Optical transmitting device, optical receiving device, optical communication device, optical communication system, and control method thereof

Abstract

To provide an optical transmitting device capable of performing efficient resource allocation in an optical communication network.SOLUTION: An optical transmitting device (1_1) comprises: a first transmission unit (11_1) that transmits a first optical transmission signal (21_1); a second transmission unit (11_2) that transmits a second optical transmission signal (21_2); and an output unit that outputs both the first optical transmission signal (21_1) and the second optical transmission signal (21_2) to a first path (26_1) in a case where the first optical transmission signal (21_1) and the second optical transmission signal (21_2) share a series of information, and that outputs any one of the first optical transmission signal (21_1) and the second optical transmission signal (21_2) to a second path (26_2) in a case where the first optical transmission signal (21_1) and the second optical transmission signal (21_2) do not share the series of information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical transmitting device, an optical receiving device, an optical communication device, an optical communication system, and a control method thereof. [Background technology]

[0002] With the explosive increase in demand for broadband multimedia communication services such as the Internet and video distribution, the introduction of long-distance, high-capacity, and highly reliable dense wavelength multiplexing optical fiber communication systems is progressing in trunk and metro systems. In addition, the spread of optical fiber access services is also rapidly progressing in subscriber systems. In such communication systems using optical fibers, it is important to reduce the laying cost of optical fibers, which are optical transmission paths, and to increase the efficiency of the transmission bandwidth per optical fiber. For this reason, wavelength division multiplexing (WDM), which multiplexes and transmits optical signals of multiple different wavelengths, is widely used. In WDM technology, one wavelength is used for one channel. Meanwhile, recently, superchannel technology, which can realize a transmission capacity of more than 100 Gbps per WDM channel bandwidth, has attracted attention. In this superchannel technology, multiple wavelengths (subcarriers) are used for the bandwidth of one channel, so wavelengths can be multiplexed densely. Therefore, this superchannel technology will become important in the future to further increase the transmission capacity to 400 Gbps and 1 Tbps.

[0003] Patent Document 1 and Patent Document 2 disclose technologies relating to optical communications using WDM. Patent Document 1 discloses technology relating to optical network equipment capable of efficient network operation, management, and maintenance. Patent Document 2 discloses technology relating to optical transmission equipment capable of reducing the influence of mutual mixing noise when transmitting an electrical signal including multiple subcarriers by analog optical modulation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-008513 A [Patent Document 2] JP 2008-206063 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a communication network, traffic between certain nodes varies. Therefore, transmission between certain nodes does not always need to be performed at the maximum transmission capacity. On the other hand, as explained in the background art, in optical communication using WDM technology, one wavelength is used for one channel. Therefore, in optical communication devices using WDM technology, the only options are to either turn off communication or to communicate at the maximum transmission capacity, and it is not possible to set the transmission capacity to an intermediate value.

[0006] In contrast, when super-channel technology is used, multiple wavelengths are used in the band of one WDM channel, so the transmission capacity can be set to an intermediate value. Based on this, the inventors discovered that if the transmission capacity is set to an intermediate value by using some of the multiple wavelengths in the band of one channel for a transmission device, the remaining wavelengths can be used to allocate resources to other transmission devices.

[0007] In view of the above, an object of the present invention is to provide an optical transmitting device, an optical receiving device, an optical communication device, an optical communication system, and a control method thereof, which are capable of performing efficient resource allocation in an optical communication network. [Means for solving the problem]

[0008] An optical transmission device according to the present invention comprises a first transmitting unit that transmits a first optical transmission signal, a second transmitting unit that transmits a second optical transmission signal, and an output unit that outputs both the first optical transmission signal and the second optical transmission signal to a first path when the first optical transmission signal and the second optical transmission signal share a set of information, and outputs either the first optical transmission signal or the second optical transmission signal to a second path when the first optical transmission signal and the second optical transmission signal do not share the set of information.

[0009] An optical receiving device according to the present invention comprises first and second receiving units that receive a subcarrier reception signal, and a switching unit that outputs the input first subcarrier reception signal and second subcarrier reception signal to the first and second receiving units, wherein when the first and second subcarrier reception signals share a series of information, the switching unit receives the first and second subcarrier reception signals via the same path and outputs the first subcarrier reception signal to the first receiving unit and the second subcarrier reception signal to the second receiving unit, respectively, and when the first subcarrier reception signal and the second subcarrier reception signal do not share the series of information, the switching unit receives the first and second subcarrier reception signals via different paths, respectively, and outputs the first subcarrier reception signal to the first receiving unit and the second subcarrier reception signal to the second receiving unit.

[0010] The optical communication device according to the present invention includes a first transmitting unit that transmits a first optical transmission signal, a second transmitting unit that transmits a second optical transmission signal, an output unit that outputs both the first optical transmission signal and the second optical transmission signal to a first path when the first optical transmission signal and the second optical transmission signal share a series of information, and outputs either the first optical transmission signal or the second optical transmission signal to a second path when the first optical transmission signal and the second optical transmission signal do not share the series of information, first and second receiving units that receive a subcarrier reception signal, and an input and a switching unit which outputs a first subcarrier reception signal and a second subcarrier reception signal to the first and second receiving units, wherein when the first subcarrier reception signal and the second subcarrier reception signal share a series of information, the switching unit outputs the first subcarrier reception signal to the first receiving unit and the second subcarrier reception signal to the second receiving unit, and when the first subcarrier reception signal and the second subcarrier reception signal do not share the series of information, the switching unit outputs the first subcarrier reception signal to the second receiving unit.

[0011] An optical communication system according to the present invention is an optical communication system comprising an optical transmitting device and first and second optical receiving devices, wherein the optical transmitting device comprises a first transmitting unit that transmits a first optical transmission signal, a second transmitting unit that transmits a second optical transmission signal, and an output unit that outputs both the first optical transmission signal and the second optical transmission signal to the first optical receiving device when the first optical transmission signal and the second optical transmission signal share a set of information, and outputs either the first optical transmission signal or the second optical transmission signal to the second optical receiving device when the first optical transmission signal and the second optical transmission signal do not share the set of information.

[0012] The optical communication system of the present invention comprises an optical transmitting device that transmits first and second optical transmission signals, first and second optical receiving devices that receive the first and second optical transmission signals, and a controller that controls the optical transmitting device, and in response to instructions from the controller, the optical transmitting device outputs the first optical transmission signal and a second optical transmission signal that shares a set of information with the first optical transmission signal to the first optical receiving device, and outputs a second optical transmission signal that does not share a set of information with the first optical transmission signal to the second optical receiving device.

[0013] An optical communication system according to the present invention is an optical communication system comprising first and second optical transmitting devices and an optical receiving device, wherein the optical receiving device comprises first and second receiving units that receive a subcarrier reception signal, and a switching unit that outputs the input first subcarrier reception signal and second subcarrier reception signal to the first and second receiving units, and when the first and second subcarrier reception signals share a series of information, the switching unit receives the first and second subcarrier reception signals from the same optical transmitting device and outputs the first subcarrier reception signal to the first receiving unit and the second subcarrier reception signal to the second receiving unit, respectively, and when the first subcarrier reception signal and the second subcarrier reception signal do not share the series of information, the switching unit receives the first and second subcarrier reception signals from different optical transmitting devices, and outputs the first subcarrier reception signal to the first receiving unit and outputs the second subcarrier reception signal to the second receiving unit.

[0014] A controller according to the present invention, in an optical communication system including an optical transmitting device and first and second optical receiving devices, causes the optical transmitting device to output a first optical transmission signal and a second optical transmission signal that shares a series of information with the first optical transmission signal to the first optical receiving device, and to output a second optical transmission signal that does not share a series of information with the first optical transmission signal to the second optical receiving device.

[0015] A control method for an optical communication system according to the present invention is a control method for an optical communication system comprising an optical transmitting device and first and second optical receiving devices, wherein the optical transmitting device comprises a first transmitting unit that transmits a first optical transmission signal, a second transmitting unit that transmits a second optical transmission signal, and an output unit that outputs both the first optical transmission signal and the second optical transmission signal to the first optical receiving device when the first optical transmission signal and the second optical transmission signal share a set of information, and outputs either the first optical transmission signal or the second optical transmission signal to the second optical receiving device when the first optical transmission signal and the second optical transmission signal do not share the set of information, and controls the optical transmitting device and the first and second optical receiving devices respectively according to the communication state of the optical communication system.

[0016] A program according to the present invention is a program for controlling an optical communication system comprising an optical transmitting device and first and second optical receiving devices, wherein the optical transmitting device comprises a first transmitting unit for transmitting a first optical transmission signal, a second transmitting unit for transmitting a second optical transmission signal, and an output unit for outputting both the first optical transmission signal and the second optical transmission signal to the first optical receiving device when the first optical transmission signal and the second optical transmission signal share a set of information, and for outputting either the first optical transmission signal or the second optical transmission signal to the second optical receiving device when the first optical transmission signal and the second optical transmission signal do not share the set of information, and the program is for causing a computer to execute a process of controlling the optical transmitting device and the first and second optical receiving devices according to the communication state of the optical communication system.

[0017] An optical transmission method according to the present invention generates a first optical transmission signal, generates a second optical transmission signal, and if the first optical transmission signal and the second optical transmission signal share a set of information, outputs both the first optical transmission signal and the second optical transmission signal to a first path, and if the first optical transmission signal and the second optical transmission signal do not share the set of information, outputs either the first optical transmission signal or the second optical transmission signal to a second path.

[0018] In an optical receiving method according to the present invention, when first and second subcarrier reception signals share a series of information, the first and second subcarrier reception signals are received via the same route, and the first subcarrier reception signal is output to a first receiving unit and the second subcarrier reception signal is output to a second receiving unit, respectively; when the first subcarrier reception signal and the second subcarrier reception signal do not share the series of information, the first and second subcarrier reception signals are received via different routes, and the first subcarrier reception signal is output to the first receiving unit and the second subcarrier reception signal is output to the second receiving unit. Effect of the Invention

[0019] According to the present invention, it is possible to provide an optical transmitting device, an optical receiving device, an optical communication device, an optical communication system, and a control method thereof, which are capable of performing efficient resource allocation in an optical communication network. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing an optical transmitting device according to a first embodiment; [Diagram 2] FIG. 1 is a diagram illustrating an optical communication system according to a comparative example. [Diagram 3] FIG. 1 is a diagram illustrating an optical communication system according to a comparative example. [Figure 4] FIG. 1 is a diagram for explaining the effect of the present invention. [Diagram 5] FIG. 11 is a block diagram showing an optical transmitting device according to a second embodiment. [Figure 6] FIG. 2 is a diagram for explaining the arrangement of subcarriers. [Figure 7] FIG. 2 is a diagram for explaining the arrangement of subcarriers. [Figure 8] FIG. 11 is a block diagram showing an optical transmitting device according to a third embodiment. [Figure 9] FIG. 1 is a diagram illustrating an example of a subcarrier (WDM). [Figure 10]FIG. 13 is a diagram illustrating another example of subcarriers (OFDM modulation). [Figure 11] FIG. 11 is a block diagram showing an optical transmitting device according to a fourth embodiment. [Figure 12] FIG. 11 is a block diagram showing an optical transmitting device according to a fourth embodiment. [Figure 13] FIG. 11 is a block diagram showing an optical transmitting device according to a fourth embodiment. [Figure 14] FIG. 13 is a block diagram showing an optical receiving device according to a fifth embodiment. [Figure 15] FIG. 13 is a block diagram showing an optical receiving device according to a sixth embodiment. [Figure 16] FIG. 13 is a block diagram showing an optical receiving device according to a seventh embodiment. [Figure 17] FIG. 13 is a block diagram showing an optical receiving device according to an eighth embodiment. [Figure 18] FIG. 13 is a block diagram showing an optical receiving device according to an eighth embodiment. [Figure 19] FIG. 13 is a block diagram showing an optical receiving device according to an eighth embodiment. [Figure 20] FIG. 13 is a block diagram showing an optical communication device according to a ninth embodiment. [Figure 21] FIG. 23 is a block diagram showing an optical communication system according to a tenth embodiment. [Figure 22] FIG. 23 is a block diagram showing an optical communication system according to an eleventh embodiment. [Figure 23] FIG. 23 is a block diagram showing a controller provided in the optical communication system according to the eleventh embodiment. [Figure 24] FIG. 23 is a block diagram showing a controller provided in the optical communication system according to the twelfth embodiment. [Diagram 25] FIG. 23 is a block diagram showing an optical communication system according to a thirteenth embodiment. [Figure 26] FIG. 23 is a block diagram showing an optical communication system according to a fourteenth embodiment. [Figure 27] FIG. 23 is a block diagram showing an optical communication system according to a fifteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] <Embodiment 1> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an optical transmission device 1_1 according to the first embodiment. As shown in FIG. 1, the optical transmission device 1_1 according to the present embodiment includes a first transmission unit 11_1, a second transmission unit 11_2, and an output unit 12. In the following, the first and second transmission units may be referred to as subcarrier transmission units.

[0022] The first transmitting unit 11_1 transmits a first optical transmission signal 21_1. The second transmitting unit 11_2 transmits a second optical transmission signal 21_2. That is, transmission data is supplied to each of the first transmitting unit 11_1 and the second transmitting unit 11_2, and the first transmitting unit 11_1 and the second transmitting unit 11_2 generate a first optical transmission signal 21_1 and a second optical transmission signal 21_2 for transmitting the transmission data, respectively. The first optical transmission signal 21_1 and the second optical transmission signal 21_2 are signals for transmitting the transmission data using a subcarrier.

[0023] The optical transmitting device 1_1 according to the present embodiment uses a WDM technique for multiplexing and transmitting optical signals of multiple different wavelengths. That is, the first optical transmission signal 21_1 and the second optical transmission signal 21_2 generated by the first transmitting unit 11_1 and the second transmitting unit 11_2 have different wavelengths. In particular, the optical transmitting device according to the present embodiment can use a super-channel technique for allocating multiple wavelengths (subcarriers) to one channel band of WDM. By using this super-channel technique, it is possible to multiplex wavelengths at a high density, and to increase the transmission capacity.

[0024] When the first optical transmission signal 21_1 and the second optical transmission signal 21_2 share a series of information, the output unit 12 outputs both the first optical transmission signal 21_1 and the second optical transmission signal 21_2 to the same path (for example, the first path 26_1).

[0025] On the other hand, when the first optical transmission signal 21_1 and the second optical transmission signal 21_2 do not share a series of information, the output unit 12 outputs either the first optical transmission signal 21_1 or the second optical transmission signal 21_2 to the second path. For example, when the first optical transmission signal 21_1 and the second optical transmission signal 21_2 do not share a series of information, the output unit 12 may output the first optical transmission signal 21_1 to the first path 26_1 and output the second optical transmission signal 21_2 to the second path 26_2. Also, for example, when the first optical transmission signal 21_1 and the second optical transmission signal 21_2 do not share a series of information, the output unit 12 may output the first optical transmission signal 21_1 to the second path 26_2 and output the second optical transmission signal 21_2 to the first path 26_1. In other words, when the first optical transmission signal 21_1 and the second optical transmission signal 21_2 do not share a series of information, the output unit 12 outputs each of the first optical transmission signal 21_1 and the second optical transmission signal 21_2 to different paths.

[0026] Here, a case in which the first optical transmission signal 21_1 and the second optical transmission signal 21_2 share a series of information is, for example, a case in which the first transmitting unit 11_1 and the second transmitting unit 11_2 transmit predetermined transmission data in parallel using the first optical transmission signal 21_1 and the second optical transmission signal 21_2.

[0027] On the other hand, a case where the first optical transmission signal 21_1 and the second optical transmission signal 21_2 do not share a series of information is, for example, a case where the first transmitting unit 11_1 and the second transmitting unit 11_2 transmit predetermined transmission data independently using the first optical transmission signal 21_1 and the second optical transmission signal 21_2. That is, the first transmitting unit 11_1 transmits predetermined first transmission data using the first optical transmission signal 21_1, and the second transmitting unit 11_1 transmits predetermined second transmission data using the second optical transmission signal 21_1. In this case, since the first optical transmission signal 21_1 and the second optical transmission signal 21_2 each include independent transmission data, the first optical transmission signal 21_1 and the second optical transmission signal 21_2 can be output to separate paths (the first path 26_1 and the second path 26_2).

[0028] Here, the first path 26_1 is a path connected to a first optical receiving device (not shown), and the second path 26_2 is a path connected to a second optical receiving device (not shown).

[0029] In this way, in the optical transmitting device 1_1 according to the present embodiment, the output destinations of the first optical transmission signal 21_1 and the second optical transmission signal 21_2 are switched using the output unit 12. Therefore, it is possible to provide an optical transmitting device capable of performing efficient resource allocation. The reason for this will be described in detail below.

[0030] 2 and 3 are diagrams showing an optical communication system according to a comparative example, showing an example of an optical communication system using a super-channel technique. The optical communication system shown in FIG. 2 and FIG. 3 includes optical communication devices 101_a to 101_c. The optical communication device 101_a includes a plurality of transceivers 102_a and a single transceiver port 103_a. The plurality of transceivers 102_a are configured to be capable of transmitting and receiving using different wavelengths (subcarriers). In other words, the optical communication device 101_a can allocate a plurality of wavelengths (subcarriers) to a band of one channel of WDM. Each of the transceivers 102_a is configured to be capable of transmitting and receiving using each subcarrier. The same applies to the optical communication device 101_b and the optical communication device 101_c.

[0031] In the optical communication system shown in Figures 2 and 3, optical communication device 101_a and optical communication device 101_b are configured to be connectable via optical fiber 105, optical communication device 101_a and optical communication device 101_c are configured to be connectable via optical fiber 106, and optical communication device 101_b and optical communication device 101_c are configured to be connectable via optical fiber 107.

[0032] In the example shown in Figure 2, optical communication device 101_a and optical communication device 101_b are connected via optical fiber 105, and the optical communication device 101_a and the optical communication device 101_b are communicating at the maximum transmission capacity (100%).

[0033] In a communication network, traffic between certain nodes fluctuates. Therefore, transmission between the optical communication device 101_a and the optical communication device 101_b does not always need to be performed at the maximum transmission capacity. As explained in the background art, in optical communication using WDM technology, one wavelength is used for one channel. Therefore, in an optical communication device using WDM technology, the only options are to either turn off communication or to communicate at the maximum transmission capacity, and the transmission capacity cannot be set to an intermediate value.

[0034] On the other hand, when the super-channel technology is used, since multiple wavelengths are used in the band of one channel of WDM, the transmission capacity can be set to an intermediate value. Therefore, for example, as shown in FIG. 3, the transmission capacity between the optical communication device 101_a and the optical communication device 101_b can be set to 50% of the maximum transmission capacity. However, in this case, the transmission / reception unit 102_a of the optical communication device 101_a has an unused transmission / reception unit 108_a. Also, the transmission / reception unit 102_b of the optical communication device 101_b has an unused transmission / reception unit 108_b.

[0035] When the super-channel technique is used, signals transmitted and received by each of the transceivers 102_a share a set of information. In other words, each of the transceivers 102_a transmits and receives data in parallel. For this reason, the optical communication device 101_a is configured to transmit and receive optical signals via a single port 103_a. Therefore, even if an unused transceiver 108_a occurs among the transceivers 102_a of the optical communication device 101_a, the unused transceiver 108_a cannot be used for communication with another optical communication device 101_c, resulting in a problem of wasted resources.

[0036] Fig. 4 is a diagram for explaining the effect of the present invention. Note that, in Fig. 4, the effect of the present invention is explained using an optical communication device (an optical communication device capable of transmitting and receiving), but the effect of the present invention can be obtained in the same way in an optical transmitting device or an optical receiving device.

[0037] The optical communication system shown in Fig. 4 includes optical communication devices 110_a to 110_c. The optical communication device 110_a includes a plurality of transmitting / receiving units 111_a, a switching unit 112_a, and a plurality of transmitting / receiving ports 113_1a and 113_2a. The plurality of transmitting / receiving units 111_a are configured to be capable of transmitting / receiving signals using different subcarriers. In other words, the optical communication device 110_a can allocate a plurality of wavelengths (subcarriers) in a band of one channel of WDM. The same applies to the optical communication devices 110_b and 110_c.

[0038] In this way, the optical communication device 110_a includes a plurality of transmission / reception ports 113_1a, 113_2a, and can switch between the transmission / reception units 111_a connected to the plurality of transmission / reception ports 113_1a, 113_2a using the switching unit 112_a. Therefore, even if an unused transmission / reception unit occurs among the plurality of transmission / reception units 111_a of the optical communication device 110_a, the unused transmission / reception unit can be allocated to communication with other optical communication devices.

[0039] For example, in the optical communication system shown in Fig. 3, when the transmission capacity between the optical communication device 101_a and the optical communication device 101_b is set to 50% of the maximum transmission capacity, an unused transceiver 108_a is generated among the transceivers 102_a of the optical communication device 101_a, and resources are wasted. In contrast, in the optical communication system shown in Fig. 4, the unused transceiver (corresponding to the transceiver 108_a in Fig. 3) of the optical communication device 111_a is connected to the transceiver port 113_2a using the switching unit 112_a, so that the unused transceiver can be allocated to communication with the optical communication device 110_c. Therefore, efficient resource allocation can be performed in the optical communication network.

[0040] At this time, the optical communication device 110_a and the optical communication device 110_b communicate via a transmission / reception port 113_1a of the optical communication device 110_a and a transmission / reception port 113_1b of the optical communication device 110_b. The optical communication device 110_a and the optical communication device 110_c communicate via a transmission / reception port 113_2a of the optical communication device 110_a and a transmission / reception port 113_1c of the optical communication device 110_c. The optical communication device 110_b and the optical communication device 110_c communicate via a transmission / reception port 113_2b of the optical communication device 110_b and a transmission / reception port 113_2c of the optical communication device 110_c.

[0041] In addition, in FIG. 4, an example is shown in which the transmission capacity between each of the optical communication devices 110_a to 110_c is set to 50% of the maximum transmission capacity, but the transmission capacity between each of the optical communication devices 110_a to 110_c can be flexibly set by changing the number of each of the transmission / reception units connected to each of the transmission / reception ports using each of the switching units 112_a to 112_c.

[0042] According to the invention of the present embodiment described above, it is possible to provide an optical transmitting apparatus and an optical transmitting method capable of performing efficient resource allocation in an optical communication network.

[0043] <Embodiment 2> Next, a second embodiment of the present invention will be described. In the second embodiment, a detailed configuration of the optical transmitting device 1_1 described in the first embodiment will be described. Fig. 5 is a block diagram showing an optical transmitting device 1_2 according to the second embodiment. As shown in Fig. 5, the optical transmitting device 1_2 according to the present embodiment includes a plurality of subcarrier transmitting units 11_1 to 11_m, an output unit 12, and transmitting ports 13_1 and 13_2.

[0044] Transmission data is supplied to each of the plurality of subcarrier transmitters 11_1 to 11_m. The plurality of subcarrier transmitters (SCS_1 to SCS_m) 11_1 to 11_m generate optical transmission signals 21_1 to 21_m for transmitting the transmission data, respectively. Here, m is an integer equal to or greater than 2 and corresponds to the number of the subcarrier transmitters. The optical transmission signals 21_1 to 21_m are signals for transmitting the transmission data using subcarriers. For example, the subcarrier transmitter 11_1 generates the optical transmission signal 21_1 using the subcarrier SC1 corresponding to the subcarrier transmitter 11_1. Also, the subcarrier transmitter 11_2 generates the optical transmission signal 21_2 using the subcarrier SC2 corresponding to the subcarrier transmitter 11_2. In this manner, each of the subcarrier transmitters 11_1 to 11_m generates each of the optical transmission signals 21_1 to 21_m using each of the subcarriers SC1 to SCm corresponding to each of the subcarrier transmitters 11_1 to 11_m.

[0045] Here, each of the optical transmission signals 21_1 to 21_m (in other words, each of the subcarriers SC1 to SCm used when generating the optical transmission signals 21_1 to 21_m) can be set using a predetermined parameter. At this time, the parameters of each of the optical transmission signals 21_1 to 21_m are assigned so as not to overlap with each other. When a plurality of parameters are used as the predetermined parameters, each of the optical transmission signals 21_1 to 21_m is arranged on a matrix with the plurality of parameters as axes so as not to overlap with each other. For example, the predetermined parameter is at least one of wavelength, polarization, and time.

[0046] 6 and 7 are diagrams for explaining the arrangement of subcarriers. FIG. 6 shows an example of the arrangement of subcarriers when wavelength and time are used as predetermined parameters. In the case shown in FIG. 6, when each of the subcarriers SC1 to SC4 is arranged on a matrix (in this case, on an XY plane) with wavelength as the X axis and time as the Y axis, the subcarriers SC1 to SC4 are arranged so as not to overlap with each other on the matrix plane. In the example shown in FIG. 6, the wavelengths of each of the subcarriers SC1 to SC4 are set to λ1 to λ4, respectively, and further each of the subcarriers SC1 to SC4 is time-divided by time t1 to t4. That is, the subcarrier SC1 can be set using parameters (λ1, t1), the subcarrier SC2 can be set using parameters (λ2, t2), the subcarrier SC3 can be set using parameters (λ3, t3), and the subcarrier SC4 can be set using parameters (λ4, t4).

[0047] Also, Fig. 7 shows an example of subcarrier arrangement when wavelength and polarization are used as the predetermined parameters. In the case shown in Fig. 7, when each of the subcarriers SC1 to SC4 is arranged on a matrix (in this case, on an XY plane) with the wavelength as the X axis and the polarization as the Y axis, the subcarriers SC1 to SC4 are arranged so as not to overlap with each other on the matrix plane. In the example shown in Fig. 7, the wavelengths of each of the subcarriers SC1 to SC4 are set to λ1 to λ4, respectively, and further the polarizations of each of the subcarriers SC1 to SC4 are set to X polarization and Y polarization. That is, the subcarrier SC1 can be set using parameters (λ1, X polarization), the subcarrier SC2 can be set using parameters (λ2, Y polarization), the subcarrier SC3 can be set using parameters (λ3, X polarization), and the subcarrier SC4 can be set using parameters (λ4, Y polarization).

[0048] In this way, by allocating the parameters of each of the optical transmission signals 21_1 to 21_m so as not to overlap with each other, it is possible to reduce the influence of mutual interference between the subcarriers. Although the case where each subcarrier is set using two parameters has been described in Fig. 6 and Fig. 7, in this embodiment, each subcarrier may be set using three or more parameters.

[0049] Furthermore, when the above parameters include wavelength, the subcarrier transmitters 11_1 to 11_m may each include a light source (a light source that outputs light of a single wavelength; not shown) for generating the subcarriers SC1 to SCm. For example, the light source may be configured using a laser diode.

[0050] Further, the subcarrier transmitters 11_1 to 11_m may modulate the optical transmission signals 21_1 to 21_m using a predetermined modulation method. The modulation method may include amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), quadrature amplitude modulation (QAM), quadrature phase shift keying (QPSK), etc. As the quadrature amplitude modulation (QAM), for example, 16QAM, 64QAM, 128QAM, 256QAM, etc. may be used.

[0051] The output unit 12 selectively outputs the optical transmission signals 21_1-21_m output from the plurality of subcarrier transmitters 11_1-11_m to a plurality of transmission ports (PS_1, PS_2) 13_1, 13_2. Here, the transmission ports 13_1, 13_2 correspond to the first path 26_1 and the second path 26_2 described in the first embodiment, respectively. At this time, the output unit 12 outputs an optical transmission signal 22_1 in which a plurality of optical transmission signals are multiplexed to the transmission port 13_1. For example, when the output unit 12 outputs the optical transmission signals 21_1-21_5 to the transmission port 13_1, the optical transmission signal 22_1 in which the optical transmission signals 21_1-21_5 are multiplexed is supplied to the transmission port 13_1. Similarly, the output unit 12 outputs an optical transmission signal 22_2 in which a plurality of optical transmission signals are multiplexed to the transmission port 13_2. For example, when the output unit 12 outputs the optical transmission signals 21_6 to 21_10 to the transmission port 13_2, an optical transmission signal 22_2 in which the optical transmission signals 21_6 to 21_10 are multiplexed is supplied to the transmission port 13_2.

[0052] The output unit 12 can arbitrarily and dynamically switch between the optical transmission signals 21_1 to 21_m supplied to the respective transmission ports 13_1 and 13_2. For example, the output unit 12 is controlled by using a control means (not shown).

[0053] The multiple transmission ports 13_1, 13_2 are configured to be capable of transmitting optical transmission signals 22_1, 22_2 (in other words, optical transmission signals 21_1-21_m output from the output unit 12). That is, the transmission port 13_1 outputs an optical transmission signal 23_1 (same as the optical transmission signal 22_1) to a first optical receiving device (not shown) to which it is connected. Also, the transmission port 13_2 outputs an optical transmission signal 23_2 (same as the optical transmission signal 22_2) to a second optical receiving device (not shown) to which it is connected.

[0054] In the present embodiment, the optical transmitting device 1_2 is described as having two transmission ports 13_1 and 13_2. However, the number of transmission ports provided in the optical transmitting device 1_2 may be three or more. When the number of transmission ports is three or more, the output unit 12 can selectively output the optical transmission signals 21_1-21_m output from the plurality of subcarrier transmitting units 11_1-11_m to three or more transmission ports.

[0055] 5, the optical transmitting device according to the present embodiment is provided with a plurality of transmitting ports 13_1, 13_2 and an output unit 12, and the optical transmitting signals 21_1-21_m output from the plurality of subcarrier transmitting units 11_1-11_m are selectively output to the respective transmitting ports 13_1, 13_2 by using the output unit 12. Therefore, for example, when data is being transmitted to a first optical receiving device (not shown) via the transmitting port 13_1, if an unused subcarrier transmitting unit 11_m occurs, data can be transmitted to a second optical receiving device (not shown) via the transmitting port 13_2 by using the unused subcarrier transmitting unit 11_m.

[0056] In addition, by using the output unit 12 to dynamically switch the optical transmission signals 21_1 to 21_m supplied to each of the transmission ports 13_1 and 13_2, the transmission capacity in communication via the transmission port 13_1 and the transmission capacity in communication via the transmission port 13_2 can be dynamically adjusted.

[0057] According to the invention of the present embodiment described above, it is possible to provide an optical transmitting apparatus and an optical transmitting method capable of performing efficient resource allocation in an optical communication network.

[0058] <Embodiment 3> Next, a third embodiment of the present invention will be described. Fig. 8 is a block diagram showing an optical transmission device 1_3 according to the present embodiment. The optical transmission device 1_3 according to the present embodiment is different from the optical transmission device 1_2 described in the second embodiment in that it includes a light source 14, a subcarrier generation unit 15, and a signal conversion unit 16. Other than this, it is the same as the optical transmission device 1_2 described in the second embodiment, so the same components are given the same reference numerals and duplicated explanations will be omitted.

[0059] As shown in FIG. 8, an optical transmitting device 1_3 according to the present embodiment includes a plurality of subcarrier transmitting sections 11'_1 to 11'_m, an output section 12, transmission ports 13_1 and 13_2, a light source 14, a subcarrier generating section 15, and a signal converting section 16.

[0060] The light source 14 is a light source that outputs a single carrier C1 (light of a single wavelength) and can be configured using, for example, a laser diode. The carrier C1 generated by the light source 14 is output to the subcarrier generation unit 15.

[0061] Subcarrier generation unit 15 generates a plurality of subcarriers SC1 to SCm using carrier C1 generated by light source 14, and supplies each of the generated subcarriers SC1 to SCm to each of subcarrier transmitters 11'_1 to 11'_m. At this time, subcarrier generation unit 15 may generate a plurality of subcarriers SC1 to SCm by modulating carrier C1 generated by light source 14 using a predetermined modulation method.

[0062] For example, the subcarrier generation unit 15 may generate a plurality of subcarriers SC1 to SCm that are orthogonal to each other by modulating the carrier C1 generated by the light source 14 using an orthogonal frequency division multiplexing (OFDM) system. The subcarrier generation unit 15 may also generate a plurality of subcarriers SC1 to SCm using a Nyquist WDM system. In this way, by generating a plurality of subcarriers SC1 to SCm using the OFDM system or the Nyquist WDM system, the frequency interval can be narrowed down to the symbol rate interval, and the frequency utilization efficiency can be improved in communications using the super-channel technology.

[0063] For example, when subcarriers are generated using the light sources provided in the subcarrier transmitters 11_1-11_m (see embodiment 2), the intervals between the subcarriers SC1-SC4 become wider as shown in Fig. 9. On the other hand, when subcarriers are generated by modulating the carrier C1 generated by the light source 14 using the OFDM system as in this embodiment, the intervals between the subcarriers SC1-SC4 become narrower than those shown in Fig. 9 as shown in Fig. 10, and frequency utilization efficiency can be improved.

[0064] At this time, it is preferable that the intervals between the subcarriers SC1 to SCm are constant. In other words, when the wavelength intervals between the subcarriers SC1 to SCm vary, it is necessary to take into consideration the fluctuations in the wavelengths of the subcarriers SC1 to SCm, which reduces the frequency utilization efficiency. Therefore, in the optical transmission device 1_3 according to this embodiment, a single light source is used as the light source 14. This makes it possible to make the intervals between the subcarriers SC1 to SCm constant.

[0065] The signal conversion unit 16 performs serial-to-parallel conversion on the input transmission data DS1, DS2, and outputs the serial-to-parallel converted data DP1-DPm to the subcarrier transmission units 11'_1-11'_m, respectively. The subcarrier transmission unit 11'_1 generates an optical transmission signal 21_1 for transmitting the data DP1 using the subcarrier SC1. The subcarrier transmission unit 11'_2 generates an optical transmission signal 21_2 for transmitting the data DP2 using the subcarrier SC2. In this manner, the subcarrier transmission unit 11'_m generates an optical transmission signal 21_m for transmitting the data DPm using the subcarrier SCm.

[0066] Therefore, in the optical transmitting device 1_3 according to the present embodiment, the multiple subcarrier transmitting units 11'_1 to 11'_m can transmit the transmission data DP1 to DPm in parallel using the subcarriers SC1 to SCm corresponding to each of the subcarrier transmitting units 11'_1 to 11'_m.

[0067] That is, among the plurality of subcarrier transmitters 11'_1 to 11'_m, each subcarrier transmitter that transmits the optical transmission signal 22_1 via the transmission port 13_1 can transmit the first data in parallel, and among the plurality of subcarrier transmitters 11'_1 to 11'_m, each subcarrier transmitter that transmits the optical transmission signal 22_2 via the transmission port 13_2 can transmit the second data in parallel.

[0068] Specifically, for example, the optical transmitting device 1_3 includes subcarrier transmitters 11'_1-11'_10, and among these subcarrier transmitters 11'_1-11'_10, the subcarrier transmitters 11'_1-11'_6 transmit the first data DS1 via the transmission port 13_1. Also, the subcarrier transmitters 11'_7-11'_10 transmit the second data DS2 via the transmission port 13_2.

[0069] In this case, the signal conversion unit 16 performs serial-to-parallel conversion on the input first data DS1, and outputs the serial-to-parallel converted first data DP1-DP6 to the subcarrier transmission units 11'_1-11'_6, respectively. The subcarrier transmission units 11'_1-11'_6 generate optical transmission signals 21_1-21_6 for transmitting the first data DP1-DP6 using the subcarriers SC1-SC6, respectively. The output unit 12 outputs the generated optical transmission signals 21_1-21_6 to the transmission port 13_1. As a result, the multiplexed optical transmission signal 22_1 is output from the transmission port 13_1. Therefore, each of the subcarrier transmission units 11'_1-11'_6 can transmit the serial-to-parallel converted first data DS1 in parallel via the transmission port 13_1. At this time, the data width of the transmission data transmitted through the transmission port 13_1 corresponds to the number of the subcarrier transmitters 11'_1 to 11'_6 (that is, the data DP1 to DP6) connected to the transmission port 13_1.

[0070] Moreover, the signal conversion unit 16 performs serial-to-parallel conversion on the input second data DS2, and outputs the serial-to-parallel converted second data DP7-DP10 to the subcarrier transmission units 11'_7-11'_10, respectively. The subcarrier transmission units 11'_7-11'_10 generate optical transmission signals 21_7-21_10 for transmitting the second data DP7-DP10 using the subcarriers SC7-SC10, respectively. The output unit 12 outputs the generated optical transmission signals 21_7-21_10 to the transmission port 13_2. As a result, the multiplexed optical transmission signal 22_2 is output from the transmission port 13_2. Therefore, each of the subcarrier transmission units 11'_7-11'_10 can transmit the serial-to-parallel converted second data DS2 in parallel via the transmission port 13_2. At this time, the data width of the transmission data transmitted through the transmission port 13_2 corresponds to the number of subcarrier transmitters 11'_7 to 11'_10 (that is, data DP7 to DP10) connected to the transmission port 13_2.

[0071] The data width of the transmission data transmitted through the transmission port 13_1 and the data width of the transmission data transmitted through the transmission port 13_2 can be adjusted by using the output unit 12 to change the output destination of each of the optical transmission signals 21_1 to 21_m output from the multiple subcarrier transmission units 11'_1 to 11'_m.

[0072] The invention according to this embodiment can also provide an optical transmitting apparatus and an optical transmitting method capable of performing efficient resource allocation in an optical communication network.

[0073] <Fourth embodiment> Next, a fourth embodiment of the present invention will be described. Fig. 11 is a block diagram showing an optical transmission device 1_4 according to this embodiment. In the optical transmission device 1_4 according to this embodiment, a specific configuration example of the output unit 12 included in the optical transmission devices 1_1 to 1_3 described in the first to third embodiments is shown. Other than this, it is similar to the optical transmission devices 1_1 to 1_3 described in the first to third embodiments, so the same components are given the same reference numerals and duplicated explanations are omitted.

[0074] As shown in Fig. 11, an output unit 12_1 included in an optical transmitting device 1_4 according to the present embodiment includes a switching unit 30 and optical multiplexers 31_1 and 31_2. The switching unit 30 switches the output destination of the optical transmission signals 21_1-21_m output from each of the subcarrier transmitting units 11_1-11_m to either the optical multiplexer 31_1 or the optical multiplexer 31_2. The switching unit 30 can be configured using, for example, an optical matrix switch with m inputs and m x 2 outputs. Here, the m inputs of the switching unit 30 correspond to the number of the optical transmission signals 21_1-21_m. For example, the switching unit 30 is controlled using a control means (not shown).

[0075] A plurality of optical multiplexers 31_1, 31_2 are provided corresponding to the respective transmission ports 13_1, 13_2, and multiplex the respective optical transmission signals 21_1 to 21_m output from the switching unit 30. That is, the optical multiplexer 31_1 multiplexes and multiplexes the respective optical transmission signals output from the switching unit 30, and outputs the multiplexed optical transmission signal 22_1 to the transmission port 13_1. Similarly, the optical multiplexer 31_2 multiplexes and multiplexes the respective optical transmission signals output from the switching unit 30, and outputs the multiplexed optical transmission signal 22_2 to the transmission port 13_2.

[0076] In this manner, in the optical transmitting device 1_4 according to the present embodiment, the output unit 12_1 is configured using the switching unit 30 and the optical multiplexers 31_1 and 31_2. Therefore, the optical transmission signals 21_1 to 21_m supplied to the respective transmission ports 13_1 and 13_2 can be dynamically switched.

[0077] The switching unit 30 may be configured using a plurality of optical switches SW_1-SW_m, like the output unit 12_2 included in the optical transmitting device 1_5 shown in Fig. 12. In this case, the plurality of optical switches SW_1-SW_m are provided corresponding to the respective subcarrier transmitting units 11_1-11_m, and switch the output destination of the optical transmission signals 21_1-21_m outputted from the respective subcarrier transmitting units 11_1-11_m to the optical multiplexer 31_1 or the optical multiplexer 31_2.

[0078] For example, the optical switch SW_1 is provided corresponding to the subcarrier transmitter 11_1, and outputs the optical transmission signal 21_1 output from the subcarrier transmitter 11_1 to either the optical multiplexer 31_1 or the optical multiplexer 31_2. The optical switch SW_2 is provided corresponding to the subcarrier transmitter 11_2, and outputs the optical transmission signal 21_2 output from the subcarrier transmitter 11_2 to either the optical multiplexer 31_1 or the optical multiplexer 31_2. Each of the optical switches SW_1 to SW_m is controlled by using a control means (not shown).

[0079] 13, the output unit may be configured using an optical multiplexer 32 and an optical demultiplexer 33. In this case, the optical multiplexer 32 multiplexes and multiplexes the optical transmission signals 21_1-21_m output from the subcarrier transmitters 11_1-11_m, and outputs the multiplexed optical signal 25 to the optical demultiplexer 33. The optical demultiplexer 33 selectively outputs the optical transmission signals 21_1-21_m included in the multiplexed optical signal 25 output from the optical multiplexer 32 to the transmission ports 13_1 and 13_2.

[0080] For example, the optical demultiplexer 33 outputs the optical transmission signal 21_1 included in the multiplexed optical signal 25 to either the transmission port 13_1 or the transmission port 13_2. Also, the optical demultiplexer 33 outputs the optical transmission signal 21_2 included in the multiplexed optical signal 25 to either the transmission port 13_1 or the transmission port 13_2.

[0081] For example, the optical demultiplexer 33 may selectively output each of the optical transmission signals 21_1 to 21_m included in the multiplexed optical signal 25 to the transmission ports 13_1 and 13_2 according to the wavelength.

[0082] <Embodiment 5> Next, a fifth embodiment of the present invention will be described. Fig. 14 is a block diagram showing an optical receiving device 2_1 according to the fifth embodiment. As shown in Fig. 14, the optical receiving device 2_1 according to the present embodiment includes a switching unit 42, a first receiving unit 43_1, and a second receiving unit 43_2. In the following, the first and second receiving units may also be referred to as subcarrier receiving units.

[0083] The switching unit 42 receives the input optical reception signals 51_1 and 51_2, and selectively outputs the subcarrier reception signals 52_1 and 52_2 contained therein to the first reception unit 43_1 and the second reception unit 43_2. In other words, the switching unit 42 can arbitrarily and dynamically switch the output destinations (the first and second reception units 43_1 and 43_2) of the subcarrier reception signals contained in the optical reception signals 51_1 and 51_2. For example, the switching unit 42 is controlled using a control means (not shown).

[0084] The first receiving unit 43_1 receives data transmitted using the subcarrier reception signal 52_1. The second receiving unit 43_2 receives data transmitted using the subcarrier reception signal 52_2. The first receiving unit 43_1 and the second receiving unit 43_2 each include a detection unit (not shown) for detecting the subcarrier reception signals 52_1 and 52_2. Each detection unit may include a local oscillator.

[0085] In the optical receiving device 2_1 according to the present embodiment, when the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 share a series of information, the switching unit 42 receives the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 via the same path. For example, the switching unit 42 can receive the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 via the same path by receiving an optical reception signal 51_1 including the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2. At this time, the switching unit 42 outputs the first subcarrier reception signal 52_1 to the first receiving unit 43_1 and the second subcarrier reception signal 52_2 to the second receiving unit 43_2.

[0086] On the other hand, when the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 do not share a series of information, the switching unit 42 receives the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 via different paths. For example, when the optical reception signal 51_1 includes the first subcarrier reception signal 52_1 and the optical reception signal 51_2 includes the second subcarrier reception signal 52_2, the switching unit 42 can receive the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 via different paths by receiving the optical reception signal 51_1 and the optical reception signal 51_1. At this time, the switching unit 42 outputs the first subcarrier reception signal to the first reception unit 43_1 and outputs the second subcarrier reception signal to the second reception unit 43_2.

[0087] Here, a case in which the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 share a series of information is, for example, a case in which predetermined data is transmitted in parallel using the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2.

[0088] On the other hand, a case where the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 do not share a series of information is, for example, a case where the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 transmit predetermined data independently. For example, a first optical transmission device (not shown) transmits first data using the first subcarrier reception signal 52_1, and a second optical transmission device (not shown) transmits second data using the second subcarrier reception signal 52_2. At this time, the optical reception device 2_1 receives the first subcarrier reception signal 52_1 transmitted from the first optical transmission device (not shown) via the first route, and receives the second subcarrier reception signal 52_2 transmitted from the second optical transmission device (not shown) via the second route.

[0089] In this manner, in the optical receiving device 2_1 according to the present embodiment, the first subcarrier reception signal 52_1 and the second subcarrier reception signal 52_2 are selectively output to the first receiving section 43_1 and the second receiving section 43_2 by using the switching section 42.

[0090] Therefore, for the same reasons as those explained in the first embodiment, it is possible to provide an optical receiving device and an optical receiving method capable of performing efficient resource allocation in an optical communication network.

[0091] <Sixth embodiment> Next, a sixth embodiment of the present invention will be described. Fig. 15 is a block diagram showing an optical receiving device 2_2 according to the sixth embodiment. In the sixth embodiment, a detailed configuration of the optical receiving device 2_1 described in the fifth embodiment will be described. As shown in Fig. 15, the optical receiving device 2_2 according to the present embodiment includes a plurality of receiving ports 41_1, 41_2, a switching unit 42, subcarrier receiving units 43_1 to 43_m, and a signal processing unit 45.

[0092] The multiple reception ports (PR_1, PR_2) 41_1, 41_2 respectively receive the multiplexed optical reception signals 50_1, 50_2 supplied to the optical receiving device 2_2, and output the received optical reception signals 51_1, 51_2 to the switching unit 42. The reception ports 41_1, 41_2 can respectively receive the optical reception signals 50_1, 50_2 transmitted from different optical transmitting devices. For example, the reception port 41_1 can receive the optical reception signal 50_1 transmitted from a first optical transmitting device (not shown), and the reception port 41_2 can receive the optical reception signal 50_2 transmitted from a second optical transmitting device (not shown).

[0093] The switching unit 42 selectively outputs each of the subcarrier reception signals 52_1-52_m included in each of the optical reception signals 51_1, 51_2 received at the multiple reception ports 41_1, 41_2 to a plurality of subcarrier reception units (SCR_1-SCR_m) 43_1-43_m. In other words, each of the multiplexed optical reception signals 51_1, 51_2 is separated into each of the subcarrier reception signals 52_1-52_m by the switching unit 42. Then, each of the separated subcarrier reception signals 52_1-52_m is output to each of the subcarrier reception units 43_1-43_m corresponding to each of the subcarrier reception signals 52_1-52_m (i.e., subcarrier reception units capable of receiving subcarrier reception signals of each wavelength). At this time, one subcarrier reception signal 52_m is input to one subcarrier reception unit 43_m.

[0094] The switching unit 42 can arbitrarily and dynamically switch the output destinations (subcarrier receiving units 43_1 to 43_m) of the respective subcarrier reception signals 52_1 to 52_m. For example, the switching unit 42 is controlled by using a control means (not shown).

[0095] The subcarrier receiving unit 43_1 receives data transmitted using the subcarrier reception signal 52_1. The subcarrier receiving unit 43_2 receives data transmitted using the subcarrier reception signal 52_2. In this manner, the subcarrier receiving unit 43_m receives each data transmitted using the subcarrier reception signal 52_m. Each of the subcarrier receiving units 43_1-43_m includes a detection unit (not shown) for detecting each of the subcarrier reception signals 52_1-52_m. Each detection unit may include a local oscillator. That is, each of the subcarrier receiving units 43_1-43_m can receive the subcarrier reception signals 52_1-52_m corresponding to each of the subcarrier receiving units 43_1-43_m by causing interference between the local oscillation light generated by each of the local oscillators and each of the input subcarrier reception signals 52_1-52_m.

[0096] Each of the subcarrier reception signals 52_1 to 52_m may be modulated using a predetermined modulation method. In this case, the subcarrier reception units 43_1 to 43_m include a circuit for reading data from the subcarrier reception signals 52_1 to 52_m modulated by the predetermined modulation method. Examples of the predetermined modulation method include amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), quadrature amplitude modulation (QAM), and quadrature phase shift keying (QPSK). As the quadrature amplitude modulation (QAM), for example, 16QAM, 64QAM, 128QAM, 256QAM, etc. can be used.

[0097] Moreover, in the optical receiving device 2_2 according to the present embodiment, each of the subcarrier receiving units 43_1-43_m that receives a subcarrier reception signal (optical reception signal 50_1) via the reception port 41_1 can receive the serial-parallel converted first data in parallel. Moreover, each of the subcarrier receiving units 43_1-43_m that receives a subcarrier reception signal (optical reception signal 50_2) via the second reception port 41_2 can receive the serial-parallel converted second data in parallel. In other words, each of the subcarrier reception signals included in the optical reception signal 50_1 received via the reception port 41_1 shares a series of information. Moreover, each of the subcarrier reception signals included in the optical reception signal 50_2 received via the reception port 41_2 shares a series of information.

[0098] Specifically, for example, the optical receiving device 2_2 includes subcarrier receiving units 43_1-43_10, and among these subcarrier receiving units 43_1-43_10, the subcarrier receiving units 43_1-43_6 receive the first data via the receiving port 41_1. Also, the subcarrier receiving units 43_7-43_10 receive the second data via the receiving port 41_2.

[0099] In this case, the optical receiving device 2_2 receives the optical receiving signal 50_1 transmitted from the first optical transmitting device (not shown) via the receiving port 41_1. Then, the subcarrier receiving units 43_1-43_6 receive the subcarrier receiving signals 52_1-52_6 included in the optical receiving signal 50_1, respectively, to receive the first data (data serial-parallel converted by the first optical transmitting device) in parallel. The first data thus transmitted in parallel can be converted into serial data by the signal processing unit 45 at the subsequent stage.

[0100] Similarly, the optical receiving device 2_2 receives an optical receiving signal 50_2 transmitted from a second optical transmitting device (not shown) via the receiving port 41_2. Then, the subcarrier receiving units 43_7-43_10 receive the subcarrier receiving signals 52_7-52_10 included in the optical receiving signal 50_2, respectively, to receive the second data (data serial-parallel converted by the second optical transmitting device) in parallel. The second data thus transmitted in parallel can be converted into serial data by the signal processing unit 45 at the subsequent stage.

[0101] For example, each of the subcarrier receiving units 43_1 to 43_m includes an opto-electrical converter (not shown). Each of the opto-electrical converters converts the subcarrier receiving signals 52_1 to 52_m into an electric signal, and outputs the electric signal as the receiving signals 53_1 to 53_m to the signal processing unit 45. For example, a photodiode can be used as the opto-electrical converter.

[0102] The signal processing unit 45 performs a predetermined process on the reception signals 53_1-53_m output from the subcarrier reception units 43_1-43_m to generate data. The signal processing unit 45 may also compensate for the influence of mutual interference between the subcarrier reception signals 52_1-52_m. That is, the signal processing unit 45 simultaneously processes the subcarrier reception units 43_1-43_m, thereby making it possible to compensate for, for example, crosstalk and nonlinear optical effects (such as cross phase modulation (XPM) and four wave mixing (FWM)). For example, the signal processing unit 45 may compensate for the influence of mutual interference between the subcarrier reception signals 52_1-52_m by controlling the local oscillators of the subcarrier reception units 43_1-43_m in accordance with the subcarrier reception signals 52_1-52_m.

[0103] In the super-channel technology, multiple wavelengths (subcarriers) are used in one channel band, and the wavelengths are multiplexed at high density. This causes a large effect of mutual interference between subcarriers. In the optical receiving device according to this embodiment, multiple different subcarriers are received by the same optical receiving device, and adjacent subcarriers that affect one subcarrier can be simultaneously monitored. This makes it possible to set compensation parameters for compensating for the effect of mutual interference between subcarrier reception signals.

[0104] In the present embodiment, the optical receiving device 2_2 is provided with two receiving ports 41_1 and 41_2. However, the number of receiving ports provided in the optical receiving device 2_2 may be three or more.

[0105] As in the case described in the first embodiment, when an optical receiving device has only one receiving port, the following problem occurs. That is, when an optical receiving device receives data from a first optical transmitting device (not shown) via one receiving port, if an unused subcarrier receiving unit occurs, this unused subcarrier receiving unit cannot be used, resulting in a problem of wasting resources. That is, when there is only one receiving port, the unused subcarrier receiving unit cannot be used to receive data from another optical transmitting device, resulting in a problem of wasting the unused subcarrier receiving unit.

[0106] 15, the optical receiver 2_2 according to the present embodiment is provided with a plurality of reception ports 41_1, 41_2 and a switching unit 42, and the switching unit 42 is used to selectively output each of the subcarrier reception signals 52_1-52_m included in each of the optical reception signals 51_1, 51_2 received at the plurality of reception ports 41_1, 41_2 to a plurality of subcarrier reception units 43_1-43_m. Therefore, for example, when an unused subcarrier reception unit occurs, an optical reception signal can be received from another optical transmitter (not shown) via an available reception port, and data can be received in the unused subcarrier reception unit using this optical reception signal.

[0107] In the above description, a case where one subcarrier reception signal 52_m is input to one subcarrier reception unit 43_m has been described, but the optical receiving device 2_2 according to the present embodiment may be configured such that a plurality of subcarrier reception signals are input to one subcarrier reception unit 43_m, and the plurality of subcarrier reception signals are selectively received by one subcarrier reception unit 43_m. In this case, a local oscillator (not shown) is provided in each of the subcarrier reception units 43_1 to 43_m, and a specific subcarrier reception signal (i.e., a subcarrier reception signal corresponding to a specific wavelength) can be selectively received from among the plurality of subcarrier reception signals by interfering with a local oscillation light of a specific wavelength output from the local oscillator and the plurality of input subcarrier reception signals (multiplexed subcarrier reception signals). In this way, the configuration of the switching unit 42 can be simplified by allowing a plurality of subcarrier reception signals to be input to one subcarrier reception unit 43_m.

[0108] According to the invention of the present embodiment described above, it is possible to provide an optical receiving device and an optical receiving method capable of performing efficient resource allocation in an optical communication network.

[0109] <Embodiment 7> Next, a seventh embodiment of the present invention will be described. Fig. 16 is a block diagram showing an optical receiving device 2_3 according to this embodiment. The optical receiving device 2_3 according to this embodiment differs from the optical receiving device 2_2 according to the sixth embodiment in that a local oscillator (LO) is shared by a plurality of subcarrier receiving units. Other than this, it is similar to the optical receiving device 2_2 described in the sixth embodiment, so the same components are given the same reference numerals and duplicated explanations will be omitted.

[0110] As shown in FIG. 16, the optical receiving device 2_3 according to the present embodiment includes a plurality of receiving ports 41_1, 41_2, a switching unit 42, subcarrier receiving units 43_1 to 43_6, local oscillators 44_1, 44_2, and a signal processing unit 45. In the optical receiving device 2_3 according to the present embodiment, a plurality of subcarrier receiving units share a local oscillator. That is, a plurality of subcarrier receiving units 43_1 to 43_3 share a local oscillator 44_1. Also, a plurality of subcarrier receiving units 43_4 to 43_6 share a local oscillator 44_2. In the example shown in FIG. 16, the number of subcarrier receiving units is 6 (m=6), but the number of subcarrier receiving units may be other than this. In this case, the number of local oscillators can be increased according to the number of subcarrier receiving units. In addition, while the example shown in FIG. 16 shows an example in which one local oscillator is shared by three subcarrier receiving units, the number of subcarrier receiving units sharing one local oscillator may be two, or may be four or more.

[0111] The switching unit 42 selectively outputs each of the subcarrier reception signals 52_1 to 52_6 included in each of the optical reception signals 51_1 and 51_2 received at the multiple reception ports 41_1 and 41_2 to the multiple subcarrier reception units 43_1 to 43_6. In other words, each of the multiplexed optical reception signals 51_1 and 51_2 is separated into each of the subcarrier reception signals 52_1 to 52_6 by the switching unit 42. Then, each of the separated subcarrier reception signals 52_1 to 52_6 is output to each of the subcarrier reception units 43_1 to 43_6 corresponding to each of the subcarrier reception signals 52_1 to 52_6. At this time, one subcarrier reception signal is input to one subcarrier reception unit.

[0112] The switching unit 42 can arbitrarily and dynamically switch the output destination of each of the subcarrier reception signals 52_1 to 52_6. For example, the switching unit 42 is controlled by using a control means (not shown).

[0113] The subcarrier receiving units 43_1 to 43_6 receive the respective data transmitted using the respective subcarrier reception signals 52_1 to 52_6. Each of the subcarrier receiving units 43_1 to 43_6 includes a detection unit (not shown) for detecting each of the subcarrier reception signals 52_1 to 52_6. At this time, the detection unit included in each of the subcarrier receiving units 43_1 to 43_6 can perform detection using the local oscillation light output from the local oscillators 44_1 and 44_2.

[0114] That is, the subcarrier receiving units 43_1 to 43_3 can detect the respective subcarrier receiving signals 52_1 to 52_3 using the local oscillation light output from the local oscillator 44_1. At this time, the local oscillator 44_1 generates local oscillation light having a wavelength corresponding to each of the subcarrier receiving signals 52_1 to 52_3 (a wavelength that interferes with each of the subcarrier receiving signals 52_1 to 52_3). That is, when the wavelengths of the subcarrier receiving signals 52_1 to 52_3 are close to each other, even if the local oscillation light output from the local oscillator 44_1 has a single wavelength, each of the subcarrier receiving signals 52_1 to 52_3 interferes with the local oscillation light. Therefore, each of the subcarrier receiving units 43_1 to 43_3 can detect the respective subcarrier receiving signals 52_1 to 52_3 using the local oscillation light output from the local oscillator 44_1.

[0115] Similarly, the subcarrier receiving units 43_4-43_6 can detect the subcarrier reception signals 52_4-52_6 by using the local oscillation light output from the local oscillator 44_2. At this time, the local oscillator 44_2 generates local oscillation light having a wavelength corresponding to each of the subcarrier reception signals 52_4-52_6 (a wavelength that interferes with each of the subcarrier reception signals 52_4-52_6). That is, when the wavelengths of the subcarrier reception signals 52_4-52_6 are close to each other, even if the local oscillation light output from the local oscillator 44_2 is a local oscillation light having a single wavelength, each of the subcarrier reception signals 52_4-52_6 interferes with the local oscillation light. Therefore, each of the subcarrier receiving units 43_4-43_6 can detect the subcarrier reception signals 52_4-52_6 by using the local oscillation light output from the local oscillator 44_2. For example, the local oscillators 44_1 and 44_2 can be configured using laser diodes.

[0116] For example, each of the subcarrier receiving units 43_1 to 43_6 includes an opto-electrical converter (not shown). Each of the opto-electrical converters converts the subcarrier receiving signals 52_1 to 52_6 into an electric signal, and outputs the electric signal as the receiving signals 53_1 to 53_6 to the signal processing unit 45. For example, a photodiode can be used as the opto-electrical converter.

[0117] The signal processing unit 45 performs a predetermined process on the reception signals 53_1 to 53_6 output from the subcarrier reception units 43_1 to 43_6 to generate data. The signal processing unit 45 can also control the local oscillators 44_1 and 44_2 in response to the reception signals 53_1 to 53_6 output from the subcarrier reception units 43_1 to 43_6. In other words, the local oscillators 44_1 and 44_2 are controlled in response to the subcarrier reception signals 52_1 to 52_6 included in the optical reception signals 51_1 and 51_2.

[0118] For example, when the optical reception signals 51_1 and 51_2 do not include subcarrier reception signals corresponding to the subcarrier reception units, the signal processing unit 45 may turn off a local oscillator shared by the subcarrier reception units. To be more specific, when the optical reception signals 51_1 and 51_2 do not include all of the subcarrier reception signals 52_1 to 52_3 corresponding to the subcarrier reception units 43_1 to 43_3, the signal processing unit 45 can turn off the local oscillator 44_1 shared by the subcarrier reception units 43_1 to 43_3. Similarly, when the optical reception signals 51_1 and 51_2 do not include all of the subcarrier reception signals 52_4 to 52_6 corresponding to the subcarrier reception units 43_4 to 43_6, the signal processing unit 45 can turn off the local oscillator 44_2 shared by the subcarrier reception units 43_4 to 43_6. By such control, unnecessary local oscillators can be turned off, and the power consumption of the optical receiving device 2_3 can be reduced.

[0119] Also, as in the sixth embodiment, multiple subcarrier reception signals can be processed simultaneously in the signal processing unit 45, thereby making it possible to compensate for, for example, crosstalk and nonlinear optical effects (such as cross-phase modulation (XPM) and four-wave mixing (FWM)).

[0120] According to the invention of the present embodiment described above, it is possible to provide an optical receiving device and an optical receiving method capable of performing efficient resource allocation in an optical communication network.

[0121] <Embodiment 8> Next, an eighth embodiment of the present invention will be described. Fig. 17 is a block diagram showing an optical receiving device 2_4 according to this embodiment. In the optical receiving device 2_4 according to this embodiment, a specific configuration example of the switching unit 42 included in the optical receiving devices 2_1 to 2_3 described in the fifth to seventh embodiments is shown. Other than this, it is similar to the optical receiving devices 2_1 to 2_3 described in the fifth to seventh embodiments, so the same components are given the same reference numerals and duplicated explanations are omitted.

[0122] 17, the switching unit 42_1 included in the optical receiving device 2_4 according to the present embodiment includes optical branching devices 60_1 and 60_2 and an optical changeover switch 61. The optical branching devices 60_1 and 60_2 are provided corresponding to the receiving ports 41_1 and 41_2, respectively, and branch the optical receiving signals 51_1 and 51_2 received at the receiving ports 41_1 and 41_2, respectively, and output the branched optical receiving signals to the optical changeover switch 61.

[0123] The optical changeover switch 61 receives the optical reception signals branched by each of the optical branchers 60_1, 60_2 and selectively outputs the signals to each of the subcarrier receiving units 43_1-43_m. For example, the optical changeover switch 61 can be configured using an optical matrix switch with m×2 inputs and m outputs. Here, the m outputs of the optical changeover switch 61 correspond to the number of the subcarrier receiving units 43_1-43_m. For example, the optical changeover switch 61 is controlled using a control means (not shown).

[0124] As described above, in the optical receiving device 2_4 according to the present embodiment, the switching unit 42_1 is configured using the optical branching devices 60_1 and 60_2 and the optical changeover switch 61. Therefore, the subcarrier reception signals 52_1-52_m supplied to the respective subcarrier receiving units 43_1-43_m can be dynamically switched.

[0125] The optical changeover switch 61 may be configured using a plurality of optical switches SW_1-SW_m, like the switching unit 42_2 included in the optical receiving device 2_5 shown in Fig. 18. In this case, the optical switches SW_1-SW_m are provided corresponding to the respective subcarrier receiving units 43_1-43_m, and select and output optical receiving signals to be output to the respective subcarrier receiving units 43_1-43_m from the optical receiving signals branched by the respective optical branchers 60_1, 60_2.

[0126] For example, the optical switch SW_1 is provided to correspond to the subcarrier receiver 43_1, and selects a subcarrier reception signal 52_1 corresponding to the subcarrier receiver 43_1 from among the optical reception signals branched by the optical branchers 60_1 and 60_2, and outputs the selected subcarrier reception signal 52_1 to the subcarrier receiver 43_1. The optical switch SW_2 is provided to correspond to the subcarrier receiver 43_2, and selects a subcarrier reception signal 52_2 corresponding to the subcarrier receiver 43_2 from among the optical reception signals branched by the optical branchers 60_1 and 60_2, and outputs the selected subcarrier reception signal 52_2 to the subcarrier receiver 43_2. Each of the optical switches SW_1 to SW_m is controlled by a control means (not shown). For example, the optical switches SW_1 to SW_m can be configured by a wavelength selection type optical switch.

[0127] Also, for example, as in the optical receiving device described in the latter half of the sixth embodiment, if each of the subcarrier receiving units 43_1 to 43_m can selectively receive a specific subcarrier receiving signal, multiple subcarrier receiving signals may be input to one subcarrier receiving unit 43_m. In this case, for example, each of the optical switches SW_1 to SW_m can output multiple subcarrier receiving signals to one subcarrier receiving unit 43_m.

[0128] The switching unit may be configured using an optical multiplexer 62 and an optical demultiplexer 63, like the switching unit 42_3 included in the optical receiving device 2_6 shown in Fig. 19. The optical multiplexer 62 multiplexes and multiplexes the optical receiving signals 51_1 and 51_2 received at the receiving ports 41_1 and 41_2, and outputs the multiplexed optical signal 64 to the optical demultiplexer 63. The optical demultiplexer 63 selectively outputs each of the subcarrier receiving signals 52_1 to 52_m included in the multiplexed optical signal 64 to each of the subcarrier receiving units 43_1 to 43_m.

[0129] That is, the optical demultiplexer 63 outputs the subcarrier reception signal 52_1 included in the multiplexed optical signal 64 to the subcarrier reception unit 43_1. Also, the optical demultiplexer 63 outputs the subcarrier reception signal 52_2 included in the multiplexed optical signal 64 to the subcarrier reception unit 43_2.

[0130] For example, the optical demultiplexer 63 can selectively output each of the subcarrier reception signals 52_1-52_m included in the multiplexed optical signal 64 to the subcarrier reception units 43_1-43_m according to the wavelength. In this case, the optical demultiplexer 63 can be configured using a wavelength selection type optical demultiplexer 63.

[0131] Also, as in the optical receiving device described in the latter half of the sixth embodiment, if each of the subcarrier receiving units 43_1 to 43_m can selectively receive a specific subcarrier receiving signal, a plurality of subcarrier receiving signals may be input to one subcarrier receiving unit 43_m. In this case, for example, the optical demultiplexer 62 can output a plurality of subcarrier receiving signals included in the multiplexed optical signal 63 to one subcarrier receiving unit 43_m. For example, an optical splitter may be used instead of the optical demultiplexer 63.

[0132] <Embodiment 9> Next, a ninth embodiment of the present invention will be described. Fig. 20 is a block diagram showing an optical communication device 3 according to this embodiment. The optical communication device 3 according to this embodiment is an optical communication device capable of transmitting and receiving, and is configured by combining the optical transmitting device 1_1 described in the first embodiment and the optical receiving device 2_1 described in the fifth embodiment.

[0133] As shown in Fig. 20, the optical communication device 3 according to the present embodiment includes a first transmitting section 11_1, a second transmitting section 11_2, an output section 12, a switching section 42, a first receiving section 43_1, and a second receiving section 43_2. An optical transmission signal 22_1 and an optical reception signal 51_1 are configured to be capable of being transmitted and received via a first path. An optical transmission signal 22_2 and an optical reception signal 51_2 are configured to be capable of being transmitted and received via a second path.

[0134] The configurations and operations of the first transmitting unit 11_1, the second transmitting unit 11_2, and the output unit 12 are similar to those of the optical transmitting device 1_1 described in the embodiment 1, and therefore will not be described again. The configurations and operations of the switching unit 42, the first receiving unit 43_1, and the second receiving unit 43_2 are similar to those of the optical receiving device 2_1 described in the embodiment 5, and therefore will not be described again.

[0135] In addition, in the optical communication device 3 according to this embodiment, the configurations of the optical transmitting devices 1_2 to 1_6 described in the second to fourth embodiments may be applied, and the configurations of the optical receiving devices 2_2 to 2_6 described in the sixth to eighth embodiments may be applied.

[0136] According to the invention of the present embodiment described above, it is possible to provide an optical communication device and an optical communication method capable of performing efficient resource allocation in an optical communication network.

[0137] <Embodiment 10> Next, a tenth embodiment of the present invention will be described. Fig. 21 is a block diagram showing an optical communication system according to this embodiment. As shown in Fig. 21, the optical communication system according to this embodiment includes an optical transmitting device 1 and optical receiving devices 70_1 and 70_2 that communicate with the optical transmitting device 1. The optical transmitting devices 1_1 to 1_6 described in the first to fourth embodiments can be used for the optical transmitting device 1.

[0138] The optical transmitting device 1 includes a plurality of subcarrier transmitting units 11_1-11_m, an output unit 12, and transmission ports 13_1 and 13_2. The plurality of subcarrier transmitting units 11_1-11_m generate optical transmission signals 21_1-21_m for transmitting data using subcarriers, respectively. The output unit 12 selectively outputs each of the optical transmission signals 21_1-21_m output from the plurality of subcarrier transmitting units 11_1-11_m to the transmission port 13_1 or the transmission port 13_2. Note that the configuration and operation of the optical transmitting device 1 are similar to those of the optical transmitting devices 1_1-1_6 described in the first to fourth embodiments, and therefore repeated description will be omitted.

[0139] The transmission port 13_1 is connected to a reception port 71_1 of the optical receiving device 70_1 via an optical fiber, and the transmission port 13_2 is connected to a reception port 71_2 of the optical receiving device 70_2 via an optical fiber. The optical transmitting device 1 transmits an optical transmission signal 23_1 to the optical receiving device 70_1 via the transmission port 13_1. The optical transmitting device 1 transmits an optical transmission signal 23_2 to the optical receiving device 70_2 via the transmission port 13_2. The optical transmission signal 23_1 is a signal in which a plurality of optical transmission signals 21_m are multiplexed. The receiving unit 72_1 included in the optical receiving device 70_1 is configured to be able to receive such a multiplexed optical transmission signal. Similarly, the optical transmission signal 23_2 is a signal in which a plurality of optical transmission signals 21_m are multiplexed. The receiving unit 72_2 included in the optical receiving device 70_2 is configured to be able to receive such a multiplexed optical transmission signal.

[0140] Among the plurality of subcarrier transmitters 11_1 to 11_m, each of the subcarrier transmitters that transmits an optical transmission signal via the transmission port 13_1 may transmit the serial-to-parallel converted first data in parallel to the optical receiving device 70_1. Also, among the plurality of subcarrier transmitters 11_1 to 11_m, each of the subcarrier transmitters that transmits an optical transmission signal via the transmission port 13_2 may transmit the serial-to-parallel converted second data in parallel to the optical receiving device 70_2.

[0141] That is, the optical transmitting device 1 serial-to-parallel converts the first data to be transmitted to the optical receiving device 70_1, generates optical transmission signals for transmitting each of the serial-to-parallel converted data in a subcarrier transmitting unit, and transmits the optical transmission signals to the optical receiving device 70_1. The optical receiving device 70_1 receives the serial-to-parallel converted data included in the optical transmission signal 23_1, and performs parallel-to-serial conversion on the received serial-to-parallel converted data, thereby obtaining the parallel-to-serial converted first data. The same applies to the second data transmitted to the optical receiving device 70_2.

[0142] In the optical communication system according to the present embodiment, the transmission capacity between the optical transmitter 1 and the optical receiver 70_1 is determined based on the number of the subcarrier transmitters 11_1-11_m that output the optical transmission signal to the transmission port 13_1. Similarly, the transmission capacity between the optical transmitter 1 and the optical receiver 70_2 is determined based on the number of the subcarrier transmitters 11_1-11_m that output the optical transmission signal to the transmission port 13_2. In other words, the ratio of the transmission capacity of the optical transmission signal 23_1 to the transmission capacity of the optical transmission signal 23_2 corresponds to the ratio of the number of the subcarrier transmitters connected to the transmission port 13_1 to the number of the subcarrier transmitters connected to the transmission port 13_2. For example, when increasing the transmission capacity between the optical transmitter 1 and the optical receiver 70_1, the output unit 12 is controlled to increase the number of the subcarrier transmitters connected to the transmission port 13_1.

[0143] Also, a subcarrier in a first wavelength band may be used for transmission between the optical transmitting device 1 and the optical receiving device 70_1, and a subcarrier in a second wavelength band may be used for transmission between the optical transmitting device 1 and the optical receiving device 70_2. Here, the first wavelength band and the second wavelength band are bands in which the wavelengths do not overlap with each other. For example, these wavelength bands are the C band, L band, S band, etc. used in WDM.

[0144] The setting of the communication between the optical transmitting device 1 and the optical receiving device 70_1 may be determined according to at least one of the distance between the optical transmitting device 1 and the optical receiving device 70_1, the time period during which the communication is performed, and the state of the transmission path between the optical transmitting device 1 and the optical receiving device 70_1. The setting of the communication between the optical transmitting device 1 and the optical receiving device 70_1 may be determined using at least one of the allocation of the wavelength band of the subcarrier in the communication between the optical transmitting device 1 and the optical receiving device 70_1, the path of the optical signal, and the modulation method. The same applies to the setting of the communication between the optical transmitting device 1 and the optical receiving device 70_2.

[0145] For example, as the communication distance between the optical transmitting device 1 and the optical receiving device 70_1 becomes longer, the multi-level degree per subcarrier may be decreased and the number of subcarriers may be increased. Conversely, as the communication distance between the optical transmitting device 1 and the optical receiving device 70_1 becomes shorter, the multi-level degree per subcarrier may be increased and the number of subcarriers may be decreased.

[0146] To explain this in detail, taking the case of using quadrature amplitude modulation (QAM) as an example, if the communication distance between the optical transmitter 1 and the optical receiver 70_1 is long, increasing the multilevel level per subcarrier using a modulation method such as 128QAM or 256QAM increases the bit error rate. Therefore, in this case, the multilevel level per subcarrier is reduced by using a modulation method such as 16QAM or 64QAM. In addition, since the amount of information contained in one subcarrier is reduced in this case, the number of subcarriers is increased accordingly.

[0147] On the other hand, when the communication distance between the optical transmitter 1 and the optical receiver 70_1 is short, the multilevel degree per subcarrier can be increased by using a modulation method such as 128QAM or 256QAM. In this case, the amount of information contained in one subcarrier can be increased, and therefore the number of subcarriers can be reduced accordingly.

[0148] Also, for example, when the transmission path between the optical transmitter 1 and the optical receiver 70_1 is deteriorated (when tension acts on the optical fiber, etc.), for example, the multilevel degree per subcarrier may be reduced. By reducing the multilevel degree per subcarrier in this way, it is possible to suppress an increase in the bit error rate.

[0149] Incidentally, the communication arrangement in the optical communication system as described above can be determined by the optical transmitting device 1 and the optical receiving devices 70_1, 70_1.

[0150] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a method for controlling the optical communication system that can perform efficient resource allocation in an optical communication network.

[0151] <Embodiment 11> Next, an eleventh embodiment of the present invention will be described. FIG. 22 is a block diagram showing an optical communication system according to this embodiment. As shown in FIG. 22, the optical communication system according to this embodiment includes an optical transmission device 1, optical reception devices 70_1 and 70_2 that communicate with the optical transmission device 1, and a controller 80. Note that the optical communication system according to this embodiment is similar to the optical communication system described in the tenth embodiment except for the inclusion of the controller 80, so duplicated explanations will be omitted. Also in this embodiment, the optical transmission devices 1_1 to 1_6 described in the first to fourth embodiments can be used as the optical transmission device 1.

[0152] The controller 80 is provided to control the optical transmitting device 1 and the optical receiving devices 70_1 and 70_2, respectively. That is, the controller 80 can control the optical transmitting device 1 and the optical receiving devices 70_1 and 70_2 according to the communication state between the optical transmitting device 1 and the optical receiving device 70_1 and the communication state between the optical transmitting device 1 and the optical receiving device 70_2.

[0153] Fig. 23 is a block diagram showing a configuration example of the controller 80. As shown in Fig. 23, the controller 80 includes a monitoring unit 81 and a setting unit 82. The monitoring unit 81 monitors the communication state of the optical communication system, that is, the communication state between the optical transmitting device 1 and the optical receiving device 70_1 and the communication state between the optical transmitting device 1 and the optical receiving device 70_2. The setting unit 82 sets the optical transmitting device 1 and the optical receiving devices 70_1 and 70_2 according to the monitoring result in the monitoring unit 81.

[0154] The controller 80 can set a subcarrier transmitter used in communication between the optical transmitting device 1 and the optical receiving device 70_1 and a subcarrier transmitter used in communication between the optical transmitting device 1 and the optical receiving device 70_2. At this time, the controller 80 can change the subcarrier transmitter used in communication with each of the optical receiving devices 70_1 and 70_2 by changing the setting of the output unit 12 included in the optical transmitting device 1.

[0155] For example, the controller 80 can change the transmission capacity between the optical transmitting device 1 and the optical receiving device 70_1 and the transmission capacity between the optical transmitting device 1 and the optical receiving device 70_2 by controlling the number of subcarrier transmitting units 11_1 to 11_m that output optical transmission signals to the transmitting ports 13_1 and 13_2.

[0156] The controller 80 can also set the wavelength band of the subcarrier used in the communication between the optical transmitting device 1 and the optical receiving device 70_1 and the wavelength band of the subcarrier used in the communication between the optical transmitting device 1 and the optical receiving device 70_2. For example, the controller 80 can set so that a subcarrier of a first wavelength band is used in the communication between the optical transmitting device 1 and the optical receiving device 70_1, and a subcarrier of a second wavelength band is used in the communication between the optical transmitting device 1 and the optical receiving device 70_2. Here, the first wavelength band and the second wavelength band are bands whose wavelengths do not overlap with each other. For example, these wavelength bands are the C band, the L band, the S band, etc. used in WDM.

[0157] The controller 80 can set up the communication between the optical transmitting device 1 and the optical receiving device 70_1 depending on at least one of the distance between the optical transmitting device 1 and the optical receiving device 70_1, the time period during which the communication is performed, and the state of the transmission path between the optical transmitting device 1 and the optical receiving device 70_1. The controller 80 can also set up the communication between the optical transmitting device 1 and the optical receiving device 70_1 using at least one of the allocation of the wavelength band of the subcarrier in the communication between the optical transmitting device 1 and the optical receiving device 70_1, the path of the optical signal, and the modulation method. The same applies to the setting up of the communication between the optical transmitting device 1 and the optical receiving device 70_2.

[0158] For example, the controller 80 may decrease the multi-level degree per subcarrier and increase the number of subcarriers as the communication distance between the optical transmitting device 1 and the optical receiving device 70_1 becomes longer. Conversely, the controller 80 may increase the multi-level degree per subcarrier and decrease the number of subcarriers as the communication distance between the optical transmitting device 1 and the optical receiving device 70_1 becomes shorter. The same applies to the modulation method in the communication between the optical transmitting device 1 and the optical receiving device 70_2.

[0159] Furthermore, when the transmission path between the optical transmitter 1 and the optical receiver 70_1 is deteriorated (when tension acts on the optical fiber, etc.), the controller 80 may, for example, reduce the multilevel degree per subcarrier. By reducing the multilevel degree per subcarrier in this way, it is possible to suppress an increase in the bit error rate. The same applies to the modulation method in the communication between the optical transmitter 1 and the optical receiver 70_2.

[0160] In the present embodiment, an optical communication system composed of one optical transmitter and two optical receivers is exemplified, but the optical communication system may include more optical transmitters and optical receivers. In this case, the controller 80 can also set the optical transmitter and optical receiver so that the entire optical communication system is in an optimal communication state.

[0161] Here, the optimal communication state can be arbitrarily determined according to the user. For example, it can be a communication state that minimizes communication costs, a communication state that maximizes communication reliability (i.e., a communication state that prioritizes uninterrupted communication and takes redundant routes into consideration), a communication state that prioritizes communication speed (a communication state that always uses the shortest route), a communication state that maximizes wavelength usage efficiency, etc.

[0162] The controller 80 can also collect information regarding changes in the network state (e.g., faults in the optical transmission path or degradation of the optical communication signal) reported by the optical transmitting device and the optical receiving device, and can reconfigure the optical transmitting device and the optical receiving device to follow the changes in the network state and to bring the entire optical communication system into an optimal communication state.

[0163] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a method for controlling the optical communication system that can perform efficient resource allocation in an optical communication network. It is also possible to provide an optical communication system and a method for controlling the optical communication system that can bring the entire optical communication system into an optimal communication state.

[0164] <Embodiment 12> Next, a twelfth embodiment of the present invention will be described. In this embodiment, a case where the optical communication system according to the present invention is applied to a centralized control network will be described. FIG. 24 is a block diagram showing an optical communication system according to this embodiment. As shown in FIG. 24, the optical communication system according to this embodiment includes a controller 80 and a plurality of nodes A to D (85_a to 85_d). The controller 80 corresponds to the controller 80 described in the eleventh embodiment. The plurality of nodes A to D (85_a to 85_d) are elements constituting a communication network. For the plurality of nodes A to D (85_a to 85_d), for example, the optical transmitting devices 1_1 to 1_6 described in the first to fourth embodiments, the optical receiving devices 2_1 to 2_6 described in the fifth to eighth embodiments, or the optical communication device 3 described in the ninth embodiment can be used.

[0165] The controller 80 monitors the communication state of each of the nodes 85_a to 85_d and controls each of the nodes 85_a to 85_d according to the communication state of each of the nodes 85_a to 85_d. The controller 80 outputs control signals 86_a to 86_d for controlling each of the nodes 85_a to 85_d to each of the nodes 85_a to 85_d.

[0166] The controller 80 can determine resource allocation (e.g., the subcarrier transmission / reception unit to be used) and optical signal paths to be used by each of the nodes 85_a to 85_d. For example, the controller 80 can change the transmission capacity between the nodes 85_a and 85_b by determining the subcarriers to be used in communication between the nodes 85_a and 85_b.

[0167] The controller 80 can also set the wavelength bands of the subcarriers used in the communication between the nodes 85_a to 85_d. For example, the controller 80 can set so that a subcarrier of a first wavelength band is used for the communication between the nodes 85_a and 85_b, and a subcarrier of a second wavelength band is used for the communication between the nodes 85_a and 85_d. Here, the first wavelength band and the second wavelength band are bands whose wavelengths do not overlap with each other. For example, these wavelength bands are the C band, L band, S band, etc. used in WDM.

[0168] The controller 80 can set up communications between the nodes 85_a to 85_d depending on at least one of the distances between the nodes 85_a to 85_d, the time periods during which communications are performed, and the state of the transmission paths between the nodes 85_a to 85_d. The time periods during which communications are performed are, for example, a predetermined time period (daytime or nighttime), a predetermined season, a time period during which a predetermined event is performed (such as backup), etc. The controller 80 can also set up communications between the nodes 85_a to 85_d using at least one of the allocation of subcarrier wavelength bands, optical signal paths, and modulation methods for communications between the nodes 85_a to 85_d.

[0169] For example, the controller 80 may decrease the multi-level per subcarrier and increase the number of subcarriers as the communication distance between the node 85_a and the node 85_b increases. Conversely, the controller 80 may increase the multi-level per subcarrier and decrease the number of subcarriers as the communication distance between the node 85_a and the node 85_b decreases. The same applies to the modulation schemes between the other nodes.

[0170] Furthermore, when the transmission path between the node 85_a and the node 85_b is deteriorated (when tension acts on the optical fiber, etc.), the controller 80 may, for example, reduce the multilevel level per subcarrier. By reducing the multilevel level per subcarrier in this way, it is possible to suppress an increase in the bit error rate. The same applies to the modulation methods between the other nodes.

[0171] In this embodiment, an optical communication system including four nodes 85_a to 85_d has been exemplified, but the optical communication system may include more than four nodes.

[0172] The controller 80 can set the optical transmitting device and the optical receiving device so that the entire optical communication system is in an optimal communication state. Here, the optimal communication state can be arbitrarily determined according to the user. For example, there is a communication state that minimizes communication costs, a communication state that maximizes communication reliability (i.e., a communication state that prioritizes uninterrupted communication and takes redundant paths into consideration), a communication state that prioritizes communication speed (a communication state that always uses the shortest path), a communication state that maximizes wavelength usage efficiency, and the like.

[0173] The controller 80 can also collect information regarding changes in the network state (e.g., faults in the optical transmission path or degradation of the optical communication signal) reported by the optical transmitting device and the optical receiving device, and can reconfigure the optical transmitting device and the optical receiving device to follow the changes in the network state and to bring the entire optical communication system into an optimal communication state.

[0174] For example, if a failure occurs in the shortest path 87_1 while data is being transmitted from node 85_a to node 85_b, the controller 80 can switch to a redundant path for transmitting data to node 85_b via path 87_2 connecting node 85_a and node 85_d, path 87_3 connecting node 85_d and node 85_c, and path 87_4 connecting node 85_c and node 85_b, so as to prevent communication from being interrupted.

[0175] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a method for controlling the optical communication system that can perform efficient resource allocation in an optical communication network. It is also possible to provide an optical communication system and a method for controlling the optical communication system that can bring the entire optical communication system into an optimal communication state.

[0176] <Embodiment 13> Next, a thirteenth embodiment of the present invention will be described. Fig. 25 is a block diagram showing an optical communication system according to this embodiment. As shown in Fig. 25, the optical communication system according to this embodiment includes an optical receiving device 2 and optical transmitting devices 75_1 and 75_2 that communicate with the optical receiving device 2. The optical receiving devices 2_1 to 2_6 described in the fifth to eighth embodiments can be used as the optical receiving device 2.

[0177] The optical receiving device 2 includes receiving ports 41_1, 41_2, a switching unit 42, and a plurality of subcarrier receiving units 43_1 to 43_m. The receiving ports 41_1, 41_2 receive multiplexed optical receiving signals 50_1, 50_2, respectively. The switching unit 42 selectively outputs each of the subcarrier receiving signals 52_1 to 52_m included in each of the optical receiving signals 51_1, 51_2 received at the receiving ports 41_1, 41_2 to the plurality of subcarrier receiving units 43_1 to 43_m. The plurality of subcarrier receiving units 43_1 to 43_m receive each of the data included in the subcarrier receiving signals 52_1 to 52_m. The configuration and operation of the optical receiving device 2 are similar to those of the optical receiving devices 2_1 to 2_6 described in the fifth to eighth embodiments, and therefore will not be described again.

[0178] The transmitting unit 77_1 of the optical transmitting device 75_1 is configured to be capable of transmitting a multiplexed optical transmission signal generated using a plurality of subcarriers. The transmitting unit 77_2 of the optical transmitting device 75_2 is configured to be capable of transmitting a multiplexed optical transmission signal generated using a plurality of subcarriers. The receiving port 41_1 is connected to the transmitting port 76_1 of the optical transmitting device 75_1 via an optical fiber, and the receiving port 41_2 is connected to the transmitting port 76_2 of the optical transmitting device 75_2 via an optical fiber. The optical receiving device 2 receives the optical receiving signal 50_1 transmitted from the optical transmitting device 75_1 via the receiving port 41_1. Also, the optical receiving device 2 receives the optical receiving signal 50_2 transmitted from the optical transmitting device 75_2 via the receiving port 41_2.

[0179] At this time, each of the subcarrier receivers 43_1 to 43_m that receives the optical reception signal via the reception port 41_1 may receive in parallel the first data (serial-parallel converted data) transmitted from the optical transmission device 75_1. Also, each of the subcarrier receivers 43_1 to 43_m that receives the optical reception signal via the reception port 41_2 may receive in parallel the second data (serial-parallel converted data) transmitted from the optical transmission device 75_2.

[0180] That is, the optical transmitting device 75_1 serial-to-parallel converts the first data to be transmitted to the optical receiving device 2, and transmits each of the serial-to-parallel converted data to the optical receiving device 2 using each optical transmission signal. The optical receiving device 2 receives a subcarrier reception signal included in the optical transmission signal (i.e., the optical reception signal 50_1) transmitted from the optical transmitting device 75_1 at a subcarrier receiving unit. Then, the data included in the subcarrier reception signal is parallel-to-serial converted to obtain the parallel-to-serial converted first data. The same applies to the second data transmitted from the optical transmitting device 75_2 to the optical receiving device 2.

[0181] In the optical communication system according to the present embodiment, the transmission capacity between the optical receiving device 2 and the optical transmitting device 75_1 corresponds to the number of subcarrier receiving units connected to the receiving port 41_1. Similarly, the transmission capacity between the optical receiving device 2 and the optical transmitting device 75_2 corresponds to the number of subcarrier receiving units connected to the receiving port 41_2. For example, when increasing the transmission capacity between the optical receiving device 2 and the optical transmitting device 75_1, the switching unit 42 is controlled to increase the number of subcarrier receiving units connected to the receiving port 41_1.

[0182] Also, a subcarrier in a first wavelength band may be used for transmission between the optical receiving device 2 and the optical transmitting device 75_1, and a subcarrier in a second wavelength band may be used for transmission between the optical receiving device 2 and the optical transmitting device 75_2. Here, the first wavelength band and the second wavelength band are bands in which the wavelengths do not overlap with each other. For example, these wavelength bands are the C band, L band, S band, etc. used in WDM.

[0183] The setting of the communication between the optical receiving device 2 and the optical transmitting device 75_1 may be determined according to at least one of the distance between the optical receiving device 2 and the optical transmitting device 75_1, the time period during which the communication is performed, and the state of the transmission path between the optical receiving device 2 and the optical transmitting device 75_1. The setting of the communication between the optical receiving device 2 and the optical transmitting device 75_1 may be determined using at least one of the allocation of the wavelength band of the subcarrier in the communication between the optical receiving device 2 and the optical transmitting device 75_1, the path of the optical signal, and the modulation method. The same applies to the setting of the communication between the optical receiving device 2 and the optical transmitting device 75_2.

[0184] For example, as the communication distance between the optical receiving device 2 and the optical transmitting device 75_1 becomes longer, the multi-level degree per subcarrier may be decreased and the number of subcarriers may be increased. Conversely, as the communication distance between the optical receiving device 2 and the optical transmitting device 75_1 becomes shorter, the multi-level degree per subcarrier may be increased and the number of subcarriers may be decreased. The same applies to the modulation method in the communication between the optical receiving device 2 and the optical transmitting device 75_2.

[0185] Also, for example, when the transmission path between the optical receiving device 2 and the optical transmitting device 75_1 is deteriorated (when tension acts on the optical fiber, etc.), for example, the multilevel degree per subcarrier may be reduced. By reducing the multilevel degree per subcarrier in this way, it is possible to suppress an increase in the bit error rate.

[0186] The communication arrangement in the optical communication system as described above may be determined by the optical receiving device 2 and the optical transmitting devices 75_1, 75_2. The optical communication system according to this embodiment may include a controller like the optical communication system described in the eleventh embodiment. In this embodiment as well, the controller may control the optical receiving device 2 and the optical transmitting devices 75_1, 75_2 according to the communication state between the optical receiving device 2 and the optical transmitting device 75_1 and the communication state between the optical receiving device 2 and the optical transmitting device 75_2.

[0187] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a method for controlling the optical communication system that can perform efficient resource allocation in an optical communication network.

[0188] <Embodiment 14> Next, a fourteenth embodiment of the present invention will be described. Fig. 26 is a block diagram showing an optical communication system according to this embodiment. As shown in Fig. 26, the optical communication system according to this embodiment includes optical transmission devices 1a and 1b and optical reception devices 2a and 2b.

[0189] The optical transmitter 1a includes a plurality of subcarrier transmitters 11a, an output unit 12a, and transmission ports 13_1a and 13_2a. The optical transmitter 1b includes a plurality of subcarrier transmitters 11b, an output unit 12b, and transmission ports 13_1b and 13_2b. The optical transmitters 1_1 to 1_6 described in the first to fourth embodiments can be used for the optical transmitters 1a and 1b. For example, the subcarrier transmitters 11a and 11b correspond to the plurality of subcarrier transmitters 11_1 to 11_m in FIG. 5, the output units 12a and 12b correspond to the output unit 12 in FIG. 5, and the transmission ports 13_1a, 13_2a, 13_1b, and 13_2b correspond to the transmission ports 13_1 and 13_2 in FIG. 5.

[0190] The optical receiver 2a includes reception ports 41_1a and 41_2a, a switching unit 42a, and a plurality of subcarrier receivers 43a. The optical receiver 2b includes reception ports 41_1b and 41_2b, a switching unit 42b, and a plurality of subcarrier receivers 43b. The optical receivers 2a and 2b can use the optical receivers 2_1 to 2_6 described in the fifth to eighth embodiments. For example, the reception ports 41_1a, 41_2a, 41_1b, and 41_2b correspond to the reception ports 41_1 and 41_2 in FIG. 15, the switching units 42a and 42b correspond to the switching unit 42 in FIG. 15, and the subcarrier receivers 43a and 43b correspond to the subcarrier receivers 43_1 to 43_m in FIG. 15.

[0191] As shown in Fig. 26, the transmission port 13_1a of the optical transmitting device 1a is connected to the reception port 41_1a of the optical receiving device 2a. The transmission port 13_2a of the optical transmitting device 1a is connected to the reception port 41_1b of the optical receiving device 2b. The transmission port 13_1b of the optical transmitting device 1b is connected to the reception port 41_2a of the optical receiving device 2a. The transmission port 13_2b of the optical transmitting device 1b is connected to the reception port 41_2b of the optical receiving device 2b.

[0192] At this time, the optical transmitter 1a transmits data to the optical receiver 2a using an optical transmission signal 23_1a generated using a plurality of subcarriers in a first wavelength band. The optical transmitter 1a also transmits data to the optical receiver 2b using an optical transmission signal 23_2a generated using a plurality of subcarriers in a second wavelength band. The optical transmitter 1b also transmits data to the optical receiver 2a using an optical transmission signal 23_1b generated using a plurality of subcarriers in the second wavelength band. The optical transmitter 1b also transmits data to the optical receiver 2b using an optical transmission signal 23_2b generated using a plurality of subcarriers in the first wavelength band. Here, the first wavelength band and the second wavelength band are bands whose wavelengths do not overlap with each other. For example, these wavelength bands are the C band, the L band, the S band, etc. used in WDM.

[0193] By combining the wavelength bands of the optical transmission signals 23_1a, 23_2a, 23_1b, and 23_2b used in the communication between the optical transmitting devices 1a, 1b and the optical receiving devices 2a, 2b as described above, it is possible to prevent overlapping of the wavelength bands of the subcarriers used in the communication between the optical transmitting devices 1a, 1b and the optical receiving devices 2a, 2b.

[0194] In the optical communication system according to the present embodiment, the settings of the communication between the optical transmitters 1a, 1b and the optical receivers 2a, 2b may be determined according to at least one of the distance between the optical transmitters 1a, 1b and the optical receivers 2a, 2b, the time period during which the communication is performed, and the state of the transmission path between the optical transmitters 1a, 1b and the optical receivers 2a, 2b. The settings of the communication between the optical transmitters 1a, 1b and the optical receivers 2a, 2b may be determined using at least one of the allocation of the wavelength band of the subcarrier in the communication between the optical transmitters 1a, 1b and the optical receivers 2a, 2b, the path of the optical signal, and the modulation method.

[0195] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a control method for the optical communication system that can perform efficient resource allocation in an optical communication network.

[0196] <Embodiment 15> Next, a fifteenth embodiment of the present invention will be described. Fig. 27 is a block diagram showing an optical communication system according to this embodiment. As shown in Fig. 27, the optical communication system according to this embodiment includes optical communication devices 3a to 3d. Here, the optical communication devices 3a to 3d are optical communication devices capable of transmitting and receiving.

[0197] The optical communication device 3a includes a subcarrier transceiver 91a, an optical transmission / reception signal switch 92a, and transmission / reception ports 93_1a and 93_2a. The optical communication device 3b includes a subcarrier transceiver 91b, an optical transmission / reception signal switch 92b, and transmission / reception ports 93_1b and 93_2b. The optical communication device 3c includes a subcarrier transceiver 91c, an optical transmission / reception signal switch 92c, and transmission / reception ports 93_1c and 93_2c. The optical communication device 3d includes a subcarrier transceiver 91d, an optical transmission / reception signal switch 92d, and transmission / reception ports 93_1d and 93_2d. The optical communication device 3 described in the ninth embodiment (see FIG. 20) can be used for the optical communication devices 3a to 3d. For more detailed configurations, see FIG. 5 (second embodiment) and FIG. 15 (sixth embodiment).

[0198] Here, the subcarrier transmitting / receiving unit 91a of the optical communication device 3a includes the subcarrier transmitting units 11_1-11_m of Fig. 5 and the subcarrier receiving units 43_1-43_m of Fig. 15, the optical transmitting / receiving signal switching unit 92a includes the output unit 12 of Fig. 5 and the switching unit 42 of Fig. 15, and the transmitting / receiving ports 93_1a, 93_2a correspond to the transmitting ports 13_1, 13_2 of Fig. 5 and the receiving ports 41_1, 41_2 of Fig. 15. The same applies to the other optical communication devices 3b-3d.

[0199] 27, the transmission / reception port 93_1a of the optical communication device 3a is connected to the transmission / reception port 93_1c of the optical communication device 3c. The transmission / reception port 93_2a of the optical communication device 3a is connected to the transmission / reception port 93_1d of the optical communication device 3d. The transmission / reception port 93_1b of the optical communication device 3b is connected to the transmission / reception port 93_2c of the optical communication device 3c. The transmission / reception port 93_2b of the optical communication device 3b is connected to the transmission / reception port 93_2d of the optical communication device 3d.

[0200] At this time, the optical communication device 3a and the optical communication device 3c communicate using an optical signal 25_1 generated using a plurality of subcarriers in a first wavelength band. Also, the optical communication device 3a and the optical communication device 3d communicate using an optical signal 25_2 generated using a plurality of subcarriers in a second wavelength band. Also, the optical communication device 3b and the optical communication device 3c communicate using an optical signal 25_3 generated using a plurality of subcarriers in a second wavelength band. Also, the optical communication device 3b and the optical communication device 3d communicate using an optical signal 25_4 generated using a plurality of subcarriers in a first wavelength band. Here, the first wavelength band and the second wavelength band are bands whose wavelengths do not overlap with each other. For example, these wavelength bands are the C band, the L band, the S band, etc. used in WDM.

[0201] By combining the wavelength bands of the optical signals 25_1 to 25_4 used in the communications between the optical communication devices 3a to 3d as described above, it is possible to prevent the wavelength bands of the subcarriers used in the communications between the optical communication devices 3a to 3d from overlapping with each other.

[0202] In the optical communication system according to the present embodiment, the settings of the communication between the optical communication devices 3a to 3d may be determined according to at least one of the distance between the optical communication devices 3a, 3b and the optical communication devices 3c, 3d, the time period during which the communication is performed, and the state of the transmission path between the optical communication devices 3a, 3b and the optical communication devices 3c, 3d. The settings of the communication between the optical communication devices 3a, 3b and the optical communication devices 3c, 3d may be determined using at least one of the allocation of the wavelength band of the subcarrier in the communication between the optical communication devices 3a, 3b and the optical communication devices 3c, 3d, the path of the optical signal, and the modulation method.

[0203] According to the invention of the present embodiment described above, it is possible to provide an optical communication system and a control method for the optical communication system that can perform efficient resource allocation in an optical communication network.

[0204] In the above embodiment, the present invention has been described as a hardware configuration, but the present invention is not limited to this. Any process of the present invention can be realized by causing a CPU (Central Processing Unit) to execute a computer program.

[0205] The program can be stored and provided to the computer using various types of non-transitory computer readable media. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R / W, and semiconductor memory (e.g., mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). The program may also be provided to the computer by various types of transitory computer readable media. Examples of the transitory computer readable media include electric signals, optical signals, and electromagnetic waves. The transitory computer readable media can provide the program to the computer via a wired communication path such as an electric wire and an optical fiber, or via a wireless communication path.

[0206] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention. [Explanation of symbols]

[0207] 1, 1_1~1_6 Optical transmitter 2, 2_1~2_6 Optical receiving device 3. Optical communication devices 11, 11_1~11_m Subcarrier transmitter 12 Optical transmission signal switching section 13 Outbound Ports 14 Light source 15 Subcarrier generation unit 16 Signal conversion section 21_1~21_m Optical transmission signal 22_1, 22_2 Optical transmission signal 23_1, 23_2 Optical transmission signal 26_1 First Route 26_2 Second Route 30 Switching section 31_1, 31_2 Optical multiplexer 32 Optical multiplexer 33 Optical demultiplexer 41_1, 41_2 receiving ports 42 Switching section 43_1~43_m Subcarrier receiver 44_1, 44_2 Local oscillator 45 Signal Processing Section 51_1, 51_2 Optical receiving signal 52_1~52_m Subcarrier received signal 53_1~53_6 Received signal 60_1, 60_2 Optical splitter 61 Optical Switch 62 Optical multiplexer 63 Optical demultiplexer 64 multiplexed optical signals 80 Controller 81 Monitoring Department 82 Setting section

Claims

1. a plurality of transceivers for respectively transmitting and receiving a plurality of optical signals corresponding to a plurality of subcarriers included in one channel; an input / output unit that inputs and outputs the plurality of optical signals via a first path connected to a first optical communication device or a second path connected to a second optical communication device; a switching unit that dynamically switches a transmission capacity between the first optical communication device and the second optical communication device; A signal processing unit that sets compensation parameters for compensating for the effect of mutual interference between subcarrier reception signals, the switching unit switches input / output destinations of some optical signals among a plurality of optical signals input / output via the first path to the second path when increasing a transmission capacity between the second optical communication device and the first optical communication device. Optical communication equipment.

2. The switching unit switches an input / output destination of an optical signal of an unused subcarrier among the plurality of optical signals.

2. The optical communication device according to claim 1.

3. the switching unit determines the number of subcarriers to be used in the first path in accordance with a transmission capacity between the first optical communication device and the first optical communication device.

3. The optical communication device according to claim 2.

4. The switching unit switches an input / output destination of an optical signal from an unused transceiver unit among the plurality of transceivers.

2. The optical communication device according to claim 1.

5. the switching unit determines the number of optical signals of the transmitting / receiving unit to be used in the first path in accordance with a transmission capacity between the first optical communication device and the first optical communication device.

5. The optical communication device according to claim 4.

6. the input / output unit includes a first transmission / reception port connected to a first optical communication device and a second transmission / reception port connected to a second optical communication device; The switching unit switches connections between the plurality of transmitting / receiving units and the first and second transmitting / receiving ports.

6. An optical communication device according to claim 1.

7. when a transmission capacity between the first optical communication device and the plurality of transceivers is changed in a state in which the plurality of transceivers are connected to the first transceiver port, the switching unit switches the connection of some of the plurality of transceivers to the second transceiver port.

7. The optical communication device according to claim 6.

8. A first optical communication device, a second optical communication device and a third optical communication device are provided. The first optical communication device is a plurality of transceivers for respectively transmitting and receiving a plurality of optical signals corresponding to a plurality of subcarriers included in one channel; an input / output unit that inputs and outputs the plurality of optical signals via a first path connected to the second optical communication device or a second path connected to the third optical communication device; a switching unit that dynamically switches between a transmission capacity between the first optical communication device and the second optical communication device and a transmission capacity between the first optical communication device and the third optical communication device; A signal processing unit that sets compensation parameters for compensating for the effect of mutual interference between subcarrier reception signals, the switching unit switches, when increasing a transmission capacity between the first optical communication device and the third optical communication device, a destination of some of the optical signals input / output via the first path to the second path. Optical communication system.

9. Transmitting and receiving a plurality of optical signals corresponding to a plurality of subcarriers included in one channel, inputting and outputting the plurality of optical signals via a first path connected to a first optical communication device or a second path connected to a second optical communication device; Setting compensation parameters for compensating for the effect of mutual interference between the subcarrier received signals; when increasing a transmission capacity between the second optical communication device and the first optical communication device, a destination of some of the optical signals input / output via the first path is switched to the second path; Optical communication method.

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