JP3566593B2 - WDM network - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a wavelength that realizes a high-throughput, fault-tolerant network by configuring a hypercube network using a wavelength multiplexing technique and a repetitive wavelength division multiplexing / demultiplexing element (for example, an arrayed waveguide grating filter (AWG)). Regarding multiple networks. In particular, the present invention relates to a network configuration method for easily expanding a large-scale network.
[0002]
[Prior art]
In recent years, with the spread of personal computers and the development of high-speed optical communication technology, the use of networks such as the Internet has been rapidly advancing. In the office, networking of in-house operations is progressing, for example, e-mails are used for office communications. Also, at home, e-mail and the Internet have begun to be used for external contacts, bank balance inquiries, electronic shopping, and the like. As the use of networks in all scenes of life progresses in this way, communication networks are required to have ever-increasing capacities.
[0003]
Communication networks are classified according to the scale such as the number of connection terminals and the connection distance. First, there is a LAN (Local Area Network) as a network for interconnecting computer terminals and the like in a relatively small area such as a building, a factory, an office, or a campus. A network whose network scale has spread to an area such as a region or a city is called a WAN (Wide Area Network) or a MAN (Metropolitan Area Network). Furthermore, wide area networks and the like have been considered as networks for domestic or worldwide use. These networks rarely exist alone, and constitute a huge network interconnected and spread around the world.
[0004]
The communication network includes a plurality of communication nodes and a transmission line connecting the communication nodes. The communication node has a plurality of input / output terminals, and has a switching function for outputting an input signal to a desired output destination. The transmission path secures communication between nodes. In order to speed up the network, it is effective to apply an optical communication system using an optical fiber as a transmission path. By applying an optical communication system using an optical fiber, it has become possible to dramatically increase the transmission capacity and transmission distance as compared with the case where a conventional metal cable is used.
[0005]
Optical communication systems mainly include an optical time division multiplexing communication system (TDM), an optical wavelength multiplexing communication system (WDM), and a spatial multiplexing communication system (SDM) in which optical fibers are multi-core to transmit and receive signals. In the TDM method, a plurality of electric signals are multiplexed on a time axis, converted into a high-speed optical signal, and input to an optical fiber. At the receiving end, the received optical signal is converted into an electric signal, separated into a plurality of original signals, and output. Near-infrared light generally used in the optical communication system is an electromagnetic wave of several hundred terahertz, and it is possible in principle to generate a terahertz-order modulated signal. Optical time division multiplexing communication of several hundred gigabits per second at the laboratory level and 40 gigabits per second at the practical level have already been realized.
[0006]
The WDM method is a method of converting a plurality of electric signals into a plurality of modulated signal lights having different wavelengths from each other and transmitting the modulated signal light through one optical fiber. At the optical receiving end, the signal light is separated for each wavelength using an optical filter, converted into an electric signal, and output. The wavelength division multiplexing communication method has a feature that, compared to the optical time division multiplexing communication method, large-capacity communication is possible even if the signal speed of each modulated signal light is not so large, so that a load on an electric circuit is small. Therefore, a network configuration method based on the wavelength division multiplexing communication system has been actively researched and developed recently.
[0007]
As a network configuration method using the WDM system, a star network configuration using a star coupler has been conventionally proposed.
FIG. 36 shows a configuration example of a conventional wavelength multiplexing network using a star coupler. In the figure, 41-1 to 41-4 are optical transmitters, 42 is a star coupler, 43-1 to 43-4 are optical filters, and 44-1 to 44-4 are optical receivers. The star coupler 42 is an optical element having a function of broadcasting signals input from a plurality of input terminals to all output terminals. The node has an optical transmitter for transmitting different wavelength signal light, and an optical receiver for extracting an arbitrary wavelength signal light by an optical filter and performing photoelectric conversion.
[0008]
In FIG. 36 (a), each optical transmitter sends out signal light of a single wavelength, and each optical receiver takes out signal light of a different wavelength by an optical filter and converts it into an electric signal. FIG. 36B shows a network configuration equivalent to that of FIG. 36A, in which nodes 45-1 to 45-4 having an optical transmitter and an optical receiver are connected in a ring. Thus, a network can be easily formed by using the star coupler and the wavelength multiplexing technique.
[0009]
Here, various variations are considered based on the network configuration of FIG. For example, if an optical transmitter is configured to transmit a signal light of an arbitrary wavelength by using a multi-wavelength light source or the like, and a different receiving wavelength is set for each optical receiver by an optical filter of the optical receiver, an optical transmission is performed. It is possible to transmit a signal from the device to an arbitrary optical receiver. Further, a configuration is also conceivable in which the output signal wavelength of the optical transmitter is fixed so as to be different from each other between the nodes, and the optical filter of the optical receiver is made variable. In this case, the optical receiver can receive an optical signal from any optical transmitter by controlling the variable optical filter.
[0010]
As described above, in a network in which the WDM system and the star coupler are combined, a switching function can be provided by adding a wavelength control element to the optical transmitter or the optical receiver. In these networks using the star coupler and the WDM system, signal transmission and switching are performed at the stage of an optical signal, so that high-speed transmission and high-speed channel switching can be performed. However, in the network configuration based on the star coupler, there is a problem in that the signal power needs to be broadcasted and the restriction on the optical power increases as the number of connection nodes increases.
[0011]
On the other hand, as a network configuration method based on a wavelength division multiplexing communication system that can reduce the constraints on optical power due to signal distribution and increase the number of nodes with a small number of components, an array waveguide diffraction grating type is used instead of a star coupler. Proposals have been made to realize a hypercube network (hereinafter, referred to as “HCN”) known as an efficient network configuration using a filter (hereinafter, referred to as “AWG”).
[0012]
FIG. 37 shows a conventional example in which HCN is realized by combining the WDM method and the AWG. This conventional example has a configuration disclosed in JP-A-8-242208 (Hypercube type interconnection network). FIG. 38 shows a configuration of a hypercube network including eight nodes.
[0013]
In the figure, eight nodes are indicated by addresses 000 to 111 assigned to them. Each of the nodes 000 to 111 has a transmission / reception unit 47, an optical multiplexer 48, and an optical demultiplexer 49. The input / output optical links of the nodes 000 to 111 are sequentially connected to the input / output ports 0 to 7 of the AWG 1. That is, the input port 0 and the output port 0 of the AWG1 are connected to the node 000, and similarly, the node 111 and the input port 7 and the output port 7 of the AWG1 are connected.
[0014]
FIG. 39 shows the relationship between signal wavelengths between input / output ports of the AWG and nodes connected to each input / output port. The 8-input 8-output AWG splits the signal light of wavelengths λ0 to λ7 input to the input port 0 into output ports 0 to 7, and outputs the signal light of wavelengths λ0 to λ7 input to the input port 1 to the output port. The wavelength and the output port are cyclically shifted in the same manner. That is, the input eight wavelengths are output from different output ports, respectively, and the signals from each input port are output from each output port as a wavelength multiplexed signal having different wavelengths. Such a property of the AWG is called looping property, and such an element is generally called a looping wavelength multiplexing / demultiplexing element. In this specification, AWG will be mainly described, but the present invention is not limited to AWG.
[0015]
Here, HCN will be briefly described. HCN is 2 ⁿ A type of network configuration for connecting (n is a positive integer) nodes, where node numbers are represented by binary numbers (the number of nodes is 2 ⁿ (Where n is a positive integer) is an n-bit binary number), and connects nodes in which only one bit of the node number is inverted. For example, in an HCN with eight nodes, the node 000 and the nodes 001, 010, and 100 may be connected, and FIG. 39 shows that the wavelengths used at that time may be set to λ1, λ2, and λ4. That is, as shown in FIG. 37, when an optical signal of wavelengths λ1, λ2, λ4 is input to the input port 0 of the AWG 1 from the node 000, it is demultiplexed to the output ports 1, 2, 4 and the nodes 001, 010, 100, respectively. Is input to The same applies to other nodes (indicated by hatching in FIG. 39). FIG. 38 shows a state where nodes are connected to each other according to such a connection rule. From the figure, it can be seen that the configuration is such that nodes are arranged at the corners of the cube. Incidentally, n is called the order of the HCN, and the HCN composed of eight nodes is called the tertiary HCN.
[0016]
By the way, it has been reported that HCN connecting between nodes by the above rules has various advantages. First, the number of wirings for interconnecting a large number of nodes can be reduced. nth-order HCN (number of nodes N = 2 ⁿ ), The total number of wirings M for realizing M = n2 is M = n2 ⁿ Individual. On the other hand, for example, when N nodes are completely coupled, the total number of wirings T is T = N ² It becomes. Here, since M <T, as the total number of nodes increases, HCN becomes more advantageous in terms of the total number of wires.
[0017]
Next, the average number of hops (the number of nodes that pass through to reach a desired node) can be reduced. Although the maximum number of hops of the HCN is n, for example, in a mesh network, 2√N (N is the total number of nodes), and as the number of nodes increases, the HCN also becomes advantageous.
[0018]
Second is the simplicity of routing and the flexibility of the network. The routing of each node compares the destination node number of the transmitted signal with its own node number, if it is the same, captures it at its own node, and if it is different, the node of its own connected node The node number may be transferred to the node whose bit is inverted as compared with the destination node number. Further, as can be seen from FIG. 38, since there is not one route when performing signal transfer between arbitrary nodes, it is possible to control so that even if some wiring is cut, another route is bypassed. Although each node is connected to a plurality of nodes, the signal transfer throughput can be increased by dividing and transferring the signal of the same destination node to a plurality of wirings.
[0019]
As described above, the HCN has various advantages, and has been mainly applied as a connection network between processors or a processor-memory in a parallel computer. However, applying HCN to an actual network has a problem that wiring becomes complicated.
[0020]
[Problems to be solved by the invention]
In the conventional HCN using the WDM method and the AWG, when the order of the HCN is increased to increase the network scale, the number of input / output ports of the AWG also needs to be increased. However, it is not easy to increase the number of ports of the AWG, and the number of ports that can be realized by the current technology is at most 32 ports. Therefore, only the fifth-order HCN can be realized by the conventional method.
[0021]
Also, Japanese Patent Application Laid-Open No. H8-242208 (Hypercube-type interconnection network) proposes a configuration in which a part of an AWG input / output port is used for expansion in order to secure expandability. Since the number of input / output ports of the AWG is limited as described above, it has been difficult to realize a large-scale HCN. Further, when the number of input / output ports is large, it is difficult to manufacture the AWG, and thus there is a problem that the AWG becomes expensive.
[0022]
SUMMARY OF THE INVENTION An object of the present invention is to provide a wavelength multiplexing network capable of easily and inexpensively increasing the size of a network in an HCN that connects a plurality of nodes with an HCN using the WDM scheme and the AWG.
[0023]
[Means for Solving the Problems]
According to the present invention, in an HCN in which a plurality of nodes are HCN-connected by using the WDM method and the AWG, the network can be enlarged by the following means.
[0024]
To increase the apparent number of input / output ports by arranging optical couplers at the input / output ports of the AWG, and to arrange the numbers, wavelengths, wavelengths, etc. of the nodes connected to each input / output port so as to be HCN-connected. Thus, a large-scale HCN is realized using an AWG having a small number of input / output ports.
[0025]
A large-scale HCN is realized by arranging a signal output AWG and a signal input AWG in a sub HCN composed of a plurality of nodes connected by the HCN and connecting each sub HCN by the WDM method.
[0026]
In the above-described HCN in which the plurality of sub-HCNs are HCN-connected by the WDM method, the HCN connection in the sub-network is also configured by using the AWG and the WDM method by combining the group multiplexer / demultiplexer. Thus, the number of optical fibers input / output from each node can be reduced, and a large-scale HCN can be realized at low cost.
[0027]
In the above HCN in which the plurality of sub HCNs are HCN-connected by the WDM method, a time multiplexing / wavelength multiplexing conversion circuit (TDM / WDM), a wavelength multiplexing / time multiplexing conversion circuit (WDM / TDM) is provided at a signal input / output terminal to the sub HCN. ) Are connected so that the HCN can be expanded recursively. Thereby, a larger-scale HCN is realized.
[0028]
In the above-described HCN in which the plurality of sub-HCNs are HCN-connected by the WDM method, a plurality of input / output lines to the sub-HCN are bundled, and the input / output lines of all the sub-HCNs are gathered at one location, and then the HCN connection is performed. . With such a configuration, the physical HCN connection can be made into a star network close to the configuration of the existing communication network, and the network construction cost including the laying of the optical fiber cable is reduced.
[0029]
By constructing the HCN hierarchically by combining the above-described units, the HCN can be constructed more efficiently.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment: Fourth-order HCN by 8-port AWG)
FIG. 1 shows a first embodiment of the wavelength division multiplexing network of the present invention. In the present embodiment, a case will be described in which a fourth-order HCN (16 nodes) is configured using an 8-port AWG.
[0031]
In the figure, nodes 0000 to 1111 each have a transmission / reception unit, an optical multiplexer, and an optical demultiplexer. The output optical links of the nodes 0000 and 1000 are multiplexed by the optical coupler 2 and connected to the input port 0 of the AWG 1. Similarly, the output optical links of the nodes 0001 to 0111 and the nodes 1001 to 1111 are similarly coupled by the optical coupler 2. And is connected to the input ports 1 to 7 of the AWG 1 in order. Further, the optical coupler 3 is connected to the output ports 0 to 7 of the AWG 1, and one of the two branched input optical links is connected to the nodes 0000 to 0111 in order, and the other input optical link is connected to the nodes 1111 to 1000. Is done.
[0032]
The basic configuration of this embodiment is the same as the conventional HCN shown in FIG. The difference is that the optical couplers 2 and 3 are connected to the input / output ports of the AWG 1 to enable input / output of wavelength multiplexed signal light from two nodes per AWG 1 port. At that time, the node 0000 connects to the input port 0 and the output port 0 of the AWG1, and the node 1000 connects to the input port 0 and the output port 7 of the AWG. Similarly, node 0001 connects to input port 1 and output port 1 of AWG1, and node 1001 connects to input port 1 and output port 6 of AWG1. That is, nodes 0000 to 0111 are sequentially connected to input / output ports 0 to 7 of the same number, while nodes 1000 to 1111 are connected to input ports 0 to 7 in order and output ports 7 to 0 in reverse order. Connecting.
[0033]
Here, a description will be given of a principle that a quaternary HCN (16 nodes) can be configured using an 8-port AWG by such a connection. The 16 nodes 0000 to 1111 are divided into two groups of the most significant bits 0 and 1, and those in which the node number and the AWG input / output port number match for the lower three bits are shown in FIG. FIG. 2 (b) shows an example in which the input port numbers of the AWG match and the output port numbers are connected in reverse order.
[0034]
FIG. 2A shows a case where nodes 0000 to 0111 are connected to input ports 0 to 7 and nodes 0000 to 0111 are connected to output ports 0 to 7. The same input / output relationship as the tertiary HCN shown in FIG. (Indicated by hatching in the figure). The wavelength used between the input and output ports of the HCN connection is the same as in FIG.
[0035]
FIG. 2B shows a configuration in which nodes 1000 to 1111 are connected to input ports 0 to 7 and nodes 1111 to 1000 are connected to output ports 0 to 7. The descending order of the nodes connected to output ports 0 to 7 is as follows. It is opposite to that of FIG. In such an arrangement, the HCN may connect, for example, the node 1000 to the nodes 1001, 1010, and 1100, and the wavelengths used at that time may be set to λ3, λ5, and λ6. The same applies to other nodes (indicated by hatching in the figure). Thus, it is understood that two types of symmetric tertiary HCNs are configured, and two nodes can be simultaneously connected to the input port and the output port, respectively.
[0036]
FIG. 3 shows the connection relationship (1) of the quaternary HCN by the 8-port AWG. This is a combination of FIGS. 2A and 2B, and the wavelength between the input and output ports is omitted. Nodes (0000, 1000) to (0111, 1111) are connected in pairs to input ports 0 to 7 of the AWG, and nodes (0000, 1111) to (0111, 1000) are connected to output ports 0 to 7. Each is connected in pairs. The circles indicate the combinations for HCN connection indicated by hatching in FIG. 2 (a), and the triangles indicate the combinations for HCN connection indicated by hatching in FIG. 2 (b). Also, ● and ▲ indicate that the node shown in FIG. 2 (a) and the node shown in FIG. 2 (b) are connected by HCN.
[0037]
That is, for example, the node 0000 connected to the input port 0 needs to be connected to the nodes 0001, 0010, 0100, and 1000 according to the definition of HCN, and is connected at λ1, λ2, λ4, and λ7, respectively. On the other hand, the nodes 1000 connected to the same input port 0 must be connected to the nodes 0000, 1001, 1010, and 1100 according to the definition of HCN, and are connected at wavelengths λ0, λ6, λ5, and λ3, respectively. This indicates that even when wavelength multiplexed signals from two nodes are multiplexed and input to one port, HCN connection is possible without overlapping wavelengths for connection. . The same can be seen from FIG. 3 for the other input / output ports.
[0038]
Therefore, according to the present embodiment, an optical coupler or the like is connected to the input / output port of the AWG so that a plurality of nodes are connected to each input / output port. By appropriately selecting the signal wavelength of the node, an HCN having a larger number of nodes than the number of ports of the AWG can be realized. That is, in the related art, the 16th port AWG is required for the quaternary HCN (16 nodes), but in the present embodiment, it is possible with the 8 port AWG. Since the AWG becomes difficult and expensive to manufacture as the number of ports increases, if the configuration of the present embodiment is applied, the number of ports of the AWG can be reduced using an inexpensive optical coupler, and HCN can be economically reduced. It can be realized.
[0039]
The relationship between the number of ports of the AWG and the scale of the HCN that can be realized by the number of ports depends on the number of connections L provided by the AWG and the number of connections M for configuring the HCN. Assuming that the number of input ports of the AWG is p (the number of output ports is also the same), the number of connections L provided by the AWG is the number of cells in the table of FIG. 3 and is p × p. On the other hand, the n-th order HCN (the total number of nodes is 2 ⁿ ) The total number of connections M is n × 2 ⁿ It is represented by In principle, an nth-order HCN can be realized only when L ≧ M.
[0040]
For example, in the first embodiment, the number of connections L = 8 × 8 = 64 because an AWG with eight ports is used. On the other hand, the total number of connections of the fourth-order HCN (16 nodes) M = 4 × 2 ⁴ = 64. Therefore, the HCN that can be realized by using the 8-port AWG is up to the fourth order (16 nodes). In this case, L = M = 64, which indicates that all the connections provided by the AWG are used. In FIG. 3, all the cells are used for the HCN connection. It corresponds to that.
[0041]
By the way, in the first embodiment, two nodes are connected to one input port and one output port of the AWG, respectively, but there are restrictions on the combination of the nodes. For example, when the nodes 0000 and 1000 connected to the input port 0 and the nodes 0001 and 1110 connected to the output port 1 are seen, the nodes (0000-0001) having different node numbers by 1 bit between the input and output ports are found. Once connected, a condition is required that the nodes (1000-1110) of each other differ by 2 bits or more. If this condition is applied to all the input / output ports, for example, two nodes connected to the input port are different by one bit, and two nodes connected to the output port are different by four bits (all bits are inverted). That is, when any of the nodes 0001, 0010, 0100, and 1000 is paired with the node 0000 on the input port (output port) side (see FIG. 7B), the output port (input port) side Only the node 1111 is paired with the node 0000.
[0042]
However, there is a degree of freedom in the connection relationship between the input / output ports of the AWG and the nodes, that is, the arrangement of the nodes for the input / output ports. Hereinafter, this will be described. The array of nodes connected to the input / output ports 0 to 7 shown in FIG. In addition, the pattern A of the input port and the pattern A of the output port are a combination as described above and are not the same. AA indicates a pattern (HCN pattern) of ○, ●, △, ▲ indicating the HCN connection by the input port pattern A and the output port pattern A. Now, patterns A ′, B, and B ′ are defined as follows as another example of the node array.
[0043]
Pattern A ': Pattern A in which the array is inverted in units of 4 ports
Pattern B: Pattern A in which the array is inverted every two ports
Pattern B ': Pattern B in which the array is inverted in units of 4 ports (Pattern A' in which the array is inverted in units of 2 ports)
FIG. 4 shows the connection relation (2) of the quaternary HCN by the 8-port AWG. This is an output port of pattern A '. This HCN pattern is called AA '. FIG. 5 shows the connection relationship (3) of the quaternary HCN by the 8-port AWG. This is an output port of pattern B. This HCN pattern is called AB. FIG. 6 shows the connection relationship (4) of the quaternary HCN by the 8-port AWG. This is an output port of pattern B '. This HCN pattern is called AB '. 4 to 6, ，, ●, Δ, and ▲ are based on the same notation as in FIG. Further, even if the arrangement of the nodes connected to the input ports is changed to a pattern other than the pattern A, the HCN pattern can be similarly formed.
[0044]
Further, the pattern of the input / output ports is not limited to the above four patterns, and the arrangement may be changed at random. Here, FIG. 7A shows the connection relationship of the fourth-order HCN when the pattern A of the input port and the pattern A of the output port shown in FIG. 3 are shifted by one each. FIG. 7B shows the connection relationship of the quaternary HCN when the combination of the two nodes connected to the input port is changed.
[0045]
(Fifth-order HCN with 16-port AWG)
A case where a fifth-order HCN (32 nodes) is configured by a 16-port AWG using the four patterns defined above will be described. The node number of the 32 nodes is 0000 to 11111 in 5 bits, but here, the upper 1 bit and the lower 4 bits are considered separately. Further, the 16 input / output ports are divided into two blocks 1 and 2 of 0 to 7 and 8 to 15 respectively, and one of patterns A, A ', B and B' is assigned to each.
[0046]
FIG. 8 shows the connection relationship (1) of the fifth-order HCN by the 16-port AWG. Here, upper 1 bits 0 and 1 are allocated to blocks 1 and 2 of the input port, and pattern A is allocated to the lower 4 bits. Also, upper 1 bits 0 and 1 are assigned to output port blocks 1 and 2, and pattern A is assigned to the lower 4 bits.
[0047]
At this time, in the block 1 of the input port and the block 1 of the output port, and in the block 2 of the input port and the block 2 of the output port, the upper one bit is equal to each other. Thus, the HCN pattern AA is formed. On the other hand, in the block 1 of the input port and the block 2 of the output port, and in the block 2 of the input port and the block 1 of the output port, the upper 1 bit is different. Thus, HCN connection is established. This HCN pattern is called AA.
[0048]
FIG. 9 shows the connection relationship (2) of the fifth-order HCN by the 16-port AWG. Here, upper 1 bits 0 and 1 are allocated to input port blocks 1 and 2, and pattern A is allocated to the lower 4 bits. Also, upper 1 bits 0 and 1 are allocated to output port blocks 1 and 2, and patterns A and A 'are allocated to lower 4 bits, respectively.
[0049]
At this time, the HCN pattern AA is formed in the block 1 of the input port and the block 1 of the output port, and the HCN pattern AA ′ is formed in the block 2 of the input port and the block 2 of the output port. On the other hand, an HCN pattern AA ′ is formed in the input port block 1 and the output port block 2, and an HCN pattern AA is formed in the input port block 2 and the output port block 1.
[0050]
FIG. 10 shows the connection relationship (3) of the fifth-order HCN by the 16-port AWG. Here, upper 1 bits 0 and 1 are allocated to blocks 1 and 2 of the input port, and pattern A is allocated to the lower 4 bits. Also, upper 1 bits 0 and 1 are allocated to output port blocks 1 and 2, and patterns B and B 'are allocated to lower 4 bits, respectively.
[0051]
At this time, the HCN pattern AB is formed in the block 1 of the input port and the block 1 of the output port, and the HCN pattern AB ′ is formed in the block 2 of the input port and the block 2 of the output port. On the other hand, the HCN pattern AB ′ is formed in the block 1 of the input port and the block 2 of the output port, and the HCN pattern AB is formed in the block 2 of the input port and the block 1 of the output port.
[0052]
In this way, the input / output ports 0 to 15 are divided into two blocks of eight each, and the patterns A, A ′, B, B ′ or other patterns are assigned to each of them. (32 nodes). In FIGS. 8 to 10, the pattern A is assigned to each of the two blocks of the input port. However, the fifth order HCN can be similarly configured by assigning other patterns.
[0053]
FIG. 11 shows the connection relationship (4) of the fifth-order HCN by the 16-port AWG. Here, pairs of nodes 0000 to 01111 and nodes 1000 to 11111 are connected to input ports 0 to 15, respectively, and nodes 0000 to 01111 and nodes 11111 to 10000 are paired to output ports 0 to 15, respectively. . This is an extension of the configuration of the quaternary HCN using the 8-port AWG in FIG. 3 to the quintic HCN using the 16-port AWG. This concept can be sequentially extended to a 6th-order HCN using a 32-port AWG, a 7th-order HCN using a 64-port AWG, etc. However, in the following description, the configuration method is omitted, and A configuration method based on this block pattern will be described. ○, 表 記, △ in FIG. 11 are based on the same notation as in FIG. As for the 16-port AWG, [lambda] 0 to [lambda] 15 are cyclically allocated between the input and output ports, and the corresponding wavelength is selected for HCN connection.
[0054]
Note that the fifth-order HCN (32 nodes) by the 16-port AWG has the number of AWG connections L = 16 × 16 = 256 and the number of connections of the fifth-order HCN M = 5 × 2 ⁵ = 128, and the relationship of L> M is satisfied, so that HCN is realized. Incidentally, the sixth-order HCN (the number of nodes 64) is M = 384, which is larger than L, and is not feasible.
[0055]
(Sixth-order HCN with 32-port AWG)
A case where a sixth-order HCN (64 nodes) is configured by a 32-port AWG using the pattern defined above will be described. The node number of the 64 nodes is 6 bits from 000000 to 111111. Here, the upper 2 bits and the lower 4 bits are considered separately. Further, 32 input / output ports are divided into four blocks 1 to 4 of 0 to 7, 8 to 15, 16 to 23, and 24 to 31, and any one of patterns A, A ', B, and B' assign.
[0056]
FIG. 12 shows a connection relationship (1) of a sixth-order HCN by a 32-port AWG. Here, upper two bits 00 to 11 are allocated to input port blocks 1 to 4 and a pattern A is allocated to lower four bits. Also, upper two bits 00 to 11 are assigned to the output port blocks 1 to 4, and patterns A, A ', B, and B' are assigned to the lower four bits, respectively. At this time, HCN patterns AA, AA ′, AB, AB ′ are formed between blocks having the same upper two bits. On the other hand, HCN patterns AA ′, AB, AA, and AB ′ are formed between blocks in which one bit is different from the upper two bits.
[0057]
FIG. 13 shows a connection relationship (2) of a sixth-order HCN by a 32-port AWG. Here, upper two bits 00 to 11 are allocated to the input port blocks 1 to 4 and a pattern A ′ is allocated to the lower four bits. The upper two bits 11 to 00 are allocated to the output port blocks 1 to 4 and the patterns B ′, B, A ′, and A are allocated to the lower four bits (both the upper two bits and the lower four bits are reversed in FIG. 12). . At this time, HCN patterns A'A, A'A ', A'B, A'B' are formed between blocks having the same upper two bits. On the other hand, HCN patterns A'-A ', A'-B, A'-A, and A'-B' are formed between blocks in which one bit is different from the upper two bits.
[0058]
In the sixth-order HCN based on the 32-port AWG, the combination of the upper 2 bits 00 to 11 and the lower 4 bits can be arbitrarily combined in block units, and the patterns A, A ', B, It is not limited to B '.
[0059]
Here, the HCN patterns AA, AA ', AB, AB', A'A, A'A ', A'B, A'B', AA, AA ', AB, A shown above. -B ', A'-A', A'-B, A'-A, and A'-B 'are shown in FIG. As can be seen from the definitions of the patterns A, A ', B, and B', for example, the HCN patterns AA and A'A 'are the same pattern, and the other HCN patterns have the same pattern as shown in FIG.
[0060]
FIGS. 15A and 15B show the connections and the HCN patterns of FIGS. 12 and 13 arranged based on the above relationship. Here, at the hatched portions, the upper two bits are equal between the input / output ports, and those different by one bit from the lower four bits are connected to each other, and the HCN patterns AA (A'A '), AA'(A'A) , AB (A'B '), or AB'(A'B). Also, at the point where one of the upper two bits is different and the lower four bits are equal between the input / output ports, the HCN patterns AA (A'-A ') and AA' (A ' -A), AB (A'-B '), or AB'(A'-B).
[0061]
By combining these, a 7th-order HCN (128 nodes) can be formed by a 32-port AWG, as in the case of forming a 4th-order HCN by an 8-port AWG shown in FIG. The node number of the 128 nodes is 00000000-1111111 of 7 bits. Here, the upper 3 bits and the lower 4 bits are considered. Further, 32 input / output ports are divided into four blocks 1 to 4, 0 to 7, 8 to 15, 16 to 23, and 24 to 31, and one of patterns A, A ', B, and B' is assigned to each. .
[0062]
(7th-order HCN with 32-port AWG)
FIG. 16 shows the connection relationship (1) of the seventh-order HCN by the 32-port AWG. Here, upper three bits 000 to 011 are first allocated to blocks 1 to 4 of the input port in order, and at the same time, upper three bits forming a group are determined to 100 to 111 according to the following conditions. Assign A '. First, upper 3 bits 000 to 011 are sequentially allocated to the output port blocks 1 to 4, and at the same time, upper 3 bits 100 to 111 to form a set are determined according to the following conditions. ', B, B' are assigned. That is, four nodes are connected to the optical couplers connected to the respective input / output ports of the AWG.
[0063]
FIG. 17 shows the connection relationship (2) of the seventh-order HCN by the 32-port AWG. The difference from FIG. 16 is that the pattern arrangement (combination) of the lower 4 bits of the node number connected to the output port of each block is different. FIG. 18 shows the connection relationship (3) of the seventh-order HCN by the 32-port AWG. The difference from FIG. 16 is that the arrangement (combination) of the upper 3 bits of the node number connected to the output port of each block is different. Here, first, the upper three bits 000,001,100,101 are sequentially allocated to the output port blocks 1-4, and at the same time, the upper three bits, 011,010,111,110, which form a set, respectively, are determined according to the following conditions. Further, patterns A, A ', B and B' are assigned as lower 4 bits.
[0064]
Here, the conditions 1 to 4 of the combination of the upper 3 bits and the lower 4 bits of the node number connected to the input / output port will be specifically described with reference to the examples of FIGS.
[0065]
Condition 1 is that a node number connected to an input / output port of each block is a combination of two different upper two bits. For example, 101 is assigned to 000 for block 1 of the input port, and 100 is assigned to 001 for block 2 of the input port.
[0066]
Condition 2 is that when the node numbers connected to the input / output ports of each block correspond to each other, at the hatched portions in FIGS. Assign so that it becomes a combination. For example, as shown in FIG. 19, when 000 and 101 are paired in block 1 of the input port, 110 or 011 is paired with 000 in block 1 of the output port. 16 and 17 employ the combination of FIG. 19A, and FIG. 18 employs the combination of FIG. 19B.
[0067]
Condition 3 is a combination in which, when the node numbers connected to the input / output ports of each block are associated with each other, the upper three bits have three 1-bit differences between the upper three bits at the locations not hatched in FIGS. To assign. For example, as shown in FIG. 20, when 000 and 101 are paired in block 1 of the input port, 111 or 010 is paired with 001 in block 2 of the output port. 16 and 17 employ the combination of FIG. 20 (a), and FIG. 18 employs the combination of FIG. 20 (b).
[0068]
Condition 4 is that, when the node numbers connected to the input / output ports of each block are associated with each other, the lower 4 bits of the upper 3 bits are different from the lower 3 bits by 1 bit at locations not hatched in FIGS. HCN patterns are assigned so as to be different from each other. For example, assuming that the lower 4 bits corresponding to the upper 3 bits 000 and 101 in the block 1 of the input port in FIG. 16 are patterns A and A ′, the lower 4 bits corresponding to the upper 3 bits 001 and 111 in the block 2 of the output port. Are patterns A ′ and B. Thereby, mutually different HCN patterns AA ', A'-A', and A'-B are formed in three sets (000-001, 101-001, 101-111) in which the upper three bits differ by one bit. Is done.
[0069]
In the portions not hatched in FIGS. 16 to 18, the four HCN patterns AA (A′-A ′), AA ′ (A′-A), and AB (A′-B) shown in FIG. ') And AB'(A'-B), which are different from each other. FIG. 21 shows the HCN pattern.
[0070]
Here, in FIG. 16, four node numbers connected to each input / output port of the 32-port AWG are shown in FIG. 22, and HCN patterns indicated by ○, ●, Δ, ▲, Δ are shown in FIG. The location of this mark indicates the position of the input / output port for HCN connection, and the corresponding wavelength is determined.
[0071]
Note that the HCN connection relationship shown in FIGS. 16 to 18 is an example, and when the above conditions 1 to 4 are satisfied, the combination and arrangement of the upper 3 bits and lower 4 bits of the node number connected to the input / output port are It can be arbitrarily selected.
[0072]
Further, the sixth-order HCN (64 nodes) based on the 32-port AWG has the number of AWG connections L = 32 × 32 = 1024, and the number of sixth-order HCN connections M = 6 × 2 ⁶ = 384. Number of 7th-order HCN (128 node) connections M = 7 × 2 ⁷ = 896. Therefore, since both satisfy the relationship of L> M, the 6th-order HCN and the 7th-order HCN are realized by the 32-port AWG as described above.
[0073]
As described above, in contrast to the conventional tertiary HCN (8 nodes) based on the 8-port AWG and the quaternary HCN (16 nodes) based on the 16-port AWG, the present invention uses the 4-port AWG and the 4 × 1 × 2 optical coupler. Next-order HCN (16 nodes), 5th-order HCN (32 nodes) with 16-port AWG and 1 × 2 optical coupler, 6th-order HCN (64 nodes) with 32 port AWG and 1 × 2 optical coupler, 32 port AWG 7th order HCN (128 nodes) by 1 × 4 optical coupler is possible. That is, a large-scale primary or secondary HCN can be realized using an AWG with a small number of ports and an inexpensive optical coupler. Similarly, an 8th-order HCN (256 nodes) using a 64-port AWG and 1 × 4 optical coupler, a 9th-order HCN (512 nodes) using a 128-port AWG and 1 × 4 optical coupler, and a 128-port AWG and 1 × It can be expanded sequentially, such as a 10th-order HCN (1024 nodes) using eight optical couplers.
[0074]
(Second embodiment)
FIG. 24 shows a second embodiment of the wavelength division multiplexing network of the present invention. In the present embodiment, a case will be described in which a secondary HCN having four nodes is set as a sub HCN and four sub HCNs are connected to form a fourth HCN (16 nodes).
[0075]
In the figure, sub HCNs 00 to 11 respectively contain nodes 0000 to 0011, nodes 0100 to 0111, nodes 1000 to 1011, and nodes 1100 to 1111. HCN connections are established between the nodes. For example, in the sub HCN00, the nodes 0000-0001, 0000-0010, 0001-0011, and 0010-0011 are bidirectionally connected. It should be noted that the type of interconnection when implementing sub HCN is not particularly mentioned.
[0076]
Each node includes an optical transmission unit that multiplexes a plurality of wavelength signal lights and outputs the multiplexed signal light, and an optical reception unit that splits and receives the input wavelength multiplex signal light. On the other hand, a signal output AWG 5 and a signal input AWG 6 are connected to each sub HCN as an interface to an external network. A corresponding input port of the signal output AWG 5 and a corresponding output port of the signal input AWG 6 are connected to the optical transmission unit and the optical reception unit of each node. Each node uses the same port number of the signal output AWG5 and the signal input AWG6. For example, the input port 0 of the signal output AWG 5 and the output port 0 of the signal input AWG 6 are connected to the node 0000.
[0077]
Each of the sub HCNs 00 to 11 is HCN-connected via a signal output AWG 5 and a signal input AWG 6. That is, the sub HCNs 00-01, 00-10, 01-11, and 10-11 are bidirectionally connected. However, the connection of each sub HCN uses the same port number of the signal output AWG 5 and the signal input AWG 6. For example, when connecting the sub HCN 00 and the sub HCN 01, the output port 0 of the signal output AWG 5 and the input port 0 of the signal input AWG 6 are connected. FIG. 25 shows the relationship between the input / output ports of the signal output AWG 5 and the signal input AWG 6 and the input / output wavelength.
[0078]
Here, in the HCN connection across the sub HCN, for example, the node 0000 of the sub HCN 00 is connected to the node 0100 of the sub HCN 01 and the node 1000 of the sub HCN 10. At this time, according to the relationship shown in FIG. 25, connection is possible by transmitting signal light of wavelengths λ0 and λ1 from the node 0000. The signal light of wavelength λ0 transmitted from the node 0000 is input to the input port 0 of the signal output AWG 5 of the sub HCN00, and output from the output port 0. Since the output port 0 of the signal output AWG 5 is connected to the input port 0 of the signal input AWG 6 of the sub HCN 01, the signal light of the wavelength λ0 is input from the output port 0 of the signal input AWG 6 to the node 0100. You. Similarly, the signal light of wavelength λ1 transmitted from the node 0000 passes through the signal output AWG 5 of the sub HCN 00 and the signal input AWG 6 of the sub HCN 10 and is input to the node 1000.
[0079]
Similarly, by appropriately selecting the wavelength of the input / output signal light of each node, all nodes can be HCN-connected. That is, by connecting the four secondary HCNs (the number of nodes is 4) to the HCN via the AWG, a fourth-order HCN (16 nodes) is realized.
[0080]
According to this configuration, it is possible to extend the order of the HCN by the number of ports of the signal input / output AWG of the sub HCN. In the case of FIG. 24, there are four AWGs for signal input / output, and by connecting 16 sub HCNs using these four ports as shown in FIG. 26, a maximum of 6th order HCN (64 nodes) It can be extended to: In FIG. 26, reference numeral 9 denotes sub HCNs, and each sub HCN is connected via a connection line.
[0081]
As described above, according to the present embodiment, in order to connect the sub HCNs connected to the HCN, each node is provided with a transmission / reception unit for a wavelength multiplexed signal, and the sub HCN has a signal output AWG5 and a signal input AWG6. And by connecting a plurality of sub-HCNs by HCN using these two AWGs, the order of the HCN or the number of nodes can be easily expanded.
[0082]
(Third embodiment)
FIG. 27 shows a third embodiment of the wavelength division multiplexing network of the present invention. In this embodiment, the wiring in the sub HCN of the second embodiment shown in FIG. 24 is realized by using the WDM system and the AWG, and furthermore, the wavelength of input / output between nodes in the sub HCN and the input / output between sub HCNs A configuration will be described in which the signal wavelength input / output lines from each node are divided into one by using a group multiplexer / demultiplexer that divides the wavelength band to be used and multiplexes / demultiplexes for each band.
[0083]
In the figure, sub HCNs 00 and 01 accommodate nodes 0000 to 0111 and nodes 1000 to 1111 respectively, and each node is HCN-connected via an 8-port AWG1. The tertiary HCN using the 8-port AWG can be handled by the conventional HCN shown in FIG.
[0084]
Each node includes an optical transmitter for multiplexing and outputting a plurality of wavelength signal lights, and an optical receiver for demultiplexing and receiving the input wavelength-multiplexed signal light. On the other hand, a signal output AWG 5 and a signal input AWG 6 are connected to each sub HCN as an interface to an external network. The corresponding input ports of the AWG 1 and the signal output AWG 5 are connected to the optical transmission unit of each node via the group splitter 7, and the AWG 1 is connected to the optical reception unit of each node via the group multiplexer 8. And the corresponding output port of the signal input AWG 6 are connected.
[0085]
FIG. 28 shows the function of the group branching filter 7. Since the group multiplexer 8 is reversible to the group multiplexer 7, the function of the group multiplexer 7 will be described here. The group splitter 7a shown in FIG. 28 (a) sets the wavelength band used for the signal light for connecting the HCN inside the sub HCN to the shorter wavelength side of λ0 to λp−1, and the signal for connecting the sub HCNs. It is applied to a configuration in which the wavelength band used for light is on the long wavelength side of λp to λq. The operation of the group splitter 7a is such that the input wavelength multiplexed signal light is split into a wavelength band for connection within the sub-HCN and a wavelength band for connection between the sub-HCNs and output. Such a function is, for example, to split the input wavelength multiplexed signal light into two using an optical coupler or the like, connect a high-pass optical filter that passes only the short wavelength band to one output, and connect the other output to the other output. This can be realized by connecting a low-pass optical filter that passes only the wavelength band on the long wavelength side. If the short wavelength side is set to a wavelength band of 1.3 μm and the long wavelength side is set to a wavelength of 1.55 μm, a commercially available WDM coupler can be used.
[0086]
The group branching filter 7b shown in FIG. 28 (b) is configured such that the operating wavelength of the signal light for connecting the HCN inside the sub HCN and the operating wavelength of the signal light for connecting the sub HCNs alternate. Applied to Such a group branching filter 7b can be realized, for example, by splitting an input wavelength multiplexed signal light into two using an optical coupler or the like, and connecting a Fabry-Perot filter having a periodic transmission wavelength to each output.
[0087]
As described above, in the present embodiment, the AWG1 for connection within the sub-HCN, the AWG5 for signal output and the AWG6 for signal input for connection between the sub-HCNs are prepared, and the connection between the inside and outside of the sub-HCN is separated from the outside of the AWG. By realizing with the group splitter 7 and the group multiplexer 8, the same function as that of the second embodiment can be realized with only two signal lines inputting and outputting to each node. Further, by combining optical circulators, it becomes possible to use only one input / output signal line for each node. In the configuration of the present embodiment, the degree of freedom in wavelength selection is large. For example, as described above, inexpensive 1.3 μm band optical components are used for connection within the sub-HCN, and 1.55 μm band optical components capable of long-distance transmission are used for connection between the sub-HCNs. It becomes possible. Therefore, a network can be realized at low cost.
[0088]
The HCN shown in FIG. 27 has a configuration in which two tertiary HCNs consisting of eight nodes are connected to realize a quaternary HCN (16 nodes). Since the AWG for network expansion has eight ports, if all of these ports are used, a maximum of 256 sub HCNs can be connected to the HCN. In that case, the 11th-order HCN (2048 nodes) as a whole, and the number of input / output wavelength signals of each node is 11.
[0089]
FIG. 29 shows an example in which the configuration (FIG. 1) of the first embodiment is applied as a sub HCN of the third embodiment. In the figure, nodes 0000 to 1111, AWG 1 and optical couplers 2 and 3 correspond to the configuration of the first embodiment shown in FIG. 1 and are similarly connected. In addition, the group splitter 7 and the group multiplexer 8, the signal output AWG 5 and the signal input AWG 6 used for connection between sub HCNs correspond to the third embodiment shown in FIG.
[0090]
Here, the group splitter 7-1 splits the output signal light from the nodes 0000 to 0111, and connects them to the input ports 0 to 7 of the AWG1 and the input ports 8 to 15 of the AWG5 for signal output. The group splitter 7-2 splits the output signal light from the nodes 1000 to 1111 and connects them to the input ports 0 to 7 of the AWG 1 and the input ports 0 to 7 of the AWG 5 for signal output. The group multiplexer 8-1 connects the output signal lights of the output ports 0 to 7 of the AWG 1 and the output ports 15 to 8 of the AWG 6 for signal input to the nodes 0000 to 0111. The group multiplexer 8-2 connects the output signal lights of the output ports 0 to 7 of the AWG 1 and the output ports 0 to 7 of the signal input AWG 6 to the nodes 1111 to 1000.
[0091]
With such a configuration, the HCN can be configured using the AWG having a small number of ports, and a network can be economically constructed. The number of nodes of the sub HCN in FIG. 29 is 16, which is a fourth-order HCN. Since the signal input / output AWGs 5 and 6 used for connection between the sub HCNs in this sub HCN are 16 ports, if all of them are used, 2 ¹⁶ HCN connections can be made to the number of sub HCNs. In that case, the total is 20th-order HCN (1,048,576 nodes).
[0092]
As described above, in the third embodiment shown in FIGS. 27 to 29, the number of input / output signal lines to each node can be reduced, and HCN can be realized economically.
[0093]
(Fourth embodiment)
FIG. 30 shows a fourth embodiment of the wavelength division multiplexing network of the present invention. In the present embodiment, in the second and third embodiments, a wavelength division multiplexing / time division conversion circuit (WDM / TDM) is connected to an output port of a signal output AWG 5 provided for connection with another sub-HCN. By connecting a time multiplexing / wavelength multiplexing conversion circuit (TDM / WDM) to the input port of the signal input AWG 6, a recursive network can be constructed.
[0094]
In the figure, the sub HCN 9 is one sub HCN of the third embodiment shown in FIG. 27 here. The WDM / TDM 10 is connected to the output ports 0 to 7 of the signal output AWG 5, respectively, and the output is wavelength-multiplexed by the wavelength multiplexing circuit 11 and output to the outside. The wavelength-division multiplexed signal from the outside is wavelength-separated by the wavelength separation circuit 12, and further connected to the input ports 0 to 7 of the signal input AWG 6 via the corresponding TDM / WDM 13. FIG. 30 shows a state where such a sub HCN 9 is hierarchically connected as one node.
[0095]
FIG. 31 shows a configuration example of the WDM / TDM 10 connected to each output port of the signal output AWG 5. The WDM / TDM 10 includes a WDM / TDM converter 14 and a light source 15.
[0096]
The WDM / TDM converter 14 receives wavelength multiplexed signal light (λ0 to λ3 in the figure). Here, each wavelength signal light is an intensity-modulated pulse signal. The WDM / TDM conversion unit 14 splits the input plurality of wavelength signal lights, converts them into electric signals for each wavelength, compresses the pulse width, and multiplexes them on the time axis. Further, the light of wavelength λa output from the light source 15 is modulated by the time division multiplexed signal and output. Note that the light source 15 may use a light source whose oscillation wavelength is determined in advance, or may use a wavelength variable light source. As described above, the WDM / TDM 10 has a function of converting optical signals of a plurality of different wavelengths into optical signals of a single wavelength. Here, an intensity-modulated optical signal is assumed as the input / output signal light, but other modulation methods such as phase modulation and frequency modulation may be used.
[0097]
The wavelengths of the respective light sources 15 of the WDM / TDM 10 connected to the respective output ports of the signal output AWG 5 are different from each other, and the signals multiplexed with the light of the different single wavelengths by the wavelength multiplexing circuit 11 shown in FIG. The wavelength is multiplexed. The wavelength-multiplexed signal is wavelength-separated by the wavelength separation circuit 12 in FIG. 30 and input to each TDM / WDM 13.
[0098]
FIG. 32 shows a configuration example of the TDM / WDM 13 connected to each input port of the AWG 6 for signal input. The TDM / WDM 13 includes a TDM / WDM conversion unit 16 and a plurality of light sources 17, and performs an operation opposite to that of the WDM / TDM 10.
[0099]
The TDM / WDM conversion unit 16 receives a signal that is time-multiplexed with light of a single wavelength and temporarily converts the signal into an electric signal to generate a plurality of time-multiplexed demultiplexed signals. Each of the time-division-multiplexed signals modulates light from the light source 17 having a different wavelength from each other, wavelength-multiplexes the signals, and outputs the resulting signals. As the plurality of light sources 17, a plurality of light sources having different wavelengths may be used, or a variable wavelength light source may be used.
[0100]
As described above, by adding the WDM / TDM 10 and the TDM / WDM 13 to the input / output terminal of the sub HCN, the sub HCN can be embedded in a node portion of a network having the same configuration as the sub HCN. At that time, the wavelength of the signal light output from the WDM / TDM 10 and the wavelength of the signal light output from the TDM / WDM 13 need to be set so that the entire network constitutes the HCN. In FIG. 30, a tertiary HCN composed of eight nodes is recursively configured twice to realize a sixth-order HCN composed of 64 nodes. By repeating the same configuration, it is possible to further expand the network scale.
[0101]
FIG. 33 shows a physical network configuration when a network is configured recursively using the fourth embodiment. In the figure, reference numeral 21 denotes a node in the sub HCN, reference numeral 22 denotes a circuit portion including an AWG other than the node of the sub HCN, and reference numeral 23 denotes a circuit portion other than the node of the upper network when the network is configured recursively.
[0102]
Since the sub-HCN can be regarded as having a star network configuration centered on AWG, the recursive network configuration has a hierarchical star network configuration as shown in the figure. This is close to the configuration of the current communication network, and can be said to have good compatibility with existing networks. In addition, since the capacity of the signal multiplexed on each optical fiber increases toward the upper level of the hierarchy, the configuration combined with the second embodiment of the present invention can be considered as a realistic realization method.
[0103]
As described above, according to the present embodiment, in a wavelength multiplexing network in which sub HCNs are connected to each other by HCN to form a large-scale HCN, a recursive network configuration is realized by combining WDM / TDM 10 and TDM / WDM 13. And a large-scale HCN can be realized.
[0104]
(Fifth embodiment)
By the way, in the second and third embodiments, the AWG is used to connect the sub HCNs, and the wiring between them becomes complicated depending on the number of ports of the AWG and the number of sub HCNs to be connected. For example, if the number of ports of the AWG is 4, HCN connection of a maximum of 16 sub HCNs is possible, but if the sub HCNs are separated from each other, it is not easy to make an HCN connection between them. In the fifth embodiment, cable laying between sub-HCNs is facilitated by using spatial multiplexing (SDM).
[0105]
FIG. 34 shows a fifth embodiment of the wavelength division multiplexing network of the present invention. In this embodiment, in order to connect the sub HCNs 00 to 11, the input / output lines connected to the signal output AWG 5 and the signal input AWG 6 of each sub HCN are accommodated in the multi-core optical fiber cable 24, and the interconnection node 25. The configuration inside the sub HCN may be any of the second and third embodiments.
[0106]
The interconnection node 25 connects a plurality of input / output lines by HCN. For the HCN connection in the interconnection node 25, an optical fiber may be HCN connected, or a waveguide pattern for HCN connection using a planar optical waveguide may be formed. The signal output AWG 5 and the signal input AWG 6 of each sub HCN have four ports, and up to 16 sub HCNs can be connected. Therefore, the interconnection node 25 has an empty port for it.
[0107]
In this way, the configuration in which the input / output lines of the sub-HCN are connected to the interconnection node 25 and the HCN connection is made in the connection node 25 makes it possible to make the HCN connection between the sub-HCNs located at remote positions directly. This simplifies the wiring and simplifies the work of laying the optical fiber. This makes it possible to construct the HCN economically.
[0108]
(Sixth embodiment)
FIG. 35 shows a sixth embodiment of the wavelength division multiplexing network of the present invention. This embodiment shows a configuration in which a large-scale HCN is realized hierarchically by combining the embodiments described above.
[0109]
In the figure, 26 is a node, 27 is a node composed of AWG and group multiplexer / demultiplexer, WDM / TDM and TDM / WDM, 28 is a node composed of AWG and group multiplexer / demultiplexer, 29 is an interconnection node, and 30 to 33 Represents the first to fourth sub HCN layers. The configuration of each layer is, for example, applying the configuration of the fourth embodiment (FIG. 30) to the first and second layers, and applying the configuration of the fifth embodiment (FIG. 34) to the third layer. The fourth hierarchy has a configuration in which nodes are directly HCN-connected. As described above, by forming the HCN hierarchically by combining the embodiments of the present invention and the configuration for directly connecting the HCN, it is possible to realize a large-scale HCN in a form consistent with the existing communication network. .
[0110]
Here, a specific numerical example of the transmission capacity that can be realized by hierarchization of sub HCNs will be described.
In the first layer, if the transmission capacity of each node is 2.5 [Gbit / s] × 4 channels (4 waves) and the number of nodes is 16, 10 [Gbit / s] × 16 = 160 [Gbit / s] Realize.
[0111]
Up to the second layer, the transmission capacity of each node is 2.5 [Gbit / s] × 8 channels (8 waves), the number of nodes is 256, and 20 [Gbit / s] × 256 = 5.12 [Tbit / s] ] Is realized.
Up to the third layer, the transmission capacity of each node is 2.5 [Gbit / s] × 12 channels (12 waves), the number of nodes is 4,096, and 30 [Gbit / s] × 4096 = 122.88 [Tbit] / S] is realized.
[0112]
Up to the fourth layer, the transmission capacity of each node is 2.5 [Gbit / s] × 16 channels (16 waves), the number of nodes is 65,536, and 40 [Gbit / s] × 65536 = 2.62 [Pbit] / S] is realized.
[0113]
As described above, according to the present embodiment, a large-scale HCN can be realized by configuring the HCN hierarchically by combining the configurations of the first to fifth embodiments of the present invention. Moreover, even when a petabit network can be realized by layering as described above, the processing speed of each node does not increase dramatically in the higher layers, and the current technology can sufficiently cope with it.
[0114]
【The invention's effect】
As described above, the wavelength multiplexing network of the present invention has the following effects in an HCN that combines a WDM system and a repetitive wavelength division multiplexing / demultiplexing element (for example, AWG).
[0115]
By connecting an optical coupler to an input / output port of the AWG and connecting a plurality of nodes to the input / output port of the AWG, a large-scale HCN can be realized using a small number of ports of the AWG.
[0116]
Further, by using the AWG for signal input / output between the sub HCNs, the HCN can be further expanded.
Also, by separating a wavelength band for HCN connection in the sub HCN and a wavelength band for HCN connection between the sub HCNs, and using a group multiplexer / demultiplexer for multiplexing / demultiplexing for each wavelength band, the connection inside / outside the sub HCN can be AWG. And the number of wirings can be reduced as a whole.
[0117]
Also, by using each of the WDM / TDM and TDM / WDM conversion circuits at the time of sub HCN connection, a recursive network configuration becomes possible, and a large-scale network with good consistency with the current network configuration is economically realized. can do.
[0118]
Furthermore, a large-scale and large-capacity network can be realized at low cost by combining the above-described configurations.
The wavelength division multiplexing network of the present invention is mainly assumed to be applied to LANs and WANs. However, the application field is not limited to this. The present invention can also be applied to an inter-network, or a wiring in a router or an ATM switch.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a wavelength division multiplexing network of the present invention.
FIG. 2 is a view for explaining a process of configuring a fourth-order HCN (16 nodes) using an 8-port AWG.
FIG. 3 is a diagram showing a connection relationship (1) of a quaternary HCN by an 8-port AWG.
FIG. 4 is a diagram showing a connection relationship (2) of a quaternary HCN by an 8-port AWG.
FIG. 5 is a diagram showing a connection relationship (3) of a quaternary HCN by an 8-port AWG.
FIG. 6 is a diagram showing a connection relationship (4) of a quaternary HCN by an 8-port AWG.
FIG. 7 is a diagram showing a connection relationship (others) of a quaternary HCN by an 8-port AWG.
FIG. 8 is a diagram showing a connection relationship (1) of a fifth-order HCN by a 16-port AWG.
FIG. 9 is a diagram showing a connection relationship (2) of a fifth-order HCN by a 16-port AWG.
FIG. 10 is a diagram showing a connection relationship (3) of a fifth-order HCN by a 16-port AWG.
FIG. 11 is a diagram showing a connection relationship (4) of a fifth-order HCN by a 16-port AWG.
FIG. 12 is a view showing a connection relationship (1) of a sixth-order HCN by a 32-port AWG.
FIG. 13 is a diagram showing a connection relationship (2) of a sixth-order HCN by a 32-port AWG.
FIG. 14 is a diagram showing an example of an HCN pattern.
FIG. 15 is a view showing a connection relationship (FIGS. 12 and 13) of a sixth-order HCN by a 32-port AWG.
FIG. 16 is a diagram showing a connection relationship (1) of a seventh-order HCN by a 32-port AWG.
FIG. 17 is a diagram showing a connection relationship (2) of a seventh-order HCN by a 32-port AWG.
FIG. 18 is a diagram showing a connection relationship (3) of a seventh-order HCN by a 32-port AWG.
FIG. 19 is a view for explaining Condition 2 of configuring a 7th-order HCN using a 32-port AWG.
FIG. 20 is a view for explaining condition 3 of configuring a seventh-order HCN using a 32-port AWG.
FIG. 21 is a view for explaining Condition 4 of configuring a 7th-order HCN using a 32-port AWG.
FIG. 22 is a view showing a connection relationship between a 32-port AWG and a node in the seventh-order HCN.
FIG. 23 is a view showing an HCN pattern of a seventh-order HCN by a 32-port AWG.
FIG. 24 is a diagram showing a second embodiment of the wavelength division multiplexing network of the present invention.
FIG. 25 is a diagram showing a relationship between input / output ports of signal input / output AWGs 5 and 6, and input / output wavelengths.
FIG. 26 is a diagram showing a connection relationship of a quaternary HCN.
FIG. 27 is a diagram showing a third embodiment of the wavelength division multiplexing network of the present invention.
FIG. 28 is a view for explaining functions of the group branching filter 7;
FIG. 29 is a diagram showing an example in which the configuration (FIG. 1) of the first embodiment is applied as a sub HCN of the third embodiment.
FIG. 30 is a diagram showing a fourth embodiment of the wavelength division multiplexing network of the present invention.
FIG. 31 is a diagram showing a configuration example of a WDM / TDM 10.
FIG. 32 is a diagram showing a configuration example of a TDM / WDM 13.
FIG. 33 is a diagram illustrating a physical network configuration when a network is configured recursively using the fourth embodiment;
FIG. 34 is a diagram showing a fifth embodiment of the wavelength division multiplexing network of the present invention.
FIG. 35 is a diagram showing a sixth embodiment of the wavelength division multiplexing network of the present invention.
FIG. 36 is a diagram showing a configuration example of a conventional wavelength multiplexing network using a star coupler.
FIG. 37 is a diagram showing a conventional example that realizes HCN by combining the WDM method and AWG.
FIG. 38 is a diagram showing a configuration of a hypercube network.
FIG. 39 is a diagram showing the relationship between signal wavelengths between input / output ports of the AWG and nodes connected to the input / output ports.
[Explanation of symbols]
1 Array waveguide diffraction grating type filter (AWG)
2,3 optical coupler
5 AWG for signal output
6 AWG for signal input
7 Group splitter
8 group multiplexer
9 Sub HCN
10. Wavelength multiplexing / time multiplexing conversion circuit (WDM / TDM)
11 Wavelength multiplexing circuit
12. Wavelength separation circuit
13. Time multiplexing / wavelength multiplexing conversion circuit (TDM / WDM)
14 WDM / TDM converter
15 Light source
16 TDM / WDM converter
17 Light source
21 Node in Sub HCN
22 Circuit part including AWG other than sub HCN node
23 Circuit parts other than nodes of the upper network
24 multi-core optical fiber cable
25 Interconnection Node
26 nodes
27 Node consisting of AWG, group multiplexer / demultiplexer, WDM / TDM and TDM / WDM
28 Node consisting of AWG and group multiplexer / demultiplexer
29 Interconnection Node
30 to 33 1st to 4th sub HCN levels

Claims (10)

An optical transmission unit that multiplexes a plurality of wavelength signal lights and transmits the multiplexed signal light as wavelength multiplexed signal light, and a plurality of nodes including an optical reception unit that receives the wavelength multiplexed signal light by demultiplexing the wavelength multiplexed signal light into the plurality of wavelength signal lights,
It has a plurality of input ports and a plurality of output ports, demultiplexes the wavelength multiplexed signal light input from each input port to different output ports, and separates the signal light of different wavelengths input from the plurality of input ports into each A wavelength division multiplexing / demultiplexing element for multiplexing and outputting to the output port,
In a wavelength multiplexing network for connecting hypercube network connection (hereinafter referred to as "HCN connection") between nodes differing only by one bit of a node number in binary representation from among the plurality of nodes via the wavelength division multiplexing / demultiplexing device,
Multiplexing means for multiplexing wavelength multiplexed signal lights output from the plurality of nodes in a predetermined combination, respectively, and connecting to a predetermined input port of the wavelength multiplexing / demultiplexing element;
Branching means for branching the wavelength division multiplexed signal light output from the output port of the wavelength division multiplexing / demultiplexing element into a plurality of parts and connecting to a plurality of predetermined nodes;
The node numbers of the plurality of nodes, the wavelength and the number of input / output signal lights, and the input / output ports of the wavelength division multiplexing / demultiplexing element connected to each node are set so as to establish HCN connection. Wavelength multiplexing network. The wavelength division multiplexing network according to claim 1,
A plurality of nodes connected to the input port of the wavelength division multiplexing element via the multiplexing means, and a plurality of nodes connected to the output port of the wavelength division multiplexing element via the branching means, 1. A wavelength division multiplexing network, wherein the number of combinations of HCN connections between nodes between the nodes is one or less, and the node numbers of other nodes are different from each other by at least two bits. In the wavelength multiplexing network according to claim 1 or 2,
When the number of input / output ports of the wavelength division multiplexing / demultiplexing device is 2 ⁿ (n is an integer of 3 or more), two nodes are connected to each input / output port, and 2 ^{n + 1} nodes are HCN-connected. A wavelength-division multiplexing network comprising an (n + 1) -order or a (n + 2) -order hypercube network in which four nodes are connected to respective input / output ports and 2 ^{n + 2} nodes are HCN-connected. In a wavelength multiplexing network in which a plurality of nodes are HCN-connected to a plurality of sub-hypercube networks connected to each other by HCN,
The node includes: an optical transmission unit that multiplexes wavelength signal light addressed to each node connected to HCN of another sub-hypercube network and transmits the multiplexed signal light as wavelength multiplexed signal light; An optical receiving unit that receives the wavelength signal light transmitted from as a wavelength multiplexed signal light, receives the wavelength signal light by demultiplexing,
The sub-hypercube network has a plurality of input ports and a plurality of output ports, splits the wavelength multiplexed signal light input from each input port into different output ports, and outputs the wavelength-multiplexed signal light from the plurality of input ports. Two wavelength multiplexing / demultiplexing elements for multiplexing and outputting signal lights of different wavelengths to respective output ports are provided for output and input to another sub-hypercube network,
A wavelength multiplexed signal light transmitted from each node in the sub-hypercube network to another sub-hypercube network is connected to each input port of the output wavelength multiplexing / demultiplexing element, and each of the input wavelength multiplexing / demultiplexing elements is connected. Connect the wavelength multiplexed signal light output from the output port to each node,
Connecting each output port of the output wavelength demultiplexing element and each input port of the input wavelength demultiplexing element of the sub hypercube network between the sub-hypercube networks to be HCN-connected,
The node numbers of the plurality of nodes, the wavelength and the number of input / output signal lights, and the input / output ports of the wavelength division multiplexing / demultiplexing element connected to each node are set so as to establish HCN connection. Wavelength multiplexing network. The wavelength division multiplexing network according to claim 4,
The wavelength multiplexing network according to claim 1, wherein the sub-hypercube network is the wavelength multiplexing network according to claim 1. In the wavelength multiplexing network according to claim 4 or 5,
The node includes a wavelength multiplexed signal light for a sub-hypercube network to which the node belongs (hereinafter, referred to as “own sub-HCN”) and a wavelength multiplexed signal for another sub-hypercube network (hereinafter, referred to as “other sub-HCN”). An optical transmitting unit that multiplexes and transmits light, and an optical receiving unit that receives the wavelength division multiplexed signal light for the own sub-HCN and the wavelength division multiplexed signal light for the other sub-HCN,
The sub-hypercube network includes a wavelength division multiplexing / demultiplexing element for demultiplexing the wavelength multiplexed signal light for the own sub HCN and the other sub HCN transmitted from the node, and performing HCN connection with the own sub HCN, and the output. Group demultiplexer connected to the wavelength multiplexing / demultiplexing element for use, a wavelength multiplexing / demultiplexing element for performing HCN connection with the own sub HCN, and the self-sub HCN and the other sub HCN input from the input wavelength multiplexing / demultiplexing element And a group multiplexer for multiplexing wavelength multiplexed signal light for use and connecting to each of the nodes. The wavelength multiplexing network according to any one of claims 4 to 6,
The sub-hypercube network is
A wavelength-division multiplexing / time-division conversion circuit that converts wavelength-division multiplexed signal light into time-multiplexed single-wavelength signal light and outputs it, and converts a time-multiplexed single-wavelength signal light into wavelength-multiplexed signal light and outputs it Time multiplexing / wavelength multiplexing conversion circuit
The wavelength multiplexing / time multiplexing conversion circuit is connected to each output port of an output wavelength multiplexing / demultiplexing device for connection to the other sub-hypercube network, and output from each output port of the output wavelength multiplexing / demultiplexing device. A wavelength multiplexing circuit that converts the wavelength-multiplexed signal light into time-multiplexed signal light of different single wavelengths, wavelength-multiplexes the signal light, and outputs it.
A wavelength demultiplexing circuit for demultiplexing wavelength-multiplexed signal light input from the outside and inputting the time-multiplexed signal light having a different single wavelength to the time-multiplexing / wavelength-multiplexing conversion circuit; The wavelength-division multiplexed signal light converted from the time-multiplexed signal light in the multiplex conversion circuit is connected to each input port of the wavelength-division multiplexing / demultiplexing element for input for connection to the other sub-hypercube network,
A wavelength-division multiplexing network comprising a sub-hypercube network provided with each of the circuits as a node of the wavelength-division multiplexing network according to claim 4. A wavelength multiplexing network comprising a sub-hypercube network according to claim 7 as a node of the wavelength multiplexing network according to claim 1 to form a hypercube network. The wavelength multiplexing network according to any one of claims 4 to 6,
When connecting each output port of the wavelength multiplexing / demultiplexing element for output and each input port of the wavelength multiplexing / demultiplexing element for input between the sub-hypercube networks to be HCN-connected, A multi-core optical fiber cable for concentrating a plurality of optical fibers connected to each output port and each input port of the wavelength division multiplexing / demultiplexing device, and the other end of the multi-core optical fiber cable connected to each of the sub-hypercube networks is provided. A wavelength division multiplexing network having a configuration in which the core wires are collected at one location and HCN connections are made. A wavelength division multiplexing network, wherein the wavelength division multiplexing networks according to any one of claims 1 to 9 are combined with each other to form a hypercube network having a hierarchical structure.

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