the wavelength routing network is formed in a mesh shape. It is also possible. The third aspect of the present invention constructed according to such a principle
An example of the above is shown in FIG. In FIG. 3, 600 to 607
Is an input port to the network, 610, 611
Is a switch circuit for connecting the input port and the tunable laser. Next, 620, 621, 624, 625
And 622, 623, 626, and 627 are tunable lasers having the same operating wavelength range but different wavelength routing networks connected to them. Also, 6
Reference numerals 30 to 634 are star couplers, reference numerals 640 to 643 are optical fibers connecting the star couplers 630 to 634 in a mesh shape, and reference numerals 650 to 653 are filters for fixedly selecting one wavelength from wavelength-multiplexed signals. 660 and 661 are the output of the filter and the output port 67.
It is a switch circuit for connecting 0 to 677.

The configuration shown in FIG. 3 differs from that of FIG. 2 in the configuration of the wavelength routing network indicated by the dotted line, but it is functionally different from that of FIG.
Is equivalent to That is, in the wavelength division multiplexing network shown in FIG. 3, in place of the large-scale star coupler 540 installed at the center of the star-shaped network shown in FIG. 2, small-scale star couplers 630 to 634 are used as input / output units. The same function is realized by arranging them in a distributed manner.
Since the wavelength routing network shown in FIG. 3 is a mesh network, the number of optical fibers is larger than that of the configuration shown in FIG. 2, but the entire network is characterized by being modularized and distributed. With this configuration,
Similar to FIG. 2, there is a trade-off relationship between the number of optical fibers connecting the transmitting and receiving nodes and the wavelength tunable range of the wavelength tunable laser.

The first to third embodiments shown in FIGS. 1 to 3 are examples in which the same laser having the same operating wavelength range is spatially separated (that is, the optical fiber for receiving an optical signal is divided). Met. On the other hand, FIG. 4 shows the configuration of the fourth embodiment of the present invention in which lasers having the same relative operating wavelength range but different absolute positions on the wavelength axis are used.
It shows in (a). In FIG. 4A, 700 to 707 are input ports to the network, and 710 to 711 are switch circuits for connecting the input ports to the wavelength tunable laser. Then 720, 721, 724, 725 and 72
The wavelength tunable lasers 2, 723, 726, and 727 have the same wavelength tunable width, but have different operating wavelength ranges.
30 to 737 are optical fibers, 740 to 743 are star couplers, 750 to 753 are star couplers 740 to 74.
Optical fiber for connecting 3 in a mesh shape, 760 to 767
Is a filter for fixedly selecting one wavelength from the wavelength-multiplexed signals, and 770 to 771 are filters 7 respectively.
A switch circuit that connects the outputs of 60 to 767 and the output ports 780 to 787. FIG. 4B is a diagram showing an operating wavelength range of the laser, and a range 790 is a wavelength tunable laser 7.
20, 721, 724, 725 operating wavelength range, range 79
Reference numeral 1 is an operating wavelength range of the wavelength tunable lasers 722, 723, 726, 727. The wavelength multiplexing network shown in FIG. 4A has a configuration equivalent to that shown in FIG. 3, and two spatially separated networks indicated by the dotted line in FIG. 3 are realized by one network by wavelength multiplexing. The feature is the point. As a result, in comparison with the configuration shown in FIGS.
It is characterized in that the number of optical fibers required is small.
In the wavelength division multiplexing network shown in FIG. 3, if the number of optical fibers is reduced, the wavelength tunable range of the laser increases, but the configuration shown in FIG. 4A has the advantage that the wavelength tunable range does not increase. However, a wavelength tunable laser having a different operating wavelength range is required, but the oscillation wavelength range of the laser can be easily set by changing the operating temperature, composition, or pitch of grading. On the other hand, FIG.
In the configuration shown in (a), the number of optical signal branches is greater than in FIGS. 1 to 3, so the received optical signal level is low.

In the above-mentioned embodiments, the wavelength routing network having a plurality of surfaces has the same internal configuration in one network, but generally, different configurations are applicable. A fifth embodiment of the present invention based on such a principle is shown in FIG. FIG. 5 is an example in which the above-described principle is applied to the configuration shown in FIG. 1, and two wavelength routing networks having three faces in FIG. 1 are replaced by one wavelength routing network shown in FIG. That is, 800 is a portion corresponding to the wavelength routing network (optical fibers 530 to 534, coupler 540, filters 560 to 563) shown in FIG. 2, and 801 is the wavelength routing network (optical fibers 430 to 432, 450 shown in FIG. -452, coupler 440, filters 460-462). Although not shown, the wavelength routing network 800 may be replaced by the wavelength routing network shown in FIG. 3 (couplers 630 to 634, optical fibers 640 to 643, filters 650 to 653).

As described above, the first to fifth embodiments of the present invention shown in FIGS. 1 to 5 have a wavelength tunable width of the laser without increasing the number of lasers and filters as compared with the conventional FIG. Can be reduced, and the number of distributions can be reduced, so that the received optical signal level is increased. Therefore, the laser emission level can be reduced, and the receiving circuit can be simplified.

Next, by applying the present invention to the conventional structure shown in FIG. 17, another embodiment corresponding to FIGS. 1 to 5 can be obtained. FIG. 6 is a sixth embodiment of the present invention corresponding to FIG.
3 is a block diagram showing the configuration of the embodiment of FIG. In the figure, the portions corresponding to those in FIG. Reference numeral 900 denotes an optical multiplexer corresponding to the optical multiplexer 230 shown in FIG.
Reference numeral 903 denotes an input optical fiber of the optical multiplexer 900, 9
Reference numerals 04 to 906 are output optical fibers of the optical multiplexer 900, and reference numerals 907 to 908 are wavelength routing networks corresponding to the dotted line portions in FIG. That is, the sixth embodiment shown in FIG. 6 can be considered as a modification of the configuration inside the dotted line in FIG. As shown in FIG. 17, the operation of the optical multiplexer 900 is equivalent to a 3 × 3 space switch in which the output port to be routed is determined according to the wavelength of the input optical signal, and logically shown in FIG. It is equivalent to the inside of the dotted line shown. The difference from the inside of the dotted line shown in FIG. 1 is that an optical signal is routed 1: 1 without being distributed to a plurality of output ports. Therefore, in this configuration, FIGS.
Compared with the first to fifth embodiments of the present invention shown in FIG.
There is an advantage that the light level does not decrease due to the distribution of the optical signal. The wavelength tunable range of the wavelength tunable laser is the same as that of the configuration shown in FIGS. 1 to 5, and there is an advantage that the wavelength tunable range may be smaller than that of the conventional configuration of FIG. Further, since it has the non-blocking property, which is a drawback of the conventional configuration of FIG. 17, it is possible to connect arbitrary input / output ports, and it is possible to easily cope with uneven traffic demand.

FIG. 7 is a block diagram showing a configuration of a seventh embodiment of the present invention corresponding to FIG. In the figure,
The parts corresponding to the constituent elements of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. In the seventh embodiment, the wavelength routing network 1000 is different from that of the sixth embodiment shown in FIG. 6, and 1001 to 1003 are wavelength demultiplexing circuits for demultiplexing wavelength-multiplexed optical signals, 1004 to 1004.
An optical signal output 09 has a single wavelength separated by the wavelength separation circuits 1001 to 1003. Reference numerals 1010 to 1015 denote wavelength tunable lasers 522, 523, 526 and 52 shown in FIG.
2 for wavelength tunable lasers 420 to 428
It is a wavelength tunable laser having a double wavelength tunable range. The wavelength separation circuits 1001 to 1003 are the filters 5 shown in FIG.
A combination of individual filters such as 60 to 563 that select only an optical signal of a single wavelength can be used.
In the seventh embodiment, a wavelength separation filter such as a well-known Mach-Zehnder type filter is used. Similar to the configuration shown in FIG. 2, this configuration doubles the wavelength tunable range of the laser, but has the advantage that the number of optical fibers connecting the input and output sections and the number of wavelength routing networks can be reduced by the wavelength multiplexing effect. There is. Further, since it has a non-blocking property which is a drawback of the configuration of the conventional wavelength division multiplexing network shown in FIG. 2, it is possible to connect arbitrary input / output ports and easily respond to uneven traffic demand. Benefits are obtained.

The sixth and seventh embodiments shown in FIGS. 6 and 7 have the same star-shaped net construction as the first and second embodiments shown in FIGS. On the other hand, in contrast to the configurations shown in FIGS. 6 and 7, a configuration principle in which a mesh network configuration is used as shown in FIGS. 3 and 4A can be considered.

FIG. 8 is a block diagram showing the structure of an eighth embodiment having a mesh network structure. In addition,
In the figure, parts corresponding to the constituent elements of the first to seventh embodiments described above are designated by the same reference numerals, and description thereof will be omitted. FIG. 8 shows a configuration in which the portions of the wavelength routing networks 907 to 909 in the configuration shown in FIG. 6 are dispersedly arranged, and they are connected in a mesh by an optical fiber. 11
00 to 1102 is the same 3 × 3 as the optical multiplexer 900.
Optical multiplexers 1103 to 1111 are optical fibers connected in a mesh. Also, 1112
˜1114 are optical couplers for coupling optical signals input from three optical fibers into one optical fiber, 1115 to 1
Reference numeral 117 denotes a wavelength demultiplexing unit that demultiplexes the wavelength-multiplexed optical signal, and the same optical multiplexer as the optical multiplexers 1100 to 1102 can be applied. This is 1 of 3 inputs
It is clear from the operation principle shown in FIGS. 18A to 18C that the circuit operates as a wavelength separation circuit by using only the input of the book.

In FIG. 8, input / output ports 400 to 49
Since the configuration and operation of the part 8 have already been described, the optical multiplexers 1100 to 1102, the optical couplers 1112 to 1114, and the wavelength demultiplexing circuits 1115 to 1117.
The operation will be mainly described. The optical multiplexer 11
The operation principle of 00 to 1102 is shown in FIG.
This is as shown in (c). As an example, consider three tunable wavelength lasers 420, 423, 426. These variable wavelength lasers 420, 423, and 426 are all connected to the uppermost input ports of the optical multiplexers 1100 to 1102, and therefore perform the same wavelength routing operation. That is, the variable wavelength lasers 420, 423, 426.
Are set to the wavelength λ 1, their optical outputs are routed to the optical coupler 1112 through the optical fibers 1103, 1106 and 1109.

According to the operation principle of FIG. 18, the optical fiber 11
It can be understood that the optical signal of wavelength λ1 is routed to 03, 1106, and 1109 only in this case. That is, the variable wavelength lasers 420, 423, 42.
6 can be connected to the output ports 490 to 492 via the wavelength λ1. Similarly, variable wavelength lasers 420, 423,
426 indicates output ports 493 to 495 via the wavelength λ2.
Can be connected to the output port 496 via wavelength λ3
˜498 can be connected. It can be seen that this operation is equivalent to the connection function by the wavelength routing network 907 shown in FIG. That is, the output optical fiber 904 corresponds to the wavelength λ1, the output optical fiber 905 corresponds to the wavelength λ2, and the output optical fiber 906 corresponds to the wavelength λ3. The laser light sources connected to the wavelength routing network 907 are the variable wavelength lasers 422, 425, and 428.
Note that 07, 908, 909 are the same structure. The eighth embodiment has an advantage that the network is modularized and has a decentralized configuration as in the third embodiment shown in FIG. Further, the eighth embodiment is different from the third embodiment shown in FIG. 3 in that there is no distribution of optical signals, and like the sixth and seventh embodiments shown in FIGS. 6 and 7, Since there is no reduction in the optical level of the receiving unit due to distribution, there are advantages that the laser output level may be small and that the receiving circuit is simple. Further, since it has the non-blocking property which is a defect of the conventional configuration of FIG. 17,
It is possible to connect arbitrary input / output ports, and it is possible to easily deal with uneven traffic demand.

Similar to the fifth embodiment shown in FIG. 5, FIG.
In the configuration shown in FIG. 8, the wavelength routing network may have different internal configurations. For this, see Figure 5.
The principle is the same as the above, and it can be realized by arbitrarily combining the dotted line portions (wavelength routing networks) shown in FIGS.
The dotted line portions in FIGS. 6 to 8 have already been shown in the embodiment, and the configuration thereof is clear, so the description thereof will be omitted.

Next, FIG. 9 shows a modification of the transmitting section 1120 shown in FIG. 8 when the number of input ports is large. Here, e1 corresponds to the input ports 400 to 402, is the input port of the transmission node, and 410a is the switch circuit 4
The switch circuits 420a to 422a corresponding to 10 are the same tunable lasers as the tunable lasers 420 to 422. Next, 1100a is the same optical multiplexer as the optical multiplexer 1100, and 420b to 422b are the same tunable lasers as the tunable lasers 420 to 422. Reference numeral 1100b is the same optical multiplexer as the optical multiplexer 1100, and d1 to d3 are two pairs of optical fibers directed to the same receiving node. The configurations and operations of the wavelength tunable lasers 420a to 422a and 420b to 422b and the optical multiplexers 1100a and 1100b are exactly the same as those of the wavelength tunable lasers 420 to 422 and the optical multiplexer 1100. As described above, according to this modification, by installing the laser light source, the optical multiplexer, and the optical fiber in parallel, the number of input ports can be increased although the number of optical fibers is increased. To be

In the eighth embodiment shown in FIG. 8, for example, the input ports 400 to 402 or the output port 4 are used.
Considering that the portion accommodating 90 to 492 corresponds to one node, the number of input / output ports accommodated in one node and the number of nodes included in the network are the same. However, in order to expand the applicable range of the network, it is desirable that the number of input / output ports accommodated in one node and the number of nodes included in the network can be set independently. When the number of input / output ports accommodated in one node is smaller than the number of nodes, it is only necessary to use unnecessary input / output ports in the configurations shown in FIGS. Similarly, when the number of input / output ports accommodated in one node is larger than the number of nodes, a method of preparing a multi-port optical multiplexer and leaving some of the output ports unused can be considered. The configuration principle in that case is shown in FIG.
~ It is equivalent to the configuration principle shown in FIG. However, this method is less efficient because the unused port increases as the difference between the number of nodes and the number of input / output ports accommodated in one node increases. Therefore, FIG. 10 shows the configuration of the ninth embodiment which is based on the configuration shown in FIG. 8 and has the advantage that the number of unused ports does not increase.

The configuration of the ninth embodiment shown in FIG. 10 is as shown in FIG.
Similar to the configuration principle shown in (1), it is based on the principle of sharing one optical fiber by wavelength multiplexing. FIG. 10 shows a configuration on the transmission side, for example, a configuration corresponding to the wavelength tunable lasers 420 to 422 and the optical multiplexer 1100 shown in FIG. In the figure, reference numerals 1200 to 1207 denote output optical fibers of the switch circuit,
Reference numeral 21 is an optical multiplexer having a different operating wavelength range. Next, reference numerals 1208 to 1215 are variable wavelength lasers, and variable wavelength lasers 1208 to 1211 and variable wavelength laser 121 are included.
2 to 1215 are different in operating wavelength range. In this ninth embodiment, one output of optical multiplexers 1220 and 1221 is coupled to output optical fiber 1226 via optical fibers 1222 and 1224, and the other output of optical multiplexers 1220 and 1221 is coupled to optical fiber 12.
It is coupled to the output optical fiber 1227 via 23 and 1225. This is the wavelength tunable laser 4 shown in FIG.
20a to 422a, an optical multiplexer 1100a, tunable lasers 420b to 422b, and an optical multiplexer 1.
Assuming that the operating wavelength range is different from that of 100b, it is configured using a wavelength multiplexing technique, and has a feature that the number of optical fibers can be reduced. Two typical examples of wavelength allocation methods are conceivable. One of them is a concentrated arrangement in which the operating wavelength range of the optical multiplexer 1220 and the operating wavelength range of the optical multiplexer 1221 are concentrated in different wavelength ranges. Yes, the other one is the operating wavelength of the optical multiplexer 1220 and the optical multiplexer 1
221 is a dispersion arrangement in which each wavelength region is dispersed so that the operation wavelengths of 221 are alternately arranged. In addition, in FIG.
Although an example in which two wavelength tunable lasers are connected to one of the input ports of each of the optical multiplexers 1220 and 1221 is shown, the number thereof is generally arbitrary. If limited to the configuration shown in FIG.
~ 1211 and the wavelength tunable lasers 1212 to 1215,
Both are connected to the optical multiplexer 122 after that.
Free Spectral Range of 0,1221
Range, FSR) and above. Here, it is assumed that the number is doubled as an example.

Since the optical multiplexers 1220 and 1221 described above have different operating wavelength ranges, they can be considered as independent elements.
The operation of 0 will be described. Optical multiplexer 1220
If there is one tunable laser connected to one input port of the above, the operation is as shown in the embodiments of FIGS. In FIG. 10, since two wavelength tunable lasers are connected to one input port of the optical multiplexer 1220, the operation can be obtained by superposing the wavelength tunable lasers. In FIG. 10, since each wavelength tunable laser has twice the FSR of the optical multiplexer 1220, the routing operation of the optical multiplexer 1220 is as follows.

For example, when the oscillation wavelength of one of the two wavelength tunable lasers connected to any of the input ports of the optical multiplexer 1220 is λk, the wavelength λk is routed to the output port j of the optical multiplexer 1220. Then, the oscillation wavelength of the other laser is the wavelength λk + F
When the SR or the wavelength λk-FSR is set, the optical output of the wavelength λk + FSR or the wavelength λk-FSR is also routed to the output port j of the optical multiplexer 1220 due to the periodicity of the operation characteristics of the optical multiplexer 1220 on the wavelength axis. It However, since the wavelength λk is different from the wavelength λk + FSR or the wavelength λk−FSR, they can be separated by installing a filter on the receiving side. That is, the ninth embodiment shown in FIG. 10 shows an example in which a small-scale optical multiplexer is wavelength-multiplexed and equivalently applied as a large-scale optical multiplexer. Similarly, two optical multiplexers 1220, 122
No. 1 has a different operating wavelength range, for example, 1.3 μm band and 1.5 μm band, so that it can be wavelength-multiplexed into one fiber as shown in FIG. It is possible to separate the wavelength-multiplexed signal with a filter.

By the way, as described above, two wavelength tunable lasers are connected to one of the input ports of each of the optical multiplexers 1220 and 1221.
Here, in order to simplify the explanation, the wavelength tunable laser 12
Focusing on 08-1211 and the upper half of the optical multiplexer 1220, the size of the optical multiplexer 1220 does not change, but the number of input ports can be increased. As described above, when the wavelengths of the light supplied to the input ports of the optical multiplexer 1220 are λ and λ ± FSR as described above, the lights are all routed to the same output port, but the wavelengths are different. Therefore, it can be separated by the filter inserted in the receiving node. As described above, according to the ninth embodiment shown in FIG. 10, there is an advantage that a node having a large number of input ports can be efficiently realized.

As described above, by applying the optical multiplexer to the transmission node, there is no reduction in the optical signal level due to the distribution of the optical signal, the network has a distributed configuration, the structure can be simplified, and the addition can be easily performed. To be
Modularization of node configuration, number of nodes and 1
The number of input / output ports of one node can be set arbitrarily,
It is possible to connect arbitrary input / output ports, and it is possible to obtain advantages such as being able to easily cope with uneven traffic demand.

As shown in FIGS. 3, 4 and 8, the network connecting the transmitting node and the receiving node in a mesh form has a logical structure, and when applied to an actual network, the node It is possible to take various shapes due to the geographical arrangement of the above and restrictions on the transmission route. Here, the third, fourth, and eighth embodiments shown in FIGS. 3, 4, and 8 will be described in common with the model shown in FIG. 11 (a). In the figure, each of 1300 to 1303 corresponds to, for example, the transmitting node 1120 shown by the dotted line in FIG. 8, and each of 1310 to 1313 corresponds to, for example, the receiving node 1121 shown by the dotted line in FIG. Then 1
Reference numerals 320 to 1323 are input ports accommodated in the respective transmission nodes, and 1324 is an optical fiber group for connecting the transmission nodes 1300 to 1303 and the reception nodes 1310-1313. Reference numerals 1325 to 1328 denote output ports accommodated in each receiving node.

Next, FIG. 11 shows a configuration example when the network of FIG. 11A is applied as an actual network.
It shows in (b). Here, the input / output port and the transmission / reception node are simplified and shown as one link and one node, respectively.
In FIG. 11B, a network in which three stations are connected in a loop is configured. The optical fibers 1324 shown in FIG. 11A for connecting the transmission / reception nodes are collectively housed in the optical fiber cables 1330 to 1332, and the required number of transmission / reception nodes are installed corresponding to the capacity of each station. A part of the optical fiber cable connecting the stations is connected to the node of each station, and the other fibers pass through the station. It can be seen from the connection pattern that the loop-shaped network in FIG. 11B is equivalent to the mesh-shaped network in FIG. 11A. The feature of this configuration is that it can flexibly respond to fluctuations in traffic demand between stations. That is, this network is physically realized by installing a number of transmission / reception nodes corresponding to the traffic demand for each station and connecting them in an optical fiber mesh. The addition and reduction of the transmission / reception nodes can be easily realized by adding or reducing the transmission / reception nodes at the corresponding station and newly connecting or disconnecting the fiber without affecting the existing service system. In this way, given the physical structure of the network, the number of wavelengths corresponding to the required traffic volume is set between one station and another arbitrary station by setting the oscillation wavelength of the tunable laser. The channel can be set easily. Similarly, it is possible to easily change or delete the connection destination of the once set wavelength channel by resetting the oscillation wavelength of the wavelength tunable laser. In the loop-shaped configuration of FIG. 11B, the configuration of each station is the same except for the number of transmission / reception nodes included therein, the number of optical fiber cables between each station is the same, and the overall structure is symmetrical. In addition, since there are two or more routes connecting each station, the number of cores of the optical fiber cable increases, but there is an advantage that detour routing at the time of failure is easily realized.

FIG. 12A is a block diagram showing the configuration of the eleventh embodiment in which the network of FIG. 11A has a physical star configuration. The arrangement of stations and the arrangement of nodes are the same as in FIG. Reference numeral 1400 is a cross-connect node that centrally realizes connection of optical fibers, and 1401 to 1403 are optical fiber cables.
The optical fiber connection in the cross-connect node 1400 requires connection and deletion of a new fiber when a new node is installed or deleted at each station, but is fixed in other cases. This configuration has 1 fiber connection
It is possible to realize it intensively in one place, and there is a feature that the number of cores of the optical fiber cable is small. FIG. 12 (b) shows FIG.
12B is a modification example in which the same network of stations and nodes as in FIG. 12A is linearly arranged.
404 to 1405 correspond to optical fiber cables. With this configuration, the loop-shaped network shown in FIG. 11B is cut at a certain point, and the fiber path is guided under the condition that the fiber path is allowed in only one direction. The number of cores of the optical fiber cable is smaller than that of FIG. 11B, but the number is not the same. Further, as in the case of FIG. 11B, fiber connections are realized by being distributed to each station, and the fiber cross connect node 14 for centrally realizing the connection of optical fibers in FIG.
There is a feature that 00 is not necessary. These eleventh embodiment and its modification have a basic configuration for realizing the network shown in FIG. 11A in consideration of the physical topology. In an actual network, it is possible to realize a configuration in which some of these basic configurations are combined.

FIG. 13A shows a block diagram of a configuration of a twelfth embodiment in which the loop network of FIG. 11B and the linear network of FIG. 12B are combined. Reference numerals 1500 to 1505 are stations each including some transmission / reception nodes, and 1506 to 1511 are optical fiber cables connecting these stations. In FIG. 13A, the three nodes 1503-1505 are the same as those in FIG.
Since the nodes are connected in a loop as shown in FIG. 3 and are symmetrical about the three nodes 1500 to 1502, for example,
Taking the node 1500 as an example, 1500-1503-1
504-1501 and 1500-1503-1505-1
502 is linearly connected as shown in FIG. The number of each optical fiber cable is not shown in order to simplify the explanation, but the required number of core wires is the same as that shown in FIGS. 11 (a), (b) to 12 (a), (b). Easier to ask than the example. As in the twelfth embodiment, by combining the basic configurations shown in FIGS. 11A and 11B to FIGS. 12A and 12B, the optimum network shape in consideration of the station arrangement is obtained. It is possible. Figure 11
(B) -FIG.12 (a), (b) and FIG.15 (a),
FIG. 11 in which all transmitting and receiving nodes are connected in a mesh form
It is equivalent to the configuration of (a), and the number of fibers required for the connection has the property of increasing in proportion to the square of the number of nodes.
For this reason, there is an upper limit to the number of nodes that can be connected in a complete mesh because of the number of cables that can be accommodated and the cost.
As a method of configuring a larger-scale network than the network that can be covered by the configurations illustrated in FIGS. 11B to 13A, a modified example in which a well-known hierarchical method is applied is illustrated in FIG. Shown in b). In the figure, 1
Reference numerals 520 to 1528 are stations each including several transmission / reception nodes, and 1530 to 1541 are optical fiber cables connecting these stations. Transmission / reception node 1520
1522, the transmission / reception nodes 1523-1525, and the transmission / reception nodes 1526-1528 are the loop networks shown in FIG. 11B, and each cover a part of the entire network. Transmission / reception node 152
Reference numerals 2, 1525, and 1528 are stations including the node 1 belonging to the above partial networks, and at the same time, stations including the node 2 forming another loop network connecting the partial networks. The node 1 and the node 2 can be realized by being accommodated in the same system and having different input / output ports. Alternatively, it can be implemented as a separate system,
It is also possible to connect them via a conventional digital cross-connect system or a digital exchange. FIG. 13B shows a configuration example in which a loop-shaped network is hierarchized, but a configuration in which star-shaped (FIG. 12A) and linear (FIG. 12B) networks are combined is also possible. is there. As described above, the configuration of the present invention can be applied not only in the device or in the station but also as a wide area network, and has an advantage of having a wide range of application areas.

In the above description of the first to thirteenth embodiments shown in FIGS. 1 to 13 (a) and (b), it is assumed that the input / output port is an electric signal, and the switch circuit arranged at the transmission / reception node is The laser arranged in the electric circuit or the transmission node is assumed to be a DFB laser or a DBR laser whose oscillation wavelength is variable by an electric signal. Generally, even when the signal of the input / output port is optical, the configuration of the present invention can be applied as it is. For example, consider an optical network in which an input / output signal is assumed to be an optical signal to be wavelength-multiplexed and transmitted, and a certain wavelength of a certain input port is converted into a certain wavelength of a certain output port for output. The conventional optical network based on the configuration shown in FIG. 16 is easily derived as follows. It is assumed that the input ports 100, 101, and 102 shown in FIG. 16 are inputs (optical signals) in which three wavelengths multiplexed in one input port are wavelength-demultiplexed. Tunable laser 110, 11
Reference numerals 1 and 112 denote wavelength conversion elements that convert the wavelength of the input optical signal into a wavelength corresponding to the filter of the output destination. The output light of the wavelength conversion element is selected by corresponding filters (reception circuits) 190 to 198 by wavelength routing and output to the output ports 1a0 to 1a8. Similar to the input ports, these output ports are assumed to be wavelength-multiplexed with, for example, 1a0 to 1a2 in one output fiber. 1a0
An optical network can be constructed by installing a wavelength conversion element after 1a8, converting the input wavelength to a corresponding output wavelength, wavelength-multiplexing the same, and transmitting the result to the optical fiber on the output side. The examples corresponding to FIGS. 2 to 15 under the above-mentioned optical network configuration conditions can be easily obtained.

As an example, FIG. 14 shows a configuration of a thirteenth embodiment of an optical network corresponding to the network shown in FIG.
Shown in. 1600 to 1602 are input optical fibers in which three wavelengths are multiplexed, 1611 to 1613 are wavelength demultiplexing circuits, 1614 to 1616 are wavelength-demultiplexed single-wavelength optical signals, and 1620 to 1622 are, for example, LiNbO.
Optical space switch composed of ₃ switch circuits, 1630
˜1638 are wavelength conversion devices (wavelength conversion lasers) that convert the wavelength of the input optical signal into light of a specified wavelength and output it, 1640 to 1643 are optical multiplexers, 164
4 is an optical fiber connected in a mesh shape, 1650 to 1
Reference numeral 652 denotes a multiplexer for coupling optical signals of different wavelengths input from a plurality of fiber inputs, 1653 to 166.
5 is an optical signal separated into a single wavelength, 1670 to 167
2 is, for example, an optical space switch composed of a LiNbO ₃ switch circuit, 1680 to 1688 are wavelength conversion devices that convert the wavelength of an input optical signal into light of a specified wavelength and output, and 1690 to 1692 are wavelength conversion devices. A wavelength multiplexing circuit for wavelength-multiplexing optical signals output from devices 169
Reference numerals 3 to 1695 are optical fibers for outputting wavelength-multiplexed optical signals.

In the thirteenth embodiment, as shown in FIG.
Similar to the configuration principle of the optical network based on the configuration shown in Figure 5, the wavelength-multiplexed input fiber signal is wavelength-demultiplexed into a single wavelength optical signal input, and the wavelength tunable laser wavelength-tunable wavelength conversion. 11 in that it is replaced with lasers 1630 to 1638, and that wavelength conversion lasers 1680 to 1688 for converting the wavelength of the optical signal output to the output port into the corresponding wavelength on the output fiber are added. Although different from the tenth embodiment, the configuration of the part that realizes the wavelength routing function is the same as that of FIG. As the optical space switch, many configuration methods other than the LiNbO ₃ switch are known, and it is also possible to realize them. In FIG. 14, for example, the wavelength-multiplexed optical signal input from the input optical fiber 1600 is demultiplexed by the wavelength demultiplexing / demultiplexing circuit 1611 and output as a single-wavelength optical signal 1614. These optical signals 1614
Is a wavelength conversion laser 1630 that can be routed to the receiving node of the connection destination by the optical space switch 1620.
~ 1632. Wavelength conversion laser 1
Reference numerals 630 to 1632 convert the input light (having a wavelength of λi) into a designated wavelength λo for routing to the destination receiving node. Wavelength conversion laser 1630-163
2 converts the wavelength, but does not perform any processing on the data signal superimposed on the optical signal of that wavelength. As a result, the input optical signal is wavelength-routed by the optical multiplexer 1640 and is sent to the corresponding receiving node (for example, the receiving node corresponding to the output port 1694 is assumed). λo is multiplexed with an optical signal sent from another transmitting node by a multiplexer 1651 of the receiving node, demultiplexed by a wavelength demultiplexing circuit 1661, and output to one link as an optical signal 1664. The separated optical signal 1664 is wavelength conversion laser (1683 to 1685 of 1683 to 1685) which outputs a corresponding output wavelength by the optical space switch 1671.
Output), and the output is multiplexed by the wavelength multiplexing circuit 1691 and sent to the optical fiber 1694.

The outputs of the wavelength conversion lasers 1683 to 1685 have fixed wavelengths for the respective lasers, but since the wavelength of the input optical signal varies depending on the connection status, a wavelength tunable wavelength conversion laser is required. As described above, even if the input / output signal is light, the basic routing operation is the same as that of the eighth embodiment shown in FIG. The thirteenth embodiment is an example of a configuration in which the input / output signal is optical, but a combination of an input signal being optical and an output signal being electrical is also possible. As described above, the present invention can be applied to an all-optical network, the operating wavelength range of a wavelength conversion device can be reduced, the number of optical signal distributions can be reduced, a distributed network structure can be obtained, and the configuration is simple. There are advantages such as easy addition of nodes. Also, there is an advantage that the applicable range is applicable not only to the interconnection within the device or the station but also to a wide area network.

In the mesh network of the embodiment shown in FIGS. 3, 4A, 8 etc., one fiber is installed between a pair of transmitting and receiving nodes, and a required number of wavelengths are multiplexed and transmitted. To be done. If the fiber fails, communication between the sending and receiving nodes may be unavailable until the failure repair is complete. The invention according to claim 6 of the present invention relates to a method for solving this drawback. In the conventional optical fiber transmission system, with respect to the above-mentioned failure of the optical fiber transmission line, a spare system is installed between the transmitting and receiving nodes with respect to the working system,
We installed switches for switching on both transmitting and receiving nodes,
When the working system fails, a method of simultaneously switching the switches for switching the transmitting and receiving nodes so as to select the spare system is widely adopted. In this conventional method, a switch for switching is required for both the transmitting and receiving nodes, and since the switch for switching is simultaneously switched in the transmitting and receiving node, it becomes necessary to exchange control signals, and control becomes complicated, and There is a drawback that the switching time becomes long. FIG. 15 shows an embodiment of the wavelength multiplexing network of the present invention which can solve these drawbacks.
Shown in.

FIG. 15 is a block diagram showing a fourteenth embodiment in which the present invention is applied to the eighth embodiment shown in FIG. In the figure, the same components as those in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted. The difference from FIG. 11 is that switching switches 1700 to 1702 are added to the output link of the optical multiplexer 1100 (110
1 and 1102 are omitted for simplification), that is, a plurality of fibers (FIG. 15 shows two examples) are connected from the outputs of the changeover switches 1700 to 1702 to connect the transmission / reception nodes. When the plurality of fibers are accommodated in a transmission path, in particular, they are accommodated in different paths in order to ensure reliability against a cable failure. In the receiving node, these fibers are simply multiplexed by the optical couplers 1112 to 1114, and the switch for switching the receiving node is not required unlike the conventional network described above.

In the configuration shown in FIG. 15, attention is paid to fibers 1103 and 1703, for example. Currently fiber 1
It is assumed that an optical signal is transmitted toward 103. It is assumed that the fiber 1103 fails in this situation. The occurrence of a failure is caused by, for example, the wavelength separation circuit 11 on the receiving side.
The output of 15 can be detected by means such as monitoring the light level for each wavelength. In this way, when the failure of the fiber 1103 is detected, the receiving node detects the failure with respect to the transmitting node via, for example, a network for monitoring and controlling provided separately from the network shown in FIG. Send back the information. The transmitting node, which has received the failure detection information from the receiving node, changes the switch 17
00 selects the fiber 1703. As a result, all the optical signals transmitted on the fiber 1103 are transmitted via the fiber 1703. Optical coupler 111
In No. 2, the optical signal from the fiber 1103 or the fiber 1703 is multiplexed regardless of the number of wavelengths to be multiplexed. Therefore, whichever fiber is transmitted, the setting is changed on the receiving node side. Is not necessary at all. As described above, the configuration of the present invention has an advantage that recovery from a transmission line failure can be quickly performed with a simple configuration and control.

The features of the present invention will be generally described above. First, the first feature of the present invention is that a plurality of wavelength tunable laser light sources arranged in a transmission node may have the same set wavelength or have different operating ranges. To meet at least one of the conditions. In the conventional configuration shown in FIG. 16, not only the laser light source included in each transmission node,
The operating wavelengths of all laser sources in the network must be different. This is because assuming that laser light sources of the same wavelength are present, those wavelengths are routed to the same output and are indistinguishable. Further, in the conventional configuration shown in FIG. 17, laser light sources with the same oscillation wavelength can exist in different transmission nodes, but the oscillation wavelengths of the laser light sources must be different within the same transmission node. As described above, in any of the conventional configurations, the presence of laser light sources having the same oscillation wavelength is not allowed in one transmission node. Further, in the conventional configuration, the operating ranges of the respective laser light sources are the same, and laser light sources having different operating ranges are not applied.

A second feature of the present invention is that the transmitting node has a switch circuit for connecting the input port and the laser light source, and the receiving node outputs an output signal and an output obtained by separating the received optical signal for each wavelength. It is to have a switch circuit for connecting to the port. In the conventional configuration, the transmitting node is provided with the wavelength multiplexing means and the receiving node is provided with the wavelength demultiplexing means, but the means corresponding to the switch circuit is not arranged.

The third feature of the present invention is that the wavelength routing means dispersedly arranged in the transmission node is composed of an optical multiplexer or means having an equivalent function. The conventional configuration shown in FIG. 16 does not include an optical multiplexer in the first place, and in the conventional configuration shown in FIG. 17, the optical multiplexers are centrally installed in the central portion of the star-shaped network. The arrangement position is different from the configuration.

A fourth feature of the present invention is that a plurality of optical multiplexers having different operating wavelength ranges are installed in parallel in the distributed arrangement in the transmission node. The conventional configuration shown in FIG. 16 does not include an optical multiplexer in the first place,
Further, in the conventional configuration shown in FIG. 17, the optical multiplexers are centrally installed in the central part of the star-shaped network, and therefore the arrangement position and the number and the conditions to be satisfied by each are different from the configuration of the present invention. .

The fifth feature of the present invention is that a plurality of laser light sources are coupled to one input port of the optical multiplexer distributed in the transmission node. The sixth aspect of the present invention
The feature of is that the transmitting and receiving nodes are connected by a plurality of fibers having different paths, and these fibers are coupled by the receiving node. Furthermore, a seventh feature of the present invention is that one of the transmitting nodes has a wavelength-stabilized laser light source, and its optical output is distributed to other nodes. Means corresponding to the above fifth to seventh characteristics do not exist in the conventional configuration shown in FIGS. 16 and 17.

The eighth feature of the present invention is that the wavelength tunable range of the wavelength tunable element may be small by installing a plurality of wavelength routing optical fiber networks in parallel. Also, by equipping the wavelength routing optical fiber network in parallel, and by equipping the transmitting and receiving nodes with a switch circuit,
The point is that connections between arbitrary ports are possible.

[0062]

As described above, according to the present invention, it is possible to use the same wavelength repeatedly in spatially separated fibers, and it is possible to use light sources operating in different wavelength ranges. Due to this feature, the wavelength tunable range of the wavelength tunable laser light source becomes small, the laser light source can be easily manufactured, and a larger-scale wavelength multiplexing network can be configured. By applying the optical multiplexer as the wavelength routing means, the optical level loss caused by the distribution of the optical signal is eliminated, the emission level condition of the laser light source is relaxed, the receiving circuit is simplified, and a larger-scale wavelength multiplexing network is realized. The advantage is that it can be configured.

Further, in the configuration of the present invention to which the optical multiplexer is applied, since it is non-blocking, it is possible to connect arbitrary input / output ports, and it is possible to easily cope with uneven traffic demand. INDUSTRIAL APPLICABILITY The present invention is applicable to both cases where the input / output signal is electric or optical, and is applicable not only to the connection within the device or the station but also to a wide area network, and has a wide range of application. There are advantages. Further, there is an advantage that an optical fiber failure can be quickly recovered with a simple configuration. It should be noted that the following points are characteristics that can be applied to the conventional configuration, but the rating of the optical signal is realized by setting the wavelength, and the signal format of the transmission data and the modulation method are not affected. As a result, signals of different bit rates and signals of different transmission formats can be connected by a unified process (that is, by wavelength setting), which has the advantage of being able to easily construct a network that integrates various systems. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a fifth exemplary embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a sixth exemplary embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a seventh exemplary embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of an eighth exemplary embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a modified example of the eighth exemplary embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a ninth exemplary embodiment of the present invention.

11 (a) and 11 (b) are block diagrams each showing a configuration of a tenth embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an eleventh exemplary embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of a twelfth exemplary embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a thirteenth embodiment of the present invention.

FIG. 15 is a block diagram showing the structure of a fourteenth embodiment of the present invention.

FIG. 16 is a block diagram showing a configuration of a conventional wavelength division multiplexing network.

FIG. 17 is a block diagram showing another configuration of a conventional wavelength multiplexing network.

18 (a) to (c) are block diagrams for explaining the operation of the optical multiplexer shown in FIG.

[Explanation of symbols]

400 to 408 Input port (plural input ports) 490 to 498 Output port (plural output ports) 420 to 428 Wavelength variable laser (laser light source, oscillation wavelength variable laser) 410 to 412 Switch circuit (first switching means) 480 -482 switch circuit (2nd switch means) 800,801 wavelength routing optical fiber network 1630-1638 (optical wavelength conversion device) 1680-1688 (optical wavelength conversion device) 1620-1625 optical space switch 440,540,630-634 , 740 to 743 Optical star coupler 460 to 462 Filter (optical wavelength separation means) 470 to 472, 550, 551 Optical fiber 900 Optical multiplexer 1120 Transmitter (sending means) 1112 Optical coupler (combining means)

Claims (8)

[Claims] 1. A plurality of stations including at least one transmitting node accommodating a plurality of input ports and a receiving node accommodating a plurality of output ports, and an optical fiber network connecting these transmitting and receiving nodes. In the wavelength division multiplexing network, each of the transmission nodes includes a plurality of input ports, at least the same number of the plurality of input ports, laser light sources having different oscillation wavelengths, and the plurality of input ports and the laser light source. Each of the receiving nodes has a plurality of output ports, and a signal input to the receiving node is selectively output to the output ports before the output ports. And a second switch means for guiding the optical fiber network connecting the transmitting and receiving nodes to set an output terminal according to the wavelength of the input optical signal. Wavelength multiplexing network, which is a quenching optical fiber networks. 2. The laser light source included in the transmission node comprises:
2. The wavelength division multiplexing network according to claim 1, wherein the wavelength division multiplexing laser is an oscillation wavelength tunable laser whose oscillation wavelength is variable according to a connection request between input / output ports. 3. The laser light source included in the transmission node comprises:
An optical wavelength conversion device that converts the wavelength of an input optical signal into an optical signal of a specified wavelength and outputs the optical signal, wherein the first switch means selectively selects the plurality of input ports and the optical wavelength conversion device. And an optical wavelength conversion device that converts the wavelength of the optical signal input to the receiving node into light of a specified wavelength and outputs the optical signal. 2. The wavelength division multiplexing network according to claim 1, further comprising: an optical space switch that selectively guides an optical signal output from the optical wavelength conversion device to the output port. 4. The wavelength routing optical fiber network is installed between one or a plurality of optical star couplers, a connection part with a receiving node and the optical star coupler, and transmits only signal light of a predetermined wavelength. 2. An optical wavelength demultiplexing unit for connecting the transmitting node, the optical star coupler, and a plurality of optical fibers for connecting the optical star coupler and the optical wavelength demultiplexing unit. , 2 or 3 wavelength multiplexing network. 5. The wavelength routing optical fiber network comprises one or a plurality of optical multiplexers having different operating wavelength ranges, and an optical fiber connecting a transmission / reception node connection portion and the optical multiplexer. The wavelength multiplexing network according to claim 1, 2 or 3. 6. Between the transmitting node and the receiving node,
A plurality of the wavelength routing optical fiber networks are connected, and each laser light source of the transmitting node and an input terminal of each switch means of the receiving node are connected to one of the plurality of wavelength routing optical fiber networks. The wavelength multiplexing network according to claim 1, 2, 3, 4 or 5. 7. The wavelength division multiplexing network according to claim 5, wherein two or more of the laser light sources are connected to one input terminal of the optical multiplexer. 8. The wavelength routing optical fiber network comprises:
The optical fiber line has a superposition structure having more than one line, and the transmitting node is one of the superposition optical fiber lines.
2. A transmitting unit for selecting one of the optical signals and transmitting the optical signal, and the receiving node has a multiplexing unit for multiplexing an input optical signal from the optical fiber line of the superposition configuration. The wavelength division multiplexing network according to 2, 3, 4, 5, 6 or 7.