Optical transceiver, optical communication system, and method and program relating to the optical transceiver

Abstract

To provide an optical transceiver which autonomously sets a channel of an optical signal to be transmitted / received optically, an optical communication system, an optical transmission device, a channel setting method for the optical transceiver and a program.SOLUTION: In an optical transceiver 100, a wavelength variable optical transmission section 10 transmits an optical signal for first channel setting including first channel information, and a wavelength variable optical reception section 20 transfers second channel information included in an optical signal for second channel setting which is received from the other optical transceiver. In the optical transceiver, in channel setting processing which is autonomously executed in a case where the optical transceiver is mounted to an optical transmission device, the wavelength variable optical transmission section transmits the optical signal for the first channel setting, the wavelength variable optical reception section transfers the second channel information upon receiving the optical signal for second channel setting and on the basis of the transferred second channel information, a control section sets a first channel, which is indicated in the second channel information, as a channel of an optical signal to be received by the wavelength variable optical reception section.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an optical transceiver, an optical communication system, an optical transmission device, and a channel setting method and program for an optical transceiver. [Background technology]

[0002] Optical communication systems that enable optical communication by connecting terrestrial base stations via optical cables are widely used. Each base station is equipped with optical transmission equipment equipped with one or more optical transceivers. When an optical transceiver is first used, it must be initialized.

[0003] A technology has been disclosed in which the transmission rate, data format, and transmission format are adjusted between optical transceivers before data communication begins (Patent Document 1). In this technology, test signals with the transmission rate and transmission format set between the optical transceivers are transmitted and received between the optical transceivers. The transmission rate is set by comparing the transmission rate used to transmit the test signal with the transmission rate of the received test signal. The transmission format is set corresponding to the transmission path state estimated in response to error detection in the test signal. After the transmission rate and transmission format are determined, the data format is determined by transmitting and receiving information related to the data format. After these are determined, communication between the optical transceivers begins.

[0004] A method for initiating bidirectional data packet communication between optical transceivers that are not yet communicating has also been proposed (Patent Document 2). In this method, prior to the bidirectional data packet communication, a connection packet containing identification information for each optical transceiver and transmitted at a speed lower than the transmission speed of the data packet is sent and received between the optical transceivers via an optical fiber transmission line. Then, based on the identification information in the connection packet received by each optical transceiver, one optical transceiver is designated as the master and the other as the slave. The master optical transceiver then notifies the slave optical transceiver of the transmission method set by this notification using a configuration packet. Bidirectional communication between the optical transceivers is then performed using the transmission method set by this notification.

[0005] Furthermore, a method for negotiating wavelengths used for communication between optical modules in a PON (Passive Optical Network) system consisting of an OLT (Optical Line Terminal) and an ONU (Optical Network Unit) has been proposed (Patent Document 3). In this method, an optical module (referred to as a first optical module) periodically transmits a wavelength idle signal of a selected first wavelength to a counterpart optical module (referred to as a second optical module). This wavelength idle signal indicates that the selected first wavelength is available for use, and the second optical module, upon receiving the wavelength idle signal, transmits a wavelength request message of a second wavelength corresponding to the first wavelength to the first optical module. Upon receiving the wavelength request message, the first optical module transmits a wavelength grant message to the second optical module to grant use of the selected wavelength. This determines the wavelengths used for transmitting and receiving optical signals between the two optical modules. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-229298 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-229299 [Patent Document 3] Special Publication No. 2017-539142 Summary of the Invention [Problem to be solved by the invention]

[0007] Optical transmission equipment generally includes multiple optical transceivers, and requires initial configuration to set the channels (wavelengths) used by each optical transceiver for transmission and reception. Manually configuring the channels for the numerous optical transceivers installed in the optical transmission equipment requires a significant amount of time. Therefore, from the perspective of reducing the time required for configuration, it is desirable to be able to autonomously configure the channels of optical signals that the optical transceivers will transmit and receive as an initial configuration when they are installed in the optical transmission equipment.

[0008] In the method of Patent Document 3, the channel (wavelength) to be used for transmission and reception can be set by wavelength negotiation between two optical modules (optical transceivers), but this is premised on the fact that optical signals of a specific channel can be transmitted and received between the two optical modules in the first place. In other words, the first and second wavelengths to be used must be assigned manually. In other words, the method of Patent Document 3 simply uses the assigned channel to confirm that the transmission and reception path is available, but it cannot autonomously set the channel to be used.

[0009] The present invention has been made in view of the above circumstances, and has as its object to autonomously set a channel for an optical signal transmitted and received by an optical transceiver. [Means for solving the problem]

[0010] An optical transceiver according to one aspect of the present invention is an optical transceiver that can be attached to an optical transmission device, and includes: a wavelength-tunable optical transmitter configured to be able to transmit a first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; a wavelength-tunable optical receiver configured to, when receiving a second channel setting optical signal from another optical transceiver, transfer second channel information that indicates a channel of the second channel setting optical signal and that is included in the second channel setting optical signal; and a control unit that controls the wavelength-tunable optical transmitter and the wavelength-tunable optical receiver, When the optical transceiver is attached to the optical transmission device, the optical transceiver autonomously executes a channel setting process, and in the channel setting process, the wavelength-tunable optical transmitting unit transmits the first channel setting optical signal, the wavelength-tunable optical receiving unit transfers the second channel information when it receives the second channel setting optical signal, and the control unit sets the first channel indicated by the second channel information as the channel of the optical signal received by the wavelength-tunable optical receiving unit based on the second channel information transferred by the wavelength-tunable optical receiving unit.

[0011] An optical communication system according to one aspect of the present invention includes a first optical transmission device having a plurality of optical transceivers including a first optical transceiver and a first optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels; a second optical transmission device having a plurality of optical transceivers including a second optical transceiver and a second optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels; and an optical cable connecting the first optical transmission device and the second optical transmission device, wherein the first optical transceiver has a wavelength-tunable optical transmission unit configured to be able to transmit the first channel setting optical signal including first channel information indicating the channel of the first channel setting optical signal; and and a control unit for controlling the wavelength-tunable optical transmitting unit and the wavelength-tunable optical receiving unit, wherein the first optical transceiver autonomously executes a channel setting process when the first optical transceiver is attached to the first optical transmission device and the second optical transceiver is attached to the second optical transmission device, and in the channel setting process, the wavelength-tunable optical transmitting unit transmits the first channel setting optical signal, and the wavelength-tunable optical receiving unit transfers the second channel information when it receives the second channel setting optical signal, and the control unit sets the first channel indicated by the second channel information as the channel of the optical signal received by the wavelength-tunable optical receiving unit based on the second channel information transferred by the wavelength-tunable optical receiving unit.

[0012] An optical transmission device according to one aspect of the present invention comprises a plurality of optical transceivers that can be attached to the optical transmission device, and an optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels, wherein each of the plurality of optical transceivers comprises a wavelength-tunable optical transmitter configured to be able to transmit the first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal, and a wavelength-tunable optical transmitter configured to, when receiving a second channel setting optical signal from another optical transceiver provided in another optical transmission device, forward second channel information indicating the channel of the second channel setting optical signal, the second channel information being included in the second channel setting optical signal. and a control unit that controls the tunable optical transmitter and the tunable optical receiver, wherein each of the optical transceivers autonomously executes a channel setting process when the optical transceiver is attached to the optical transmission device, and in the channel setting process, the tunable optical transmitter transmits the first channel setting optical signal, and the tunable optical receiver transfers the second channel information when it receives the second channel setting optical signal, and the control unit sets the first channel indicated by the second channel information as the channel of the optical signal received by the tunable optical receiver based on the second channel information transferred by the tunable optical receiver.

[0013] A channel setting method for an optical transceiver according to one aspect of the present invention is a channel setting method using an optical transceiver that can be attached to an optical transmission device, in which, when the optical transceiver is attached to the optical transmission device, the optical transceiver autonomously transmits a first channel setting optical signal including first channel information indicating the channel of the first channel setting optical signal, and, when the optical transceiver receives a second channel setting optical signal from another optical transceiver, transfers second channel information that is included in the second channel setting optical signal and indicates the channel of the second channel setting optical signal, and sets the first channel indicated by the second channel information as the channel of the optical signal to be received based on the transferred second channel information.

[0014] A program according to one aspect of the present invention is an optical transceiver that can be attached to an optical transmission device, the program having a control unit configured as an arithmetic unit capable of controlling a wavelength-tunable optical transmitting unit and a wavelength-tunable optical receiving unit, and that causes the control unit to execute the following operations when the optical transceiver is attached to the optical transmission device: autonomously transmitting from the wavelength-tunable optical transmitting unit a first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; when receiving a second channel setting optical signal from another optical transceiver, transferring by the wavelength-tunable optical receiving unit second channel information that is included in the second channel setting optical signal and indicates the channel of the second channel setting optical signal; and, based on the second channel information transferred by the wavelength-tunable optical receiving unit, setting the first channel indicated by the second channel information as the channel of the optical signal received by the wavelength-tunable optical receiving unit. [Effects of the Invention]

[0015] According to the present invention, an optical transceiver can autonomously set a channel for transmitting and receiving optical signals. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating a basic configuration of an optical communication system according to a first embodiment. [Figure 2] 1 is a diagram illustrating a configuration of an optical transmission device according to a first embodiment and an example of transmission and reception of an optical signal; [Figure 3] FIG. 2 is a diagram illustrating a configuration of a channel setting optical signal. [Figure 4] FIG. 1 is a diagram illustrating a basic configuration of an optical transceiver according to a first embodiment. [Figure 5] FIG. 2 is a diagram illustrating a more detailed configuration of the optical transceiver according to the first embodiment. [Figure 6] FIG. 2 illustrates transmission of a channel setting optical signal in the optical transceiver according to the first embodiment. [Figure 7]FIG. 2 illustrates reception of a channel setting optical signal in the optical transceiver according to the first embodiment. [Figure 8] 10A and 10B are diagrams illustrating an example of a channel setting optical signal transmitted and received between two optical transceivers in a channel setting process. [Figure 9] FIG. 10 is a diagram showing state transitions in a channel setting process. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same elements are designated by the same reference numerals, and redundant explanations will be omitted as necessary.

[0018] Embodiment 1 An optical communication system 1000 according to a first embodiment will be described. FIG. 1 schematically illustrates a basic configuration of the optical communication system 1000 according to the first embodiment. In the optical communication system 1000, optical transmission devices 1 and 2 are provided in land terminal stations BS1 and BS2, respectively. The optical transmission devices 1 and 2 are connected by optical cables C1 and C2. The optical cables C1 and C2 may be laid on land or under the sea. In this example, the optical cable C1 is used as a cable for transmitting an optical signal transmitted from the optical transmission device 1 to the optical transmission device 2. The optical cable C2 is used as a cable for transmitting an optical signal transmitted from the optical transmission device 2 to the optical transmission device 1. Note that one or more optical amplifiers AMP may be inserted into the optical cables C1 and C2 to compensate for optical signals attenuated during transmission.

[0019] 1 shows a simplified configuration of the optical communication system for the sake of simplicity, and for example, one optical transmission device may be communicably connected to two or more optical transmission devices via an optical cable. Furthermore, an optical add / drop device that adds / drops optical signals may be inserted into the optical cable as needed to branch off branch paths from the trunk path. However, this is merely an example, and it goes without saying that the optical communication system may be configured to have any path (trunk path and branch path) that enables optical communication between any number of optical transmission devices.

[0020] The configuration of an optical transmission device will be explained below. The optical transmission device has multiple optical transceivers, an optical multiplexer that multiplexes optical signals to be transmitted and outputs a multiplexed optical signal, and an optical demultiplexer that demultiplexes the received multiplexed optical signal to each optical transceiver. For simplicity, the optical multiplexer and optical demultiplexer will be combined and treated as a single optical multiplexer / demultiplexer below.

[0021] 2 schematically illustrates an example of the configuration of optical transmission devices 1 and 2 according to the first embodiment and the transmission and reception of optical signals. The optical transmission device 1 includes a plurality of optical transceivers and an optical multiplexer / demultiplexer M1 (also referred to as a second optical multiplexer / demultiplexer). In this example, the optical transmission device 1 includes 25 optical transceivers A1 to A25. Two different channels are assigned to each of the optical transceivers A1 to A25.

[0022] The number of ports of the optical multiplexer / demultiplexer M1 connected to the optical transceivers is equal to the number of channels. The transmit port of optical transceiver Ai (i is an integer between 1 and 25) is connected to the port for channel CH(2i-1) of the optical multiplexer / demultiplexer M1, and the receive port is connected to the port for channel CH(2i). In other words, the optical transceiver Ai is assigned the transmit channel CH(2i-1) and the receive channel CH(2i). That is, the optical transceivers A1, A2, A3, ..., A25 are assigned the channels CH1 and CH2, CH3 and CH4, CH5 and CH6, ..., CH49 and CH50. In this way, a specific channel is assigned to each of the two ports of the optical transceiver, with no overlap within the optical transmission device.

[0023] The optical transmission device 2 has the same configuration as the optical transmission device 1. That is, the optical transmission device 2 has 25 optical transceivers B1 to B25 and an optical multiplexer / demultiplexer M2 (also referred to as a first optical multiplexer / demultiplexer).

[0024] The number of ports of the optical multiplexer / demultiplexer M2 connected to the optical transceivers is equal to the number of channels. The receiving port of the optical transceiver Bi is connected to the port for channel CH(2i-1) of the optical multiplexer / demultiplexer M2, and the transmitting port is connected to the port for channel CH(2i). In other words, the optical transceiver Bi is assigned a transmitting channel CH(2i) and a receiving channel CH(2i-1). That is, the optical transceivers B1, B2, B3, ..., B25 are assigned channels CH1 and CH2, CH3 and CH4, CH5 and CH6, ..., CH49 and CH50. In this way, a specific channel is assigned to each of the two ports of the optical transceiver, with no overlap within the optical transmission device.

[0025] With the above configuration, two common channels are assigned to the optical transceiver Ai and the optical transceiver Bi, and optical signals can be transmitted and received using these two channels.

[0026] This example shows the transmission and reception paths of optical signals, focusing on optical transceiver A2 in optical transmission device 1 and optical transceiver B2 in optical transmission device 2. Optical transceiver A2 transmits an optical signal using channel CH3, and the transmitted optical signal on channel CH3 is received by optical transceiver B2. Optical transceiver B2 also transmits an optical signal using channel CH4, and the transmitted optical signal on channel CH4 is received by optical transceiver A2.

[0027] In FIG. 2, for the sake of simplicity, attention is focused on optical transceiver A2 and optical transceiver B2, and it goes without saying that other optical transceivers can also transmit and receive optical signals using two channels in the same manner.

[0028] In this way, to transmit and receive optical signals on a specific channel, the channel to be used must be set in the optical transceiver on the transmitting side and the optical transceiver on the receiving side. Generally, the channel setting in the optical transceiver is performed as part of the initial setup procedure when the optical transceiver is installed in the optical transmission device.

[0029] However, for example, in the case of the optical communication system described above, which uses a maximum of 50 channels, two optical transmission devices require a total of 50 optical transceivers, each with two channels, for a total of 100 configuration operations. However, performing this configuration manually poses a problem in that it requires an enormous amount of time. Furthermore, since multiple configuration operations must be performed without error, manual configuration operations can be considered problematic from the standpoint of reliability.

[0030] In this embodiment, in order to address this problem, an optical transceiver that autonomously performs channel setting processing when attached to an optical transmission device will be described.

[0031] For example, when optical transceivers A2 and B2 are installed in an optical transmission device, the optical transceivers A2 and B2 autonomously execute channel setup processing, transmitting and receiving channel setup optical signals between the optical transceivers A2 and B2.

[0032] FIG. 3 shows a schematic diagram of the configuration of a channel setting optical signal. The channel setting optical signal S includes at least local channel information L and remote channel information R stored in the optical transceiver. The local channel information L indicates the channel of the channel setting optical signal S transmitted by the optical transceiver when the optical transceiver transmits the channel setting optical signal S during the channel setting process. The remote channel information R indicates the channel of the channel setting optical signal S received by the optical transceiver when the optical transceiver receives the channel setting optical signal S during the channel setting process. The channel setting optical signal S may include other information as necessary. FIG. 3 shows an example in which the channel setting optical signal S includes header information OH.

[0033] The configuration of the optical transceiver according to the present embodiment will now be described. Fig. 4 schematically shows the basic configuration of the optical transceiver according to the first embodiment. Fig. 5 shows the configuration of the optical transceiver according to the first embodiment in more detail. Note that since the optical transceivers A1 to A25 and B1 to B25 have similar configurations, the optical transceiver 100, which has the same structure as these transceivers, will be described as a representative example.

[0034] The optical transceiver 100 includes a wavelength-tunable optical transmitter 10, a wavelength-tunable optical receiver 20, and a controller 30. The controller 30 controls the operation of the wavelength-tunable optical transmitter 10 and the wavelength-tunable optical receiver 20 in response to, for example, a command signal INS provided from an optical transmission device in which the optical transceiver 100 is implemented.

[0035] The wavelength-tunable optical transmitter 10 is configured to be able to change the wavelength of the optical signal to be transmitted, i.e., the channel. The wavelength-tunable optical transmitter 10 has a driver 11 and an optical signal transmitter 12. The driver 11 outputs a drive signal DRV to the optical signal transmitter 12 based on a received main signal (data signal) IN. The wavelength-tunable optical signal transmitter 12 is configured as, for example, a TOSA (Transmitter Optical Sub-Assembly), and is configured to be able to output an optical signal LS1 modulated in accordance with the drive signal DRV.

[0036] The tunable optical receiving unit 20 is configured to be able to change the wavelength of the received optical signal, i.e., the channel. The tunable optical receiving unit 20 includes an amplifier 21 and an optical signal receiving unit 22. The tunable optical signal receiving unit 22 is configured, for example, as a ROSA (Receiver Optical Sub-Assembly) and converts the received optical signal LS2 into an output signal DAT, which is an electrical signal, and outputs it to the amplifier 21. The amplifier 21 is configured, for example, as a limiting amplifier and amplifies the output signal DAT to a predetermined amplitude and outputs the amplified output signal OUT to an external device of the optical transceiver 100, for example, an optical transmission device in which the optical transceiver 100 is implemented.

[0037] Next, transmission of a channel setting optical signal in the optical transceiver 100 will be described. FIG. 6 illustrates transmission of the channel setting optical signal SA in the optical transceiver 100. The control unit 30 provides a control signal CON to the driver 11, thereby superimposing a low-speed (low-frequency) signal on the drive signal DRV output by the driver 11. For example, by connecting the serial port of the control unit 30 to the output amplitude disable terminal of the driver 11 and outputting the control signal CON to the output amplitude disable terminal, the drive signal DRV can be on / off modulated, i.e., the amplitude can be set to 0 or 1. The optical signal transmitter 12 can output an on / off modulated channel setting optical signal SA in response to the drive signal DRV that has been slow-modulated to transmit the channel setting optical signal SA. At this time, by including local channel information L and remote channel information R in the control signal CON, the channel setting optical signal SA output by the optical signal transmitter 12 will include the local channel information L and the remote channel information R.

[0038] Next, the reception of a channel setting optical signal in the optical transceiver 100 will be described. FIG. 7 shows the reception of the channel setting optical signal SB in the optical transceiver 100. When the optical signal receiver 22 receives the channel setting optical signal SB generated as described above, the amplitude of the output signal DAT fluctuates depending on the amplitude of the on / off modulated channel setting optical signal SB. The amplifier 21 detects the amplitude of the output signal DAT and outputs a detection signal DET indicating the detection result to the controller 30. This allows the controller 30 to receive local channel information L and remote channel information R regardless of the channel of the channel setting optical signal SB simply by monitoring the amplitude of the channel setting optical signal SB.

[0039] Next, we will explain the channel setting process of the optical transceivers using the above-mentioned channel setting optical signals. Optical transceivers A2 and B2 change the local channel information L, i.e., by transmitting channel setting optical signals while sweeping the local channels, to determine the channels to be used for transmitting and receiving optical signals between them, following the procedure shown below. Figure 8 shows an example of the channel setting optical signals transmitted and received between optical transceivers A2 and B2 during the channel setting process. Figure 9 shows the state transitions during the channel setting process.

[0040] At the start of the channel setting process, the optical transceivers A2 and B2 are in an unknown state (hereinafter referred to as state EU: Each channel Unknown) in which the transmit and receive channels to be set are unknown. In other words, neither the optical transceiver that will be the transmission partner nor the optical transceiver that will transmit the received optical signal have been identified.

[0041] Thereafter, the optical transceivers A2 and B2 repeatedly transmit the channel setting optical signals while sweeping the local channels, starting from channel CH1 and proceeding in ascending order.

[0042] In the following, the optical transceiver B2 will also be referred to as the first optical transceiver, and the optical transceiver A2 will also be referred to as the second optical transceiver. The channel setting optical signal output by the optical transceiver B2 will also be referred to as the first channel setting optical signal. The channel setting optical signal output by the optical transceiver A2 will also be referred to as the second channel setting optical signal.

[0043] Channel CH3 is also referred to as the first channel, and channel CH4 is also referred to as the second channel.

[0044] The local channel information LB of the optical transceiver B2 is also referred to as the first channel information, and the local channel information LA of the optical transceiver A2 is also referred to as the second channel information. The remote channel information RB of the optical transceiver B2 is also referred to as the third channel information, and the local channel information LA of the optical transceiver A2 is also referred to as the second channel information.

[0045] (1) SA1 / LA:CH1, RA:NONE In the example of Figure 8, optical transceiver A2 first transmits a channel setting optical signal SA1 for channel CH1, with local channel information LA set to channel CH1 and remote channel information RA set to null (NONE). In this example, channel CH1 is the channel used for transmission from optical transceiver A1 to optical transceiver B1. That is, the port for channel CH1 of optical multiplexer / demultiplexer M2 of optical transmission device 2 is connected to the receiving port of optical transceiver B1. Therefore, the channel setting optical signal SA1 is blocked by optical multiplexer / demultiplexer M2 and does not reach optical transceiver B2.

[0046] (2)SB1 / LB:CH1,RB:NONE Next, optical transceiver B2 transmits a channel setting optical signal SB1 for channel CH1, with local channel information LB set to channel CH1 and remote channel information RB set to null (NONE). Because the transmit port of optical transceiver A1 is connected to the port for channel CH1 of optical multiplexer / demultiplexer M1 in optical transmission device 1, the channel setting optical signal SB1 is blocked by optical multiplexer / demultiplexer M1 and does not reach optical transceiver A2.

[0047] (3) SA2 / LA:CH2, RA:NONE Next, optical transceiver A2 transmits a channel setting optical signal SA2 for channel CH2, with local channel information LA set to channel CH2 and remote channel information RA set to null (NONE). In this example, channel CH2 is the channel used for transmission from optical transceiver B1 to optical transceiver A1. That is, the port for channel CH2 of optical multiplexer / demultiplexer M2 of optical transmission device 2 is connected to the transmit port of optical transceiver B1. Therefore, the channel setting optical signal SA2 is blocked by optical multiplexer / demultiplexer M2 and does not reach optical transceiver B2.

[0048] (4) SB2 / LA:CH2,RA:NONE Next, optical transceiver B2 transmits a channel setting optical signal SB2 for channel CH2, with local channel information LB set to channel CH2 and remote channel information RB set to null (NONE). Because the receiving port of optical transceiver A1 is connected to the port for channel CH2 of optical multiplexer / demultiplexer M1 in optical transmission device 1, the channel setting optical signal SB2 is blocked by optical multiplexer / demultiplexer M1 and does not reach optical transceiver A2.

[0049] (5)SA3 / LA:CH3,RA:NONE, state transition: EU→PK Next, the optical transceiver A2 transmits a channel setting optical signal SA3 for channel CH3, with local channel information L set to channel CH3 and remote channel information R set to null (NONE). In this example, channel CH3 is the channel used for transmission from the optical transceiver A2 to the optical transceiver B2. That is, the port for channel CH3 of the optical multiplexer / demultiplexer M2 of the optical transmission device 2 is connected to the receiving port of the optical transceiver B2. Therefore, the channel setting optical signal SA3 for channel CH3 is received by the optical transceiver B2 via the optical multiplexer / demultiplexer M2.

[0050] This allows the optical transceiver B2 to receive channel CH3 as the local channel information LA of the optical transceiver A2. Since the local channel information LA of the optical transceiver A2 is remote channel information RB for the optical transceiver B2, the optical transceiver B2 fixes the remote channel information RB to channel CH3.

[0051] At this time, the optical transceiver B2 enters a state in which it has detected the transmission channel of the partner optical transceiver A (state PK: Partner CH Known), and the state transitions from EU to PK.

[0052] (6)SB4 / LB:CH3,RB:NONE Next, optical transceiver B2 transmits a channel setting optical signal SB3 for channel CH3, whose local channel information LB is for channel CH3 and whose remote channel information RB is for channel CH3. Because the transmit port of optical transceiver A2 is connected to the port for channel CH3 of optical multiplexer / demultiplexer M1 in optical transmission device 1, the channel setting optical signal SB3 for channel CH3 is blocked by optical multiplexer / demultiplexer M1 and does not reach optical transceiver A2.

[0053] (7) SA4 / LA:CH4, RA:NONE Next, optical transceiver A2 transmits a channel setting optical signal SA4 for channel CH4, with local channel information LA set to channel CH4 and remote channel information RA set to null (NONE). In this example, channel CH4 is the channel used for transmission from optical transceiver B2 to optical transceiver A2. That is, the port for channel CH4 of optical multiplexer / demultiplexer M2 of optical transmission device 2 is connected to the transmit port of optical transceiver B2. Therefore, the channel setting optical signal SA4 for channel CH4 is blocked by optical multiplexer / demultiplexer M2 and does not reach optical transceiver B2.

[0054] (8) SB4 / LB: CH4, RA: CH3, state transition: EU → EK Next, optical transceiver B2 transmits a channel setting optical signal SB4 for channel CH4, with local channel information LB set to channel CH4 and remote channel information RB set to channel CH3. The receiving port of optical transceiver B2 is connected to the port for channel CH4 of optical multiplexer / demultiplexer M1 of optical transmission device 1. Therefore, the channel setting optical signal SB4 for channel CH4 is received by optical transceiver A2 via optical multiplexer / demultiplexer M1.

[0055] This allows the optical transceiver A2 to receive channel CH4 as the local channel information LB of the optical transceiver B2. Since the local channel information LB of the optical transceiver B2 is the remote channel information RA for the optical transceiver A2, the optical transceiver A2 fixes the remote channel information RA to channel CH4.

[0056] Furthermore, the optical transceiver A2 can receive channel CH3 as the remote channel information RB of the optical transceiver B2. Since the remote channel information RB of the optical transceiver B2 is local channel information LA for the optical transceiver A2, the optical transceiver A2 fixes the local channel information LA to channel CH3. Note that fixing the local channel information LA to channel CH3 sets the transmission channel for the optical transceiver A2, so the optical transceiver A2 stops channel sweeping.

[0057] At this time, the optical transceiver A2 enters a state where it has detected the transmission channel of the partner optical transceiver B2 and the channel available for transmission from the optical transceiver A2 to the optical transceiver B2 (state EK: Each CH Known), and the state transitions from EU to EK.

[0058] (9) SA0 / LA:CH3, RA:CH4, state transition:PK→EK Next, the optical transceiver A2 transmits a channel setting optical signal SA0 for channel CH3, in which the local channel information LA is fixed to channel CH3 and the remote channel information RA is fixed to channel CH4. The channel setting optical signal SA0 for channel CH3 is received by the optical transceiver B2.

[0059] In this case, the optical transceiver B2 can receive channel CH4 as the remote channel information RA of the optical transceiver A2. Since the remote channel information RA of the optical transceiver A2 is local channel information LB for the optical transceiver B2, the optical transceiver B2 fixes the local channel information LB to channel CH4. Note that fixing the local channel information LB to channel CH4 sets the transmission channel for the optical transceiver B2, so the optical transceiver B2 stops channel sweeping.

[0060] At this time, the optical transceiver B2 enters a state (state EK) in which it has detected the transmission channel of the partner optical transceiver A2 and a channel that can be transmitted from the optical transceiver B2 to the optical transceiver A2, and the state transitions from PK to EK.

[0061] (10)SB0 / LB:CH4,RB:CH3, State transition:EK→LE Next, the optical transceiver B2 transmits a channel setting optical signal SB0 for channel CH4, with the local channel information LB fixed to channel CH4 and the remote channel information RB fixed to channel CH3. The channel setting optical signal SB0 for channel CH4 is received by the optical transceiver A2.

[0062] In this case, the optical transceivers A2 and B2 can confirm that the local channel information LA of the optical transceiver A2 and the remote channel information RB of the optical transceiver B2 match channel CH3, and that the local channel information LB of the optical transceiver B2 and the remote channel information RA of the optical transceiver A2 match channel CH4. Therefore, in this case, the optical transceivers A2 and B2 can confirm that the channels to be used for transmission and reception have been determined. Therefore, since no further channel setting processing is required, the optical transceivers A2 and B2 conclude that the connection has been established (state LE: Link Established) and end the channel setting processing.

[0063] As a result, after the channel setting process is completed, the optical transceiver A2 and the optical transceiver B2 can transmit and receive optical signals using the channels CH3 and CH4.

[0064] As described above, according to this configuration, the optical transceiver can autonomously set the channel of the optical signal to be transmitted and the channel of the optical signal to be received by referring to the information contained in the channel setting signal that it receives.

[0065] This makes it possible to reduce the time required to set channels in the optical transceiver, even when many channels are used, such as in the optical communication system described above.

[0066] In manual channel configuration, it may take minutes, for example, about 10 minutes, to configure one channel. In contrast, with this configuration, although this may vary depending on the configuration of the optical communication system, automatic configuration of one channel is possible in seconds, for example, in a few seconds. As such, it can be seen that this configuration significantly reduces the time required to configure channels in an optical transceiver.

[0067] Furthermore, by having the optical transceiver autonomously perform channel setting, not only can manual work by the worker be reduced, but the worker can also perform other tasks while the channel setting process is in progress, which is advantageous in terms of labor savings.

[0068] Furthermore, since the optical transceiver can autonomously perform channel setting, it is possible to prevent mistakes such as setting the wrong channel, which can occur when channel setting is done manually, and it is also possible to improve the reliability of channel setting.

[0069] It is possible that an optical transmission device may be initially operated with fewer optical transceivers than the maximum number of optical transceivers installed, and then additional optical transceivers may be added. Manual channel configuration in this case requires cumbersome tasks, such as checking which channels are already in use and then configuring channels other than those already in use. In contrast, the optical transceiver according to the present embodiment can autonomously configure channels even if the channels already in use are unknown, thereby reducing the time and labor required for adding additional optical transceivers.

[0070] Although the above description focuses on the optical transceivers A2 and B2, it goes without saying that the channel setting process can be similarly performed for the other optical transceivers A1, A3 to A25, B1, and B3 to B25.

[0071] Although the above description has been given of the case where the optical transceiver changes the channel of the channel setting optical signal in ascending order starting from channel CH1, this is merely an example. For example, the optical transceiver may change the channel of the channel setting optical signal in descending order. Furthermore, for example, the optical transceiver may change the channel of the channel setting optical signal in any order other than descending or ascending order.

[0072] Other embodiments The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the optical transmission device may be connected to various networks including trunk routes and branch routes, in addition to the network shown in FIG.

[0073] The number of optical transceivers and the number of channels provided in the optical transmission device are merely examples, and any number of optical transceivers and any number of channels may be provided.

[0074] In the above-described embodiment, it has been described that wavelength multiplexed signals are transmitted between optical transmission devices, but it goes without saying that various multiplexing methods other than wavelength multiplexing can be applied to the transmitted optical signals, and various modulation methods can be applied.

[0075] The configuration of the optical transceiver described above is simplified in order to explain the optical transceiver according to the above embodiment, and it goes without saying that it may include various components, such as a CDR (Clock Data Recovery) unit.

[0076] In the above description, an example has been described in which an optical signal obtained by on / off modulation is used as the channel setting optical signal, but an optical signal obtained by phase shift keying other than on / off modulation may also be used as the channel setting optical signal.

[0077] In the above-described embodiment, the present invention has been described as being configured as hardware, but the present invention is not limited to this. The present invention can also be realized by having a central processing unit (CPU) execute a computer program to control the wavelength-tunable optical transmitter and receiver by a control unit and to perform the channel setting process shown in FIGS. 8 and 9 . The above-described program can be stored on various types of non-transitory computer-readable media and supplied to a computer. Non-transitory computer-readable media include various types of tangible storage media. Examples of 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-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and random access memories (RAMs)). The program can also be supplied to a computer by various types of transitory computer-readable media. Examples of the temporary computer-readable medium include an electric signal, an optical signal, and an electromagnetic wave. The temporary computer-readable medium can provide the program to the computer via a wired communication path such as an electric wire or an optical fiber, or via a wireless communication path.

[0078] The present invention has been described above, but it can also be described as follows.

[0079] (Supplementary Note 1) An optical transceiver comprising: a wavelength-tunable optical transmitter configured to be able to transmit a first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; a wavelength-tunable optical receiver that, when receiving a second channel setting optical signal from another optical transceiver, transfers second channel information that is included in the second channel setting optical signal and indicates the channel of the second channel setting optical signal; and a control unit that controls the wavelength-tunable optical transmitter and the wavelength-tunable optical receiver, wherein the control unit sets the first channel indicated by the second channel information as the channel of an optical signal received by the wavelength-tunable optical receiver, based on the second channel information transferred by the wavelength-tunable optical receiver.

[0080] (Supplementary Note 2) The optical transceiver described in Supplementary Note 1, wherein the control unit controls the wavelength-tunable optical transmitting unit so that the first channel information and third channel information indicating the first channel are included in the first channel setting optical signal.

[0081] (Supplementary Note 3) The optical transceiver described in Supplementary Note 2, wherein when the second channel setting optical signal includes the second channel information and fourth channel information indicating the second channel based on the third channel information indicating a second channel different from the first channel and included in the first channel setting optical signal by the other optical transceiver, the wavelength-tunable optical receiving unit transfers the fourth channel information, and the control unit sets the second channel as the channel of the optical signal to be transmitted by the wavelength-tunable optical transmitting unit based on the fourth channel information transferred by the wavelength-tunable optical receiving unit.

[0082] (Supplementary Note 4) The optical transceiver according to Supplementary Note 3, wherein the control unit controls the wavelength-tunable optical transmitting unit to stop transmitting the first channel setting optical signal.

[0083] (Supplementary Note 5) An optical transceiver described in any one of Supplementary Notes 1 to 4, wherein, when the control unit is not receiving the second channel setting optical signal, the control unit changes the channel of the first channel setting optical signal to a channel that has not yet been set as the channel of the first channel setting optical signal, and outputs the first channel setting optical signal.

[0084] (Supplementary Note 6) The optical transceiver according to any one of Supplementary Notes 1 to 5, wherein the control unit controls the first and second channel setting optical signals to be on / off modulated optical signals.

[0085] (Appendix 7) An optical transceiver as described in Appendix 6, wherein the wavelength-tunable optical transmitter unit has a driver that outputs a drive signal corresponding to an input signal, and a wavelength-tunable optical output unit that outputs an optical signal modulated according to the drive signal, and the control unit controls the driver so that the first channel setting optical signal that has been on / off modulated according to the drive signal is output from the wavelength-tunable optical output unit.

[0086] (Supplementary Note 8) A first optical transmission device having a plurality of optical transceivers including a first optical transceiver and a first optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels; a second optical transmission device having a plurality of optical transceivers including a second optical transceiver and a second optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels; and an optical cable connecting the first optical transmission device and the second optical transmission device, wherein the first optical transceiver is configured to set a first channel using a first optical signal. a wavelength-tunable optical transmitting unit configured to be able to transmit a first channel setting optical signal including first channel information indicating a channel of the optical signal; a wavelength-tunable optical receiving unit configured to transfer second channel information indicating a channel of the second channel setting optical signal, the second channel information being included in the second channel setting optical signal when the second channel setting optical signal is received from the second optical transceiver; and a control unit configured to control the wavelength-tunable optical transmitting unit and the wavelength-tunable optical receiving unit, wherein the control unit sets the first channel indicated by the second channel information as a channel of the optical signal received by the wavelength-tunable optical receiving unit, based on the second channel information transferred by the wavelength-tunable optical receiving unit.

[0087] (Supplementary Note 9) An optical transmission device comprising: a plurality of optical transceivers; and an optical multiplexer / demultiplexer that multiplexes and outputs optical signals output by the plurality of optical transceivers and demultiplexes received optical signals to the plurality of optical transceivers according to channels, wherein each of the plurality of optical transceivers comprises: a tunable optical transmitter configured to be able to transmit the first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; a tunable optical receiver that, when receiving a second channel setting optical signal from another optical transceiver provided in another optical transmission device, transfers second channel information that indicates a channel of the second channel setting optical signal, the second channel information being included in the second channel setting optical signal; and a control unit that controls the tunable optical transmitter and the tunable optical receiver, wherein the control unit sets the first channel indicated by the second channel information as the channel of the optical signal received by the tunable optical receiver, based on the second channel information transferred by the tunable optical receiver.

[0088] (Supplementary Note 10) A method for configuring an optical transceiver, comprising: transmitting a first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; upon receiving a second channel setting optical signal from another optical transceiver, forwarding second channel information indicating the channel of the second channel setting optical signal, which is included in the second channel setting optical signal; and setting the first channel indicated by the second channel information as the channel of the optical signal to be received based on the forwarded second channel information.

[0089] (Supplementary Note 11) In an optical transceiver having a control unit configured as an arithmetic unit capable of controlling a wavelength-tunable optical transmitting unit and a wavelength-tunable optical receiving unit, a non-transitory computer-readable medium storing a program that causes the control unit to execute the following operations: transmitting from the wavelength-tunable optical transmitting unit a first channel setting optical signal including first channel information indicating a channel of the first channel setting optical signal; transferring by the wavelength-tunable optical receiving unit, second channel information indicating a channel of the second channel setting optical signal, which is included in the second channel setting optical signal, when receiving a second channel setting optical signal from another optical transceiver; and setting by the control unit, the first channel indicated by the second channel information, as a channel of an optical signal received by the wavelength-tunable optical receiving unit, based on the second channel information transferred by the wavelength-tunable optical receiving unit.

[0090] Although the present invention has been described above with reference to the embodiments, 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]

[0091] 1, 2 Optical transmission equipment 10. Tunable wavelength optical transmitter 11 Drive unit 12 Optical signal transmitter 20 Tunable wavelength optical receiver 21 Amplification section 22 Optical signal receiving unit 30 Control Unit 100, A1~A25, B1~B25 Optical Transceiver 1000 Optical Communication Systems AMP Optical Amplifier BS1, BS2 terminal station C1, C2 optical cables CON control signal DAT output signal DET detection signal DRV drive signal IN main signal INS command signal L, LA, LB local channel information LS1, LS2 optical signal M1, M2 optical multiplexer / demultiplexer OH header information OUT Output signal R, RA, RB Remote channel information S, SA, SA0 to SA4, SB, SB0 to SB4 Optical signals for channel setting

Claims

1. An optical transceiver comprising an optical transmitter and an optical receiver, the optical transceiver autonomously executes a channel setting process when the optical transceiver is attached to an optical transmission device; In the channel setting process, the optical transmitter transmits the first transmission optical signal including first transmission channel information indicating a channel of the first transmission optical signal; the optical receiving unit receives the first received optical signal including first reception channel information indicating a channel of the first received optical signal; the optical transmitter transmits the second transmission optical signal including second transmission channel information indicating a channel of the second transmission optical signal and the first reception channel information; Optical transceiver.

2. Further comprising a control unit that transfers first reception channel information, which is transferred by the optical receiving unit when the optical receiving unit receives the first reception optical signal, to the optical transmitting unit.

10. The optical transceiver of claim 1.

3. the optical receiving unit, when the first received optical signal includes setting channel information, which is one of the first transmission channel information and the second transmission channel information, and the first reception channel information, transfers the setting channel information; the control unit sets a channel of the optical signal to be transmitted by the optical transmitting unit based on the set channel information.

3. The optical transceiver according to claim 2.

4. When the optical receiving unit receives the first received optical signal, the control unit sets a channel of the optical signal received by the optical receiving unit based on the first received channel information included in the first received optical signal.

3. The optical transceiver according to claim 2.

5. the optical transmitting unit changes the channel of the first transmission optical signal to a channel that has not yet been set as the channel of the first transmission optical signal and outputs the first transmission optical signal until the optical receiving unit receives the first reception optical signal.

5. The optical transceiver according to claim 1.

6. The optical transmitting unit stops changing the channel of the first transmitting optical signal after the optical receiving unit receives the first receiving optical signal.

6. The optical transceiver according to claim 5.

7. A first optical transmission device to which a first optical transceiver can be attached; a second optical transmission device to which a second optical transceiver can be attached; an optical cable connecting the first optical transmission device and the second optical transmission device; the first optical transceiver includes an optical transmitting unit and an optical receiving unit; the first optical transceiver autonomously performs a channel setting process when the first optical transceiver is attached to the first optical transmission device; In the channel setting process, the optical transmitter transmits the first transmission optical signal to the second optical transceiver, the first transmission optical signal including first transmission channel information indicating a channel of the first transmission optical signal; the optical receiving unit receives the first received optical signal from the second optical transceiver, the first received optical signal including first received channel information indicating a channel of the first received optical signal; the optical transmitter transmits the second transmission optical signal, which includes second transmission channel information indicating a channel of the second transmission optical signal and the first reception channel information, to the second optical transceiver; Optical communication system.

8. 1. A method for an optical transceiver attachable to an optical transmission device, comprising: When the optical transceiver is attached to the optical transmission device, the optical transceiver autonomously executes a channel setting process; In the channel setting process, transmitting a first transmission optical signal including first transmission channel information indicating a channel of the first transmission optical signal; receiving a first received optical signal including first received channel information indicating a channel of the first received optical signal; transmitting a second transmission optical signal including second transmission channel information indicating a channel of the second transmission optical signal and the first reception channel information; Methods relating to optical transceivers.

9. An optical transceiver having a control unit capable of controlling an optical transmitting unit and an optical receiving unit, and capable of being attached to an optical transmission device, a process of autonomously executing a channel setting process when the optical transceiver is attached to the optical transmission device; In the channel setting process, transmitting a first transmission optical signal including first transmission channel information indicating a channel of the first transmission optical signal; receiving a first received optical signal including first received channel information indicating a channel of the first received optical signal; transmitting a second transmission optical signal including second transmission channel information indicating a channel of the second transmission optical signal and the first reception channel information; causing the control unit to execute program.

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