Operation device

Abstract

To access, monitor and manage a user-side optical communication device that has only a communication path of an optical transmission line for transmitting and receiving a main signal, without using a communication path other than the communication path.SOLUTION: An operation device includes a transmission path design unit that performs a transmission mode identification process to identify a transmission mode to be used in communication between a first optical communication device and a second optical communication device on the basis of transmission path information of a first optical transmission path connecting a first node device to which the first optical communication device is connected and a second node device to which the second optical communication device is connected, and available resource information of the first optical transmission path.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to an operation device. [Background technology]

[0002] As digital signal processing for optical transmission, i.e., DSP (Digital Signal Processor), becomes more sophisticated, various parameters related to transmission performance, such as modulation methods, baud rate, type of error correction code such as FEC (Forward Error Correction), number of carriers, etc., are increasing, and transmission modes are becoming more diverse. In response to this, proposals have been made for technologies to select the optimal transmission mode from among transmission modes determined by a combination of multiple parameters related to transmission performance, as well as messaging methods for selecting the optimal transmission mode.

[0003] For example, Patent Document 1 discloses a method for selecting an optimal modulation method based on a training signal. Patent Document 2 discloses a messaging method for selecting an optimal transmission mode in response to various parameters related to transmission performance, such as baud rate, type of error correction code, and number of carriers, other than the modulation method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5753604 [Patent Document 2] International Publication No. 2020 / 031514 Summary of the Invention [Problem to be solved by the invention]

[0005] Suppose that, using the technologies described in Patent Documents 1 and 2, an optical path, i.e., an optical route for transmitting a main signal optical signal, can be opened by selecting an optimal transmission mode from among multiple transmission modes in an optical transmission path connecting two points within a carrier network operated by a telecommunications carrier, or in an optical transmission path connecting two user locations via a carrier network. In such a configuration, the only communication path present in a user-side optical communication device, such as a transponder device installed at the user location, is the optical transmission path for transmitting and receiving the main signal, unless the device is connected to another communication network. Therefore, for example, if a fault occurs in the optical path, an operation device that monitors and manages the user-side optical communication device cannot access the user-side optical communication device to obtain notification information such as an alarm indicating a device malfunction or communication failure occurring in the user-side optical communication device, or information necessary for fault recovery, such as information about the transmission mode set in the user-side optical communication device. Another monitoring and management issue is that it cannot send a control signal to the user-side optical communication device to instruct it to stop transmitting the main signal in order to recover from the fault.

[0006] In view of the above circumstances, the present invention aims to provide a technology that enables a user-side optical communication device that has only an optical transmission path for transmitting and receiving a main signal to be accessed and monitored or managed without using a communication path other than the communication path. [Means for solving the problem]

[0007] One aspect of the present invention is an optical transmission system comprising a connection node apparatus, a user-side optical communication apparatus, a first optical transmission path connecting the connection node apparatus and the user-side optical communication apparatus, and a second optical transmission path connected to the connection node apparatus, wherein the connection node apparatus comprises a node-side control signal transmitting / receiving unit for transmitting and receiving control signals, and wavelength-multiplexes a control signal transmitted by the node-side control signal transmitting / receiving unit and a main signal received via the second optical transmission path, and transmits the multiplexed control signal to the first optical transmission path, wavelength-separates the optical signal received via the first optical transmission path into the control signal and the main signal, and outputs the separated control signal to the node-side control signal transmitting / receiving unit, and a node-side control signal multiplexing / demultiplexing unit that transmits the separated main signal to the second optical transmission path, and the user-side optical communication device comprises an optical transceiver that transmits and receives the main signal, a user-side control signal transceiver that transmits and receives the control signal, and a user-side control signal multiplexing / demultiplexing unit that wavelength-multiplexes the control signal transmitted by the user-side control signal transceiver and the main signal transmitted by the optical transceiver and transmits them to the first optical transmission path, wavelength-demultiplexes the optical signal received via the first optical transmission path into the control signal and the main signal, outputs the separated control signal to the user-side control signal transceiver and outputs the separated main signal to the optical transceiver.

[0008] One aspect of the present invention is a control signal transmission / reception method in an optical transmission system including a connection node apparatus, a user-side optical communication apparatus, a first optical transmission path connecting the connection node apparatus and the user-side optical communication apparatus, and a second optical transmission path connecting the connection node apparatus, wherein a node-side control signal transmission / reception unit transmits a control signal, a node-side control signal multiplexing / demultiplexing unit wavelength-multiplexes a control signal transmitted by the node-side control signal transmission / reception unit and a main signal received via the second optical transmission path, and sends the multiplexed signal to the first optical transmission path, and a user-side control signal multiplexing / demultiplexing unit wavelength-demultiplexes an optical signal received via the first optical transmission path into the control signal and the main signal, and outputs the separated control signal to the user-side control signal transmission / reception unit, and outputs the separated main signal to the optical transmission / reception unit. the optical transceiver receives the main signal, the user-side control signal transceiver receives the control signal, the optical transceiver transmits the main signal, the user-side control signal transceiver transmits the control signal, the user-side control signal multiplexing / demultiplexing unit wavelength-multiplexes the control signal transmitted by the user-side control signal transceiver and the main signal transmitted by the optical transceiver and sends them out to the first optical transmission path, the node-side control signal multiplexing / demultiplexing unit wavelength-demultiplexes the optical signal received via the first optical transmission path into the control signal and the main signal, outputs the separated control signal to the node-side control signal transceiver and sends out the separated main signal to the second optical transmission path, and the node-side control signal transceiver receives the control signal. [Effects of the Invention]

[0009] According to the present invention, for a user-side optical communication device that only has a communication path of an optical transmission line for transmitting and receiving a main signal, it is possible to access the user-side optical communication device and perform monitoring and management without using a communication path other than the communication path. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of an optical transmission system according to a first embodiment. [Figure 2]1 is a diagram (part 1) showing the internal configurations of a connection node apparatus and an optical communication apparatus according to the first embodiment, and the connection relationship of optical transmission paths in each of the connection node apparatus and the optical communication apparatus. FIG. [Figure 3] FIG. 2 is a diagram illustrating a processing flow of the optical transmission system according to the first embodiment. [Figure 4] FIG. 2 is a diagram (part 2) showing the internal configurations of a connection node apparatus and an optical communication apparatus according to the first embodiment, and the connection relationship of optical transmission paths in each of the connection node apparatus and the optical communication apparatus. [Figure 5] FIG. 10 is a block diagram showing the configuration of an optical transmission system according to a second embodiment. [Figure 6] FIG. 10 is a diagram illustrating a processing flow of an optical transmission system according to the second embodiment. [Figure 7] FIG. 10 is a diagram illustrating another configuration example (part 1) of the optical transmission system according to the second embodiment. [Figure 8] FIG. 10 is a block diagram showing a configuration of an optical transmission system according to a third embodiment. [Figure 9] FIG. 10 is a diagram (part 1) showing the internal configurations of a connection node apparatus and an optical communication apparatus according to a third embodiment, and the connection relationship of optical transmission paths in each of the connection node apparatus and the optical communication apparatus. [Figure 10] FIG. 10 is a diagram illustrating a processing flow of an optical transmission system according to the third embodiment. [Figure 11] FIG. 11 is a diagram (part 2) showing the internal configurations of a connection node apparatus and an optical communication apparatus according to the third embodiment, and the connection relationship of optical transmission paths in each of the connection node apparatus and the optical communication apparatus. [Figure 12] FIG. 13 is a diagram (part 3) showing the internal configurations of a connection node apparatus and an optical communication apparatus according to the third embodiment, and the connection relationship of optical transmission paths in each of the connection node apparatus and the optical communication apparatus. [Figure 13] FIG. 10 is a diagram illustrating another configuration example (part 1) of the optical transmission system according to the third embodiment. [Figure 14] FIG. 10 is a diagram illustrating another configuration example (part 2) of the optical transmission system according to the second embodiment. [Figure 15]FIG. 10 is a diagram illustrating another configuration example (part 2) of the optical transmission system according to the third embodiment. [Figure 16] FIG. 10 is a diagram illustrating another configuration example (part 3) of the optical transmission system according to the second embodiment. [Figure 17] FIG. 10 is a block diagram showing a configuration of an optical transmission system according to a fourth embodiment. [Figure 18] FIG. 13 is a diagram illustrating a data configuration of a connection status table of a transmission path design unit in the fourth embodiment. [Figure 19] FIG. 10 is a diagram showing a processing flow of an optical transmission system according to the fourth embodiment. [Figure 20] FIG. 13 is a diagram showing the flow of a transmission mode specifying process in the fourth embodiment. [Figure 21] FIG. 11 is a block diagram (part 1) illustrating a configuration of an optical transmission system according to a fifth embodiment. [Figure 22] FIG. 13 is a block diagram (part 2) illustrating the configuration of an optical transmission system according to the fifth embodiment. [Figure 23] FIG. 13 is a block diagram (part 3) illustrating the configuration of an optical transmission system according to the fifth embodiment. [Figure 24] FIG. 13 is a diagram illustrating an example of a data format of a path management table in the fifth embodiment. [Figure 25] FIG. 13 is a diagram illustrating an example of a data format of a control signal transmitting / receiving unit correspondence table in the fifth embodiment. [Figure 26] FIG. 13 illustrates an example of processing performed by the optical transmission system according to the fifth embodiment. [Figure 27] FIG. 13 is a block diagram showing the configuration of an optical transmission system according to a sixth embodiment. [Figure 28] FIG. 13 is a block diagram showing the configuration of an optical transmission system according to another configuration example of the sixth embodiment. [Figure 29] FIG. 13 is a block diagram showing the configuration of an optical transmission system according to a seventh embodiment. [Figure 30] FIG. 23 is a diagram illustrating an example of a data format of a path management table in the seventh embodiment. [Figure 31]FIG. 20 is a diagram illustrating an example of a data format of an optical communication device table according to the seventh embodiment. [Figure 32] FIG. 13 is a diagram (part 1) showing another example of the configuration of the connection relationship between the control signal multiplexing / demultiplexing unit and the output port switching unit in the seventh embodiment. [Figure 33] FIG. 20 is a diagram (part 2) illustrating another example of the configuration of the connection relationship between the control signal multiplexing / demultiplexing unit and the output port switching unit in the seventh embodiment. [Figure 34] FIG. 13 is a block diagram showing the configuration of an optical transmission system according to an eighth embodiment. [Figure 35] FIG. 20 is a diagram illustrating an example of a data format of a path management table according to the eighth embodiment. [Figure 36] FIG. 13 is a diagram (part 1) illustrating an example of processing by the optical transmission system according to the eighth embodiment. [Figure 37] FIG. 20 is a diagram (part 2) illustrating an example of processing by the optical transmission system according to the eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described. The problem to be solved by the present invention is the "problem related to monitoring and management" as described above. In contrast, the technologies described in Patent Documents 1 and 2 have the "problem related to connection" as described below, and the first to fourth embodiments show embodiments that solve this "problem related to connection." The fifth embodiment shows a basic embodiment that solves the "problem related to monitoring and management," and the sixth to eighth embodiments show embodiments that solve the "problem related to monitoring and management" in the configurations shown in the first to fourth embodiments, respectively.

[0012] Here, we will explain the "connection-related issues" of the technologies described in Patent Documents 1 and 2. The technologies described in Patent Documents 1 and 2 are unable to select an optimal transmission mode when setting an optical path, i.e., an optical route, that passes through multiple optical transmission paths, such as dark fiber and optical transmission paths of a carrier network. In other words, when setting an optical route through multiple optical transmission paths, such as dark fiber and a carrier network, it is necessary to manually measure the characteristics of the dark fiber from a user terminal device installed in a data center or the like to an edge terminal device of the carrier network. This poses a problem of cost and time required to set up an optical route between users. Because some of the resources available within the carrier network are used for other communications, there are limitations on the resources available for setting up an optical route, and this resource limitation must also be taken into consideration when setting up an optical route between users.

[0013] The first to fourth embodiments described below are embodiments that aim to connect optical transmitters and receivers provided in an optical communication device via multiple optical transmission paths without manual intervention using an optical path of the optimal transmission mode.

[0014] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an optical transmission system 100 in a first embodiment. The optical transmission system 100 includes a connecting node apparatus 1, optical communication apparatus 2X, optical communication apparatus 2Y, optical transmission paths 51, 52, and a connecting line 3. The optical transmission path 51 connects the optical communication apparatus 2X and the connecting node apparatus 1. The optical transmission path 52 connects the optical communication apparatus 2Y and the connecting node apparatus 1. The connecting line 3 connects the connecting node apparatus 1 and the optical communication apparatus 2Y. The optical communication apparatus 2X is, for example, a communication apparatus used by a user. The optical communication apparatus 2Y is, for example, an optical transmission apparatus owned by a telecommunications carrier, i.e., a node apparatus in a communication network, or a white-box transponder owned by a telecommunications carrier or a data center operator.

[0015] The internal configurations of the connection node device 1, the optical communication device 2X, and the optical communication device 2Y will be described with reference to Fig. 2 in addition to Fig. 1. Among the connection lines shown in Fig. 1 and Fig. 2, the solid lines with thin arrows indicate paths for electrical data signals, the solid lines with thick arrows indicate paths for optical data signals, the dashed lines with thin arrows indicate paths for electrical control signals, the thin solid lines indicate electrical connections, the thick solid lines indicate connections by optical lines, and the dashed dotted lines indicate connection lines, and the same applies to other figures unless otherwise defined.

[0016] The optical transmission path 51 shown in FIG. 1 includes, for example, optical fibers 51T and 51R such as dark fibers, as shown in FIG. 2. Here, in order to distinguish between the two optical fibers included in the optical transmission path 51, for convenience of explanation, the letters "T" and "R" are added to the symbol "51", and the symbol "T" means the transmission direction as seen from the optical communication device 2X and the reception direction as seen from the connecting node equipment 1 and the optical communication device 2Y. The symbol "R" means the reception direction as seen from the optical communication device 2X and the transmission direction as seen from the connecting node equipment 1 and the optical communication device 2Y. The optical transmission path 52 shown in FIG. 1 includes, for example, optical fibers 52T and 52R that constitute a carrier network owned by a telecommunications carrier, as shown in FIG. 2. The connection line 3 is a communication line, and may be, for example, a wired communication line such as a dedicated line, a wireless communication line, a communication network such as a mobile communication network or the Internet network, or a DCN (Data Communication Network).In the case of a connection via an optical communication line, a portion of the overhead area of ​​the digital frame transferred by optical signal may be allocated as the connection line 3.

[0017] The optical communication device 2X is, for example, a transponder that transmits data provided from an external device and outputs received data to the external device. As shown in Fig. 2, the optical communication device 2X includes a control unit 20X and an optical transceiver unit 21X. The control unit 20X is connected to the optical transceiver unit 21X and controls the optical transceiver unit 21X and inputs and outputs information to and from the optical transceiver unit 21X. The control unit 20X generates a connection request instruction signal, for example, when starting a connection to the optical transceiver unit 21Y included in the optical communication device 2Y.

[0018] The optical transceiver 21X includes an IF (Interface) unit 22X, an optical transmitter 24X, an optical receiver 27X, a digital signal processor 23X, and a controller 71X. The IF unit 22X connects an optical fiber 51T of the optical transmission line 51 to the optical transmitter 24X. The IF unit 22X connects an optical fiber 51R of the optical transmission line 51 to the optical receiver 27X.

[0019] When the control unit 71X receives a connection request instruction signal from the control unit 20X, it generates data indicating a connection request (hereinafter referred to as "connection request data"). Here, the connection request data is data including information such as a destination address, a source address, a desired bit rate, and specifications of the optical transceiver unit 21X. The specification information of the optical transceiver unit 21X is information including, for example, a modulation method usable by the optical transmitter unit 24X, an FEC type usable by the digital signal processor 23X, a baud rate, and the type of light source provided in the optical transmitter unit 24X.

[0020] Here, the information indicating the type of light source is, for example, information indicating whether the light source is of a type that outputs a predetermined single wavelength or a type that outputs a variable wavelength, and further information including, in addition to the above information, information on the wavelength or wavelength band that the light source can output. In the case of the optical communication device 2X, the optical transmitter 24X includes a single-wavelength light source 25X. Therefore, the specification information of the optical transceiver 21X includes information that the light source included in the optical transmitter 24X is of a type that outputs a predetermined single wavelength, and information indicating the wavelength that the light source can output.

[0021] The optical transceiver 21X included in the optical communication device 2X and the optical transceiver 21Y included in the optical communication device 2Y are assigned address information in advance to identify each of them. The control unit 20X stores a desired bit rate and address information of the connection destination in an internal storage area in advance. The control unit 71X stores address information assigned to the optical transceiver 21X included in itself in an internal storage area in advance. For example, when the optical transceiver 21X is installed in the optical communication device 2X, the control unit 71X acquires specification information of the optical transceiver 21X from the optical transmitter 24X and the digital signal processing unit 23X and stores the information in an internal storage area. The control unit 20X may acquire address information of the connection destination specified by a user of the optical communication device 2X, for example, rather than storing the address information of the connection destination in an internal storage area in advance. The control unit 20X may receive an input operation from the user and acquire data of a bit rate designated in advance by the user as the desired bit rate, rather than storing the desired bit rate in an internal storage area in advance.

[0022] For example, when requesting a connection to an optical transceiver 21Y included in the optical communication device 2Y, the control unit 20X generates a connection request instruction signal including address information of the optical transceiver 21Y and a desired bit rate and outputs the signal to the control unit 71X. The control unit 71X reads the address information of the optical transceiver 21Y included in the connection request instruction signal received from the control unit 20X and sets it as destination address information, and reads address information of the optical transceiver 21X stored in an internal storage area and sets it as source address information. The control unit 71X generates connection request data including the destination address information and source address information determined as above, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21X stored in an internal storage area. The control unit 71X outputs the generated connection request data to the digital signal processing unit 23X.

[0023] The digital signal processing unit 23X is, for example, a DSP, and is connected to the control unit 71X, the optical transmitting unit 24X, and the optical receiving unit 27X. The digital signal processing unit 23X receives transmission data, such as a client signal, provided from an external device connected to the optical communication device 2X. The digital signal processing unit 23X receives connection request data generated by the control unit 71X.

[0024] The digital signal processing unit 23X generates a transmission data signal in a transmission frame format that includes the captured transmission data in its payload. The digital signal processing unit 23X generates the transmission data signal so that the captured connection request data is included in an empty area in the overhead of the transmission frame. Note that the digital signal processing unit 23X may generate the transmission data signal so that the transmission data is not included in the payload, so as not to transmit the transmission data before the transmission mode information is determined. The digital signal processing unit 23X outputs the generated transmission data signal to the optical transmitting unit 24X.

[0025] The digital signal processing unit 23X receives the received data signal, which is an electrical signal output by the optical receiving unit 27X. The digital signal processing unit 23X reads data contained in the payload and overhead of the received data signal. The digital signal processing unit 23X outputs the client signal contained in the read data to an external device. The digital signal processing unit 23X outputs connection request data contained in the read data and control information contained in the overhead to the control unit 71X. The control unit 71X outputs an electrical control signal to the single-wavelength light source 25X and the optical modulator 26X, as indicated by the dashed arrows.

[0026] The optical transmitter 24X includes a single-wavelength light source 25X and an optical modulator 26X. The single-wavelength light source 25X generates and outputs continuous light of a predetermined single wavelength at an optical power specified by a control signal (hereinafter referred to as an "output optical power specification signal") indicating the output optical power output by the controller 71X. The optical modulator 26X optically modulates the continuous light output by the single-wavelength light source 25X in accordance with a modulation method specified by a control signal (hereinafter referred to as a "modulation method specification signal") specifying the modulation method output by the controller 71X, based on the transmission data signal output by the digital signal processor 23X. The optical modulator 26X outputs the optical signal generated by the optical modulation to the IF unit 22X.

[0027] The optical receiving unit 27X includes an optical receiver 28X. The optical receiver 28X is, for example, a photodiode (PD), and receives the optical signal output by the IF unit 22X and converts the received optical signal into an electrical signal, for example, by detecting the optical intensity of the signal. The optical receiver 28X outputs the electrical signal converted from the optical signal to the digital signal processing unit 23X as a received data signal.

[0028] The optical communication device 2Y has the same functional units as the optical communication device 2X. Hereinafter, when referring to each functional unit provided in the optical communication device 2Y, the "X" included in the reference numeral attached to each functional unit provided in the optical communication device 2X will be replaced with "Y".

[0029] The connection node device 1 comprises an edge function unit 11 and an output port switching unit 14. The output port switching unit 14 comprises optical switch units 15T and 15R, which are, for example, FiberPatchPanels. The optical switch unit 15T connects an optical fiber 51T, the edge function unit 11, and an optical fiber 52T provided in an optical transmission path 52. The optical switch unit 15T performs switching processing to switch the connection destination of the optical fiber 51T to either the edge function unit 11 or the optical fiber 52T. The optical switch unit 15R connects the optical fiber 51R, the edge function unit 11, and an optical fiber 52R provided in the optical transmission path 52. The optical switch unit 15R performs switching processing to switch the connection destination of the optical fiber 51R to either the edge function unit 11 or the optical fiber 52R.

[0030] The edge function unit 11 includes a control unit 12 and a connection information processing unit 13. The connection information processing unit 13 includes an IF unit 31, a digital signal processing unit 32, an optical receiving unit 33, an optical transmitting unit 35, and a connection information generation unit 38. The IF unit 31 connects the optical switch unit 15T and the optical receiving unit 33. The IF unit 31 connects the optical switch unit 15R and the optical transmitting unit 35.

[0031] The optical receiving unit 33 includes an optical receiver 34. The optical receiver 34 is, for example, a PD, which receives the optical signal output by the IF unit 31 and converts the received optical signal into an electrical signal, for example, by detecting the optical intensity of the signal. The optical receiver 34 outputs the electrical signal converted from the optical signal to the digital signal processing unit 32 as a received data signal.

[0032] The optical transmitting unit 35 includes a single-wavelength light source 36 and an optical modulator 37. The single-wavelength light source 36 generates and outputs continuous light of a predetermined single wavelength, which is continuous light of a fundamental output optical power in a fundamental mode specified by the control unit 12. Here, the fundamental mode is a transmission mode that is predetermined by a predetermined fundamental output optical power, a fundamental modulation method, a fundamental wavelength, etc., and the control unit 12, the control unit 71X of the optical communication device 2X, and the control unit 71Y of the optical communication device 2Y store information related to the fundamental mode in advance in internal storage areas.

[0033] The wavelength of the single-wavelength light source 36, the wavelength of the single-wavelength light source 25X included in the optical communication device 2X, and the wavelength of the single-wavelength light source 25Y included in the optical communication device 2Y are all fundamental wavelengths determined in advance in the fundamental mode. However, these wavelengths are not necessarily limited to the same wavelength value called the fundamental wavelength, and the wavelength of the single-wavelength light source 36 and the wavelength of the single-wavelength light source 25Y included in the optical communication device 2Y may be within a wavelength range that can be received by the optical receiver 28X included in the optical communication device 2X. The wavelength of the single-wavelength light source 25X included in the optical communication device 2X may be within a wavelength range that can be received by the optical receiver 28Y included in the optical communication device 2Y and the optical receiver 34 of the connecting node device 1.

[0034] The optical modulator 37 optically modulates the continuous light output from the single-wavelength light source 36 in accordance with the basic modulation method of the basic mode specified by the control unit 12, based on the transmission data signal output from the digital signal processing unit 32.

[0035] The digital signal processing unit 32 is, for example, a DSP, and is connected to the optical receiving unit 33 and the optical transmitting unit 35. The digital signal processing unit 32 takes in a received data signal output by an optical receiver 34 of the optical receiving unit 33. If the received data signal output by the optical receiver 34 includes connection request data transmitted by the optical communication device 2X, the digital signal processing unit 32 reads and acquires the connection request data from the received data signal. The digital signal processing unit 32 generates a transmission data signal and outputs the transmission data signal to the optical modulator 37.

[0036] The connection information generation unit 38 calculates and obtains transmission path information of the optical fiber 51T of the optical transmission path 51 based on the received data signal captured by the digital signal processing unit 32, for example, by a predetermined calculation disclosed in Reference 1 below.

[0037] [Reference 1: Takeo Sasai, et al, “Simultaneous Detection of Anomaly Points and Fiber Types in Multi-Span Transmission Links Only by Receiver-Side Digital Signal Processing”, OFC 2020: 1-3]

[0038] Here, the transmission path information of the optical fiber 51T refers to information including the loss of the optical fiber 51T provided in the optical transmission path 51, the gain of the amplifier inserted in the optical transmission path 51, the NF (Noise Figure) of the amplifier, the fiber type of the optical fiber 51T, etc. The connection information generation unit 38 acquires the BER (Bit Error Rate) of the optical transmission path 51 acquired by the digital signal processing unit 32 from the received data signal, and generates connection information including the acquired BER of the optical transmission path 51 and the calculated transmission path information of the optical fiber 51T. Note that the digital signal processing unit 32 may acquire information for calculating the BER instead of the BER, and the connection information generation unit 38 may calculate the BER based on the information for calculating the BER acquired by the digital signal processing unit 32, and include the calculated BER in the connection information. The digital signal processing unit 32 may acquire a quality factor (Q factor), polarization mode dispersion (PMD), chromatic dispersion (CD), and optical signal-to-noise ratio (OSNR) in addition to the BER and output the information to the connection information generation unit 38, so that the Q factor, PMD, CD, and OSNR are included in the connection information. The digital signal processing unit 32 outputs a transmission data signal, which is an electrical signal, to the optical modulator 37. The connection information generation unit 38 outputs the connection request data that the digital signal processing unit 32 reads from the received data signal and the generated connection information to the control unit 12.

[0039] The control unit 12 stores in advance in an internal storage area a route information table that associates address information of the optical transceivers 21X, 21Y included in each of the optical communication devices 2X, 2Y connected to the connection node device 1 with identification information that identifies the optical transmission path corresponding to the address information. Note that the control unit 12 may obtain the route information table on demand from an external device, rather than storing it in advance in an internal storage area. For example, in the optical transmission system 100, in the route information table, identification information that identifies the optical transmission path 51 is associated with address information of the optical transceiver 21X of the optical communication device 2X, and identification information that identifies the optical transmission path 52 is associated with address information of the optical transceiver 21Y of the optical communication device 2Y.

[0040] The control unit 12 refers to the route information table and detects identification information that identifies the optical transmission path corresponding to the destination address information included in the connection request data output by the digital signal processing unit 32. However, in the first embodiment, in the route information table, the address information of the optical transceiver 21Y is associated with identification information that identifies the optical transmission path 52, and the optical communication device 2X is configured to select only the optical transceiver 21Y as the connection destination. Therefore, the control unit 12 always detects identification information that identifies the optical transmission path 52, and the following description will be given on the assumption that the control unit 12 detects identification information that identifies the optical transmission path 52.

[0041] The control unit 12 stores transmission path information of the optical transmission path 52 in an internal storage area in association with identification information that identifies the optical transmission path 52. Here, the transmission path information of the optical transmission path 52 is information including, as in the case of the optical transmission path 51 described above, the loss of the optical fibers 52T and 52R provided in the optical transmission path 52, the gain of the amplifier inserted in the optical transmission path 52, the NF of the amplifier, the type of the optical fibers 52T and 52R, etc. Note that the control unit 12 may calculate the transmission path information of the optical transmission path 52 in advance by a predetermined calculation based on the optical signal transmitted by the optical transmission path 52 and store it in an internal storage area, or may obtain it on demand from an external device at a specific timing, such as when laying down the network. The transmission path information of the optical transmission path 52 may also be obtained in advance by a method other than the predetermined calculation.

[0042] The control unit 12 stores information indicating available resources of the optical transmission path 52 in an internal storage area. Here, the information indicating available resources is, for example, information indicating wavelengths, wavelength bands, or optical transmission paths that are not used for communication when determining the availability of resources. The information indicating available resources is updated by the control unit 12 every time a communication path is established. The control unit 12 calculates transmission path characteristics (QoT (Quality of Transmission)) using, for example, an internal transmission design tool based on the connection information generated by the connection information generation unit 38 and the transmission path information of the optical transmission path 52 stored in the internal storage area. Here, for example, GNPy (Gaussian Noise model in Python) shown in Reference 2 below is used as the transmission design tool.

[0043] [Reference 2: Alessio Ferrari, et al, “The GNPy Open Source Library of Applications for Software Abstraction of WDM Data Transport in Open Optical Networks”, 2020 6th IEEE International Conference on Network Softwarization(NetSoft), DOI:10.1109 / NetSoft48620.2020.9165313, June 2020]

[0044] Here, the transmission path characteristics are values ​​calculated by a transmission design tool, such as OSNR, GSNR (Generalized Signal-to-Noise Ratio), Q value, BER, etc. However, here, the information calculated by the transmission design tool, such as OSNR, GSNR, Q value, BER, etc., is information on the OSNR, GSNR, Q value, BER, etc. of the entire optical transmission path including the optical transmission path 51 and the optical transmission path 52.

[0045] The control unit 12 selects configuration information specifying a transmission mode through a predetermined selection process based on the calculated transmission path characteristics, information indicating available resources of the optical transmission path 52 stored in an internal storage area, and desired bit rate information and specification information of the optical transceiver 21X included in the connection request data acquired from the digital signal processor 32. Here, the predetermined selection process is performed as follows. For example, an FEC type available for the optical transceiver 21X and the optical transceiver 21Y is selected based on the FEC type included in the specification information of the optical transceiver 21X. After selecting the FEC type, the control unit 12 compares an ONSR threshold determined for each modulation method included in the specification information of the optical transceiver 21X with the OSNR of the calculated transmission path characteristics, and selects a modulation method whose OSNR threshold is equal to or greater than the OSNR of the calculated transmission path characteristics. The control unit 12 selects configuration information by a process of selecting, from among multiple bit rate candidates for each of the selected modulation methods, a combination of a modulation method and a baud rate that enables transmission at a bit rate equal to or greater than the bit rate indicated in the desired bit rate information. The transmission mode is specified by the configuration information selected by the control unit 12. Here, the configuration information specifying the transmission mode includes, for example, the modulation method, baud rate, bit rate, and FEC (Forward Error Correction) type selected in the above-mentioned process, as well as information including output optical power and a signal band permitted for use. Note that information on FEC types available in the optical transceiver 21Y is acquired in advance by the control unit 12 and stored in an internal storage area, or is acquired on demand from the optical transceiver 21Y or an external device. In the above-mentioned predetermined selection process, a combination of a modulation method and a baud rate that enables transmission at a bit rate that is equal to or higher than the bit rate indicated in the desired bit rate information and that is closest to the bit rate indicated in the desired bit rate information may be selected from among multiple bit rate candidates for each of the selected modulation methods.

[0046] The control unit 12 generates transmission mode information including the selected configuration information and the connection source address information included in the connection request data. The control unit 12 outputs the generated transmission mode information to the digital signal processing unit 32. As shown in FIG. 1, the control unit 12 is connected to the control unit 20Y of the optical communication device 2Y, for example, via the connection line 3, and transmits the generated transmission mode information to the control unit 20Y of the optical communication device 2Y. The control unit 12 outputs a control signal (hereinafter referred to as a "switching instruction signal") that instructs the optical switch units 15T and 15R of the output port switching unit 14 to perform switching processing to switch the connection destination.

[0047] (Processing by the optical transmission system of the first embodiment) Fig. 3 is a flowchart showing the flow of processing by the optical transmission system 100. As shown in Fig. 2, the output port switching unit 14 of the connecting node apparatus 1 initially sets the connection destination of the optical transmission path 51 to the connection information processing unit 13 provided in the connecting node apparatus 1. More specifically, the optical switch unit 15T connects the optical fiber 51T to the optical receiver 34 via the IF unit 31, and the optical switch unit 15R connects the optical fiber 51R to the optical modulator 37 via the IF unit 31.

[0048] The control unit 20X of the optical communication device 2X generates a connection request instruction signal including address information of the optical transceiver 21Y and a desired bit rate to connect to the optical transceiver 21Y included in the optical communication device 2Y. The control unit 20X outputs the generated connection request instruction signal to a control unit 71X of the optical transceiver 21X. The control unit 71X receives the connection request instruction signal output by the control unit 20X and sets the address information of the optical transceiver 21Y included in the received connection request instruction signal as destination address information. The control unit 71X sets the address information of the optical transceiver 21X stored in an internal storage area as source address information. The control unit 71X generates connection request data including the destination address information, the source address information, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21X stored in an internal storage area.

[0049] The control unit 71X outputs an output optical power designation signal indicating a predetermined basic output optical power in the basic mode to the single-wavelength light source 25X. The single-wavelength light source 25X generates and outputs continuous light of a predetermined wavelength at the basic output optical power designated by the output optical power designation signal received from the control unit 71X. The control unit 71X outputs a modulation method designation signal indicating a predetermined basic modulation method in the basic mode to the optical modulator 26X. The optical modulator 26X starts optical modulation in accordance with the basic modulation method designated by the modulation method designation signal received from the control unit 71X.

[0050] The control unit 71X outputs the generated connection request data to the digital signal processing unit 23X. The digital signal processing unit 23X receives the connection request data output by the control unit 71X and generates a transmission data signal so that the received connection request data is included in an empty area in the overhead of a transmission frame. The digital signal processing unit 23X outputs the generated transmission data signal, which is an electrical signal, to the optical modulator 26X. The optical modulator 26X optically modulates the continuous light output by the single-wavelength light source 25X based on the transmission data signal including the connection request data output by the digital signal processing unit 23X. The optical modulator 26X transmits the optical signal generated by the optical modulation to the optical fiber 51T via the IF unit 22X. The optical fiber 51T transmits the optical signal to the optical switch unit 15T of the output port switching unit 14 of the connecting node device 1 (step S1).

[0051] The optical switch unit 15T receives an optical signal transmitted by the optical fiber 51T and outputs the received optical signal to the optical receiver 34 of the optical receiving unit 33 via the IF unit 31. The optical receiver 34 accepts the optical signal output by the optical switch unit 15T. The optical receiver 34 converts the accepted optical signal into an electrical signal to generate a received data signal. The optical receiver 34 outputs the received data signal to the digital signal processing unit 32. The digital signal processing unit 32 accepts the received data signal output by the optical receiver 34. The digital signal processing unit 32 reads connection request data included in the overhead area of ​​the accepted received data signal and outputs it to the connection information generation unit 38. The digital signal processing unit 32 obtains the BER of the optical transmission path 51 from the accepted received data signal and outputs it to the connection information generation unit 38. The connection information generation unit 38 accepts the connection request data and the BER output by the digital signal processing unit 32. The connection information generation unit 38 receives the connection request data and the BER output by the digital signal processing unit 32, and calculates transmission path information of the optical transmission path 51 based on the received data signal received by the digital signal processing unit 32 and output to the connection information generation unit 38. The connection information generation unit 38 generates connection information including the calculated transmission path information of the optical transmission path 51 and the BER of the optical transmission path 51. The connection information generation unit 38 outputs the received connection request data and the generated connection information to the control unit 12 (step S2).

[0052] The control unit 12 acquires the connection request data and connection information output by the connection information generation unit 38. The control unit 12 references a route information table stored in an internal storage area or a route information table acquired on demand, and detects the destination address information included in the acquired connection request data, in this case, identification information that identifies the optical transmission path 52 corresponding to the address information of the optical transceiver 21Y. The control unit 12 reads and acquires the transmission path information of the optical transmission path 52 corresponding to the detected identification information from an internal storage area, or acquires the transmission path information of the optical transmission path 52 on demand. The control unit 12 calculates transmission path characteristics based on the acquired transmission path information of the optical transmission path 52 and the acquired connection information (step S3).

[0053] The control unit 12 selects configuration information through a predetermined selection process based on the calculated transmission path characteristics, desired bit rate information included in the connection request data, and specification information of the optical transceiver 21X. The transmission mode is specified by the configuration information selected by the control unit 12. The control unit 12 generates transmission mode information including the selected configuration information and the source address information included in the connection request data (step S4).

[0054] The control unit 12 transmits the generated transmission mode information to the control unit 20Y of the optical communication device 2Y through the connection line 3 (step S5-1). The control unit 20Y of the optical communication device 2Y receives the transmission mode information transmitted by the control unit 12 of the connecting node device 1, and outputs the received transmission mode information to the control unit 71Y of the optical transceiver 21Y. The control unit 71Y captures the transmission mode information output by the control unit 20Y. The control unit 71Y outputs an output optical power designation signal indicating the output optical power indicated in the captured transmission mode information to the single-wavelength light source 25Y. As a result, the single-wavelength light source 25Y generates and outputs continuous light at the output optical power designated by the output optical power designation signal, i.e., the output optical power indicated in the transmission mode information.

[0055] The control unit 71Y outputs a modulation method designation signal indicating the modulation method indicated in the transmission mode information to the optical modulator 26Y. As a result, the optical modulator 26Y performs optical modulation using the modulation method designated by the modulation method designation signal received from the control unit 71Y, i.e., the modulation method indicated in the transmission mode information. The control unit 71Y outputs the transmission mode information to the digital signal processing unit 23Y. The digital signal processing unit 23Y acquires the transmission mode information output by the control unit 71Y and stores the modulation method, baud rate, bit rate, FEC type, and permitted signal band indicated in the acquired transmission mode information as setting parameters in an internal storage area. When generating a transmission data signal, the digital signal processing unit 23Y generates the transmission data signal based on the setting parameters stored in the internal storage area and outputs it to the optical modulator 26Y (step S6-1). The control unit 71Y may also store the modulation method, baud rate, bit rate, FEC type, and permitted signal band indicated in the transmission mode information as setting parameters in an internal storage area. In this case, the control unit 71Y outputs the setting parameters to the digital signal processing unit 23Y when the digital signal processing unit 23Y generates a transmission data signal.

[0056] The control unit 12 of the connecting node equipment 1 outputs an output optical power designation signal that designates the fundamental output optical power of the fundamental mode to the single-wavelength light source 36, and outputs a modulation method designation signal that designates the fundamental modulation method of the fundamental mode to the optical modulator 37. The control unit 12 outputs the generated transmission mode information to the digital signal processing unit 32. The digital signal processing unit 32 accepts the transmission mode information output by the control unit 12 and generates a transmission data signal so that the accepted transmission mode information is included in an empty area in the overhead of the transmission frame. The digital signal processing unit 32 outputs the generated transmission data signal, which is an electrical signal, to the optical modulator 37. Based on the transmission data signal output by the digital signal processing unit 32, the optical modulator 37 optically modulates the continuous light output by the single-wavelength light source 36 at the fundamental output optical power designated by the output optical power designation signal, in accordance with the fundamental modulation method of the fundamental mode designated by the modulation method designation signal.

[0057] The optical modulator 37 outputs an optical signal generated by optical modulation to the IF unit 31. The IF unit 31 receives the optical signal output by the optical modulator 37. The IF unit 31 outputs the received optical signal to the optical switch unit 15R. The optical switch unit 15R sends the optical signal output by the IF unit 31 to the optical fiber 51R. The optical fiber 51R transmits the optical signal sent by the optical switch unit 15R to the IF unit 22X of the optical communication device 2X (step S5-2).

[0058] The IF unit 22X of the optical communication device 2X receives the optical signal transmitted by the optical fiber 51R and outputs the received optical signal to the optical receiver 28X. The optical receiver 28X receives the optical signal output by the IF unit 22X and converts the received optical signal into an electrical signal to generate a received data signal. The optical receiver 28X outputs the received data signal to the digital signal processing unit 23X. The digital signal processing unit 23X takes in the received data signal output by the optical receiver 28X.

[0059] The digital signal processing unit 23X reads transmission mode information from the overhead area of ​​the received data signal and outputs the read transmission mode information to the control unit 71X. The control unit 71X reads the transmission mode information output by the digital signal processing unit 23X, and discards the read transmission mode information if the connection source address information included in the read transmission mode information does not match the address information assigned to the optical transceiver 21X stored in its internal storage area. In response to this, if the address information included in the read transmission mode information matches the address information assigned to the optical transceiver 21X, the control unit 71X outputs an output optical power designation signal indicating the output optical power indicated in the read transmission mode information to the single-wavelength light source 25X. As a result, the single-wavelength light source 25X generates and outputs continuous light at the output optical power designated by the output optical power designation signal, i.e., the output optical power indicated in the transmission mode information.

[0060] The control unit 71X outputs a modulation method designation signal indicating the modulation method indicated in the transmission mode information to the optical modulator 26X. As a result, the optical modulator 26X performs optical modulation using the modulation method designated by the modulation method designation signal received from the control unit 71X, i.e., the modulation method indicated in the transmission mode information. The digital signal processing unit 23X stores the modulation method, baud rate, bit rate, FEC type, and permitted signal bandwidth indicated in the read transmission mode information as setting parameters in an internal storage area. When generating a transmission data signal, the digital signal processing unit 23X generates the transmission data signal based on the setting parameters stored in the internal storage area and outputs the signal to the optical modulator 26X (step S6-2). The control unit 71X may also store the modulation method, baud rate, bit rate, FEC type, and permitted signal bandwidth indicated in the transmission mode information as setting parameters in an internal storage area. In this case, the control unit 71X outputs the setting parameters to the digital signal processing unit 23X when the digital signal processing unit 23X generates a transmission data signal.

[0061] The control unit 12 of the connecting node device 1 refers to the route information table and detects the connection source address information included in the generated transmission mode information, in this case, identification information identifying the optical transmission path 51 corresponding to the address information of the optical transceiver 21X. The control unit 12 performs a switching process to connect the optical transmission path 51 and the optical transmission path 52 based on the detected identification information identifying the optical transmission path 51 and the identification information identifying the optical transmission path 52 detected in the processing of step S3. The control unit 12 outputs a switching instruction signal to the optical switch unit 15T of the output port switching unit 14 to change the connection destination of the optical fiber 51T to the optical fiber 52T. The control unit 12 outputs a switching instruction signal to the optical switch unit 15R to change the connection destination of the optical fiber 51R to the optical fiber 52R.

[0062] When the optical switch unit 15T receives a switching instruction signal from the control unit 12, it connects the optical fiber 51T and the optical fiber 52T. When the optical switch unit 15R receives a switching instruction signal from the control unit 12, it connects the optical fiber 51R and the optical fiber 52R (step S7). As a result, as shown in FIG. 4, the optical fiber 51T and the optical fiber 52T are connected via the optical switch unit 15T, and the optical fiber 51R and the optical fiber 52R are connected via the optical switch unit 15R. As a result, the optical transceiver 21X of the optical communication device 2X and the optical transceiver 21Y of the optical communication device 2Y are connected via the optical transmission path 51 and the optical transmission path 52.

[0063] The processing order of steps S5-1 and S5-2 may be parallel, or steps S5-1 and S5-2 may be performed in that order, or steps S5-1 and S5-2 may be performed in reverse order.

[0064] In the configuration of the first embodiment described above, the connection information processing unit 13 acquires connection information including transmission path information, which is information related to the optical transmission path. The output port switching unit 14 connects the optical transmission path 51, which is a first optical transmission path, the optical transmission path 52, which is a second optical transmission path, and the connection information processing unit 13, and in an initial state, sets the connection destination of the optical transmission path 51 to the connection information processing unit 13. The control unit 12 transmits, via the optical transmission path 51, transmission mode information indicating a transmission mode identified based on the connection information of the optical transmission path 51 acquired by the connection information processing unit 13 from an optical signal transmitted by an optical transceiver 21X included in an optical communication device 2X connected to the optical transmission path 51, connection request data transmitted by the optical transceiver 21X in the optical signal, and the transmission path information of the optical transmission path 52. After the control unit 12 transmits the transmission mode information, for example, the output port switching unit 14 performs a switching process to switch the connection destination of the optical transmission path 51 from the connection information processing unit 13 to the optical transmission path 52. As a result, for example, when an optical communication device 2Y equipped with an optical transceiver 21Y is connected to the optical transmission path 52, when connecting the optical transceivers 21X and 21Y equipped in the optical communication devices 2X and 2Y via the multiple optical transmission paths 51 and 52, the connection can be made without manual intervention using an optical path of an optimal transmission mode. Therefore, it is possible to reduce the cost and time required to set up an optical path.

[0065] In the first embodiment described above, the control unit 12 of the connection node apparatus 1 calculates the end-to-end transmission path characteristics, i.e., the transmission path characteristics between one end of the optical transmission path 51 connected to the optical communication device 2X and one end of the optical transmission path 52 connected to the optical communication device 2Y, based on the connection information generated by the connection information processing unit 13 and the transmission path information of the optical transmission path 52. In contrast to this, the transmission path characteristics may be calculated as follows. The control unit 12 calculates the transmission path characteristics of the optical transmission path 51 based on the connection information generated by the connection information processing unit 13. The control unit 12 calculates the transmission path characteristics of the optical transmission path 52 based on the transmission path information of the optical transmission path 52. The control unit 12 may calculate approximate end-to-end transmission path characteristics based on the calculated transmission path characteristics of the optical transmission path 51 and the transmission path characteristics of the optical transmission path 52. For example, in the case where the transmission path characteristics include an OSNR and a GSNR, the control unit 12 calculates the OSNR and GSNR of the optical transmission path 51 and the OSNR and GSNR of the optical transmission path 52. The control unit 12 calculates an approximate end-to-end OSNR based on the calculated OSNR of the optical transmission path 51 and the OSNR of the optical transmission path 52. The control unit 12 calculates an approximate end-to-end GSNR based on the calculated GSNR of the optical transmission path 51 and the GSNR of the optical transmission path 52. Note that instead of calculating the transmission path characteristics of the optical transmission path 52 based on transmission path information of the optical transmission path 52, the control unit 12 may be configured as follows. The control unit 12 calculates the transmission path characteristics of the optical transmission path 52 in advance based on the transmission path information of the optical transmission path 52, and stores the calculated transmission path characteristics of the optical transmission path 52 in advance in an internal storage area. When the control unit 12 performs a process of calculating the transmission path characteristics of the optical transmission path 52, instead of performing the calculation process, the control unit 12 may obtain the transmission path characteristics of the optical transmission path 52 by reading the transmission path characteristics of the optical transmission path 52 from an internal memory area.

[0066] (Second embodiment) FIG. 5 is a block diagram showing the configuration of an optical transmission system 101 in the second embodiment. In the second embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and only the different components will be described below. The optical transmission system 101 includes a connection node apparatus 1a, an optical communication apparatus 2X, a plurality of optical communication apparatuses 2Y-1 to 2Y-n, an operation apparatus 4, an optical transmission path 51, optical transmission paths 52-1 to 52-n, a connection line 3, and connection lines 3-1 to 3-n connecting the operation apparatus 4 to the optical communication apparatuses 2Y-1 to 2Y-n, respectively. Here, n is an integer equal to or greater than 1. The optical transmission path 51 connects the optical communication apparatus 2X to the connection node apparatus 1a. The optical transmission paths 52-1 to 52-n connect each of the optical communication apparatuses 2Y-1 to 2Y-n to the connection node apparatus 1a. The connection line 3 connects the operation apparatus 4 to the connection node apparatus 1a.

[0067] Each of the optical communication devices 2Y-1 to 2Y-n has the same configuration as the optical communication device 2Y of the first embodiment, that is, the same configuration as the optical communication device 2X. Hereinafter, when indicating each functional unit provided in the optical communication devices 2Y-1 to 2Y-n, the "X" included in the reference numeral attached to each functional unit provided in the optical communication device 2X will be replaced with "Y-1" to "Yn", respectively. Like the optical transceiver 21X of the optical communication device 2X, each of the optical transceivers 21Y-1 to 21Y-n provided in the optical communication devices 2Y-1 to Yn is also assigned address information in advance that allows each to be identified.

[0068] Each of the optical transmission lines 52-1 to 52-n includes two optical fibers, similar to the optical transmission line 52 of the first embodiment, and the two optical fibers included in each line are indicated by the symbols "T" and "R". For example, in the case of the optical transmission line 52-1, the optical fibers are indicated as optical fibers 52T-1 and 52R-1. Each of the connection lines 3-1 to 3-n is a communication line similar to the connection line 3.

[0069] The connection node apparatus 1a includes an edge function unit 11a and an output port switching unit 14. The output port switching unit 14 is connected to the optical transmission path 51, the connection information processing unit 13 of the connection node apparatus 1a, and each of the optical transmission paths 52-1 to 52-n, and selects one of the connection information processing unit 13 and the optical transmission paths 52-1 to 52-n as a connection destination of the optical transmission path 51 to switch the connection destination.

[0070] The edge function unit 11a includes a connection information processing unit 13 and a control unit 12a. The control unit 12a stores in advance in an internal storage area an address path correspondence table in which each piece of address information of the optical transceivers 21X, 21Y-1 to 21Y-n included in each of the optical communication devices 2X, 2Y-1 to 2Y-n connected to the connection node device 1a is associated with identification information that specifies the optical transmission paths 51, 52-1 to 52-n to which the optical transceivers 21X, 21Y-1 to 21Y-n corresponding to each piece of address information are connected. Note that the control unit 12a may obtain the address path correspondence table on demand from an external device rather than storing the address path correspondence table in an internal storage area in advance.

[0071] The control unit 12a transmits the connection information output by the connection information generation unit 38 of the connection information processing unit 13 and the connection request data to the operation device 4 via the connection line 3. The control unit 12a outputs the transmission mode information received from the operation device 4 to the digital signal processing unit 32. The control unit 12a outputs a switching instruction signal to the output port switching unit 14 to switch the connection destination.

[0072] The operation device 4 includes a route detection unit 41 and a transmission path design unit 42. The route detection unit 41 stores in advance in an internal storage area a route information table that associates address information of the optical transceivers 21X, 21Y-1 to 21Y-n of the optical communication devices 2X, 2Y-1 to 2Y-n with identification information that specifies the optical transmission path corresponding to the address information. The route detection unit 41 may obtain the route information table on demand from an external device instead of storing the route information table in an internal storage area in advance.

[0073] For example, in the optical transmission system 101, in the route information table, each piece of address information of the optical transceivers 21X, 21Y-1 to 21Y-n included in each of the optical communication devices 2X, 2Y-1 to 2Y-n is associated with identification information that specifies the optical transmission paths 51, 52-1 to 52-n to which the optical transceivers 21X, 21Y-1 to 21Y-n corresponding to each address information are connected. The route detection unit 41 refers to the route information table and detects identification information that specifies one of the optical transmission paths 52-1 to 52-n that corresponds to the connection destination address information included in the connection request data transmitted by the control unit 12a of the connection node device 1a (where i is any integer from 1 to n).

[0074] The transmission path design unit 42 stores transmission path information for each of the optical transmission paths 52-1 to 52-n in an internal storage area in association with identification information that identifies each of the optical transmission paths 52-1 to 52-n. The transmission path design unit 42 may calculate the transmission path information for the optical transmission paths 52-1 to 52-n in advance by a predetermined calculation based on the optical signals transmitted by the optical transmission paths 52-1 to 52-n and store the calculated information in an internal storage area, or may obtain the information on demand from an external device at a specific time, such as when the network is installed. The transmission path information for the optical transmission paths 52-1 to 52-n may also be calculated in advance by a method other than the predetermined calculation.

[0075] The transmission path design unit 42 stores information indicating available resources of each of the optical transmission paths 52-1 to 52-n in an internal storage area. Here, the information indicating available resources is, for example, information indicating wavelengths, wavelength bands, or optical transmission paths that are not used for communication when determining the availability of resources. Note that the information indicating available resources is updated by the transmission path design unit 42 every time a communication path is established.

[0076] The transmission path design unit 42 calculates the transmission path characteristics using, for example, a transmission design tool such as GNPy provided inside, based on the connection information transmitted by the control unit 12a of the connection node device 1a and the transmission path information of the optical transmission path 52-i corresponding to the identification information identifying the optical transmission path 52-i detected by the path detection unit 41.

[0077] The transmission path design unit 42 selects configuration information through a predetermined selection process based on the calculated transmission path characteristics, information indicating available resources corresponding to the identification information identifying the optical transmission path 52-i detected by the path detection unit 41, and desired bit rate information and specification information of the optical transceiver 21X included in the connection request data transmitted by the control unit 12a of the connecting node apparatus 1a. The transmission mode is identified by the configuration information selected by the transmission path design unit 42. The transmission path design unit 42 generates transmission mode information including the selected configuration information and the connection source address information included in the connection request data. The transmission path design unit 42 transmits the generated transmission mode information and the identification information identifying the optical transmission path 52-i detected by the path detection unit 41 to the control unit 12a of the connecting node apparatus 1a via the connection line 3.

[0078] The transmission path design unit 42 stores in advance in an internal storage area a connection line table that associates address information of the optical transceivers 21Y-1 to 21Y-n provided in the optical communication devices 2Y-1 to 2Y-n with the connection lines 3-1 to 3-n to which the optical communication devices 2Y-1 to 2Y-n corresponding to the address information are connected. The transmission path design unit 42 refers to the connection line table stored in the internal storage area and transmits the generated transmission mode information to the control units 20Y-1 to 20Y-n of the optical communication devices 2Y-1 to 2Y-n through the connection lines 3-1 to 3-n that are connected to the optical communication devices 2Y-1 to 2Y-n that include the optical transceivers 21Y-1 to 21Y-n that correspond to the connection destination address information included in the connection request data.

[0079] (Processing by the optical transmission system of the second embodiment) 6 is a flowchart showing the flow of processing by the optical transmission system 101 of the second embodiment. Hereinafter, as an example, a process will be described in which the optical transceiver 21X included in the optical communication device 2X connects to the optical transceiver 21Y-i of the optical communication device 2Y-i as a connection destination. The processes of steps Sa1 and Sa2 in FIG. 6 are the same as steps S1 and S2 in the first embodiment. However, in step Sa1, it is assumed that the control unit 20X of the optical communication device 2X generates a connection request instruction signal including address information of the optical transceiver 21Y-i included in the optical communication device 2Y-i as address information of the connection destination, and that the optical communication device 2Y-i is connected to the optical transmission path 52-i and the connection line 3-i.

[0080] The control unit 12a receives the connection request data and connection information output by the connection information generating unit 38. The control unit 12a transmits the received connection request data and connection information to the operation device 4 via the connection line 3 (step Sa3).

[0081] The route detection unit 41 of the operation device 4 receives the connection request data sent by the control unit 12a. The route detection unit 41 refers to a route information table stored in an internal storage area or a route information table obtained on demand, and detects the destination address information included in the received connection request data, in this case, identification information that identifies the optical transmission path 52-i corresponding to the address information of the optical transceiver 21Y-i. The route detection unit 41 outputs the detected identification information that identifies the optical transmission path 52-i to the transmission path design unit 42 (step Sa4).

[0082] The transmission path design unit 42 receives the connection information and connection request data sent by the control unit 12a. The transmission path design unit 42 acquires identification information for identifying the optical transmission path 52-i output by the path detection unit 41. The transmission path design unit 42 reads and acquires the transmission path information of the optical transmission path 52-i corresponding to the acquired identification information for identifying the optical transmission path 52-i from an internal storage area, or acquires the transmission path information of the optical transmission path 52-i on demand. The transmission path design unit 42 calculates the transmission path characteristics based on the acquired transmission path information of the optical transmission path 52-i and the received connection information (step Sa5).

[0083] The transmission path design unit 42 selects configuration information through a predetermined selection process based on the calculated transmission path characteristics, the desired bit rate information included in the received connection request data, and the specification information of the optical transceiver 21X. The transmission mode is specified by the configuration information selected by the transmission path design unit 42. The transmission path design unit 42 generates transmission mode information including the selected configuration information and the source address information included in the connection request data (step Sa6).

[0084] The transmission path design unit 42 refers to the connection line table stored in an internal storage area and transmits the generated transmission mode information to the control unit 20Y-i of the optical communication device 2Y-i through the connection line 3-i connected to the optical communication device 2Y-i including the optical transceiver 21Y-i corresponding to the connection destination address information included in the connection request data (step Sa7-1). The control unit 20Y-i of the optical communication device 2Y-i receives the transmission mode information transmitted by the transmission path design unit 42 of the operation device 4 and outputs the received transmission mode information to the control unit 71Y-i of the optical transceiver 21X-i. Thereafter, the same process as step S6-1 in the first embodiment is performed by the functional units of the optical communication device 2Y-i corresponding to each of the functional units provided in the optical communication device 2Y in the first embodiment (step Sa8-1).

[0085] The transmission path design unit 42 transmits the generated transmission mode information and identification information for identifying the optical transmission path 52-i detected by the path detection unit 41 to the connection node apparatus 1a via the connection line 3 (step Sa7-2). The control unit 12a of the connection node apparatus 1a receives the transmission mode information and the identification information for identifying the optical transmission path 52-i transmitted by the transmission path design unit 42 of the operation apparatus 4. After the control unit 12a receives the transmission mode information and the identification information for identifying the optical transmission path 52-i, the control unit 12a, the connection information processing unit 13, and the output port switching unit 14 perform the same processing as step S5-2 in the first embodiment based on the received transmission mode information (step Sa8-2). Thereafter, the same processing as step S6-2 in the first embodiment is performed (step Sa9).

[0086] The control unit 12a of the connecting node device 1a detects identification information for identifying the optical transmission path 51 from an address path correspondence table stored in an internal storage area or from an address path correspondence table acquired on demand, based on the connection source address information included in the received transmission mode information (here, address information assigned to the optical transmitter / receiver 21X). The control unit 12a performs switching processing to connect the optical transmission path 51 and the optical transmission path 52-i, based on the detected identification information for identifying the optical transmission path 51 and the received identification information for identifying the optical transmission path 52-i. The control unit 12a outputs a switching instruction signal to the optical switch unit 15T of the output port switching unit 14, specifying the optical fiber 52T-i as the connection destination of the optical fiber 51T. The control unit 12a outputs a switching instruction signal to the optical switch unit 15R, specifying the optical fiber 52R-i as the connection destination of the optical fiber 51R.

[0087] Upon receiving a switching instruction signal from the control unit 12a, the optical switch unit 15T connects the optical fiber 51T to the optical fiber 52T-i. Upon receiving a switching instruction signal from the control unit 12a, the optical switch unit 15R connects the optical fiber 51R to the optical fiber 52R-i (step Sa10). As a result, the optical fiber 51T is connected to the optical fiber 52T-i via the optical switch unit 15T, and the optical fiber 51R is connected to the optical fiber 52R-i via the optical switch unit 15R. As a result, the optical communication device 2X and the optical communication device 2Y-i are connected via the optical transmission path 51 and the optical transmission path 52-i.

[0088] The processing order of steps Sa7-1 and Sa7-2 may be parallel, or steps Sa7-1 and Sa7-2 may be performed in that order, or steps Sa7-1 and Sa7-2 may be performed in reverse order.

[0089] In the configuration of the second embodiment, optical communication device 2X, which is a first optical communication device, is connected to connecting node device 1a via optical transmission path 51, which is a first optical transmission path. Optical communication devices 2Y-1 to 2Y-n, which are second optical communication devices, are connected to connecting node device 1a via optical transmission paths 52-1 to 52-n, which are second optical transmission paths. Operation device 4 is connected to connecting node device 1a and each of optical communication devices 2Y-1 to 2Y-n. The operation device 4 reads and acquires the transmission path information of the optical transmission path 52-i stored in advance in an internal storage area from the internal storage area, or acquires the transmission path information of the optical transmission path 52-i on demand, identifies a transmission mode based on the acquired transmission path information of the optical transmission path 52-i, the connection information of the optical transmission path 51 acquired by the connection information processing unit 13 of the connecting node device 1a from the optical signal transmitted by the optical transmitter / receiver 21X provided in the optical communication device 2X, and the connection request data included in the optical signal and transmitted by the optical transmitter / receiver 21X provided in the optical communication device 2X, and transmits transmission mode information indicating the identified transmission mode to the control unit 12a of the connecting node device 1a and the optical transmitter / receiver 21Y-i provided in the optical communication device 2Y-i. The optical transceiver 21X included in the optical communication device 2X receives transmission mode information that the control unit 12a of the connecting node device 1a receives from the operation device 4 and sends to the optical transmission path 51, and transmits and receives optical signals through the optical transmission path 51 in the transmission mode indicated by the received transmission mode information. The optical transceiver 21Y-i included in the optical communication device 2Y-i transmits and receives optical signals through the optical transmission path 52-i in the transmission mode indicated by the transmission mode information received from the operation device 4. After the control unit 12a transmits the transmission mode information to the optical communication device 2X through the optical transmission path 51, the output port switching unit 14 of the connecting node device 1a connects the optical transceiver 21X included in the optical communication device 2X and the optical transceiver 21Y-i included in the optical communication device 2Y-i via the optical transmission path 51 and the optical transmission path 52 by switching processing. As a result, when connecting the optical transceivers 21X and 21Y-i of the optical communication devices 2X and 2Y-i via the multiple optical transmission paths 51 and 52-i, the connection can be made without manual intervention using an optical path in an optimal transmission mode, thereby reducing the cost and time required to set up the optical path.

[0090] In the optical transmission system 101 of the second embodiment described above, instead of including the optical communication devices 2Y-1 to 2Y-n, a single optical communication device 2cY including a plurality of optical transceivers 21Y-1 to 21Y-n and a single control unit 20aY may be provided, as in the optical transmission system 101a shown in Fig. 7, in which a plurality of optical transmission paths 52-1 to 52-n are connected to each of the optical transceivers 21Y-1 to 21Y-n. In the optical transmission system 101 shown in Fig. 5, the transmission path design unit 42 refers to the connection line table stored in an internal storage area and transmits transmission mode information to the control units 20Y-1 to 20Y-n of the optical communication devices 2Y-1 to 2Y-n through the connection lines 3-1 to 3-n corresponding to the connection destination address information included in the transmission mode information. 7, the transmission path design unit 42a included in the operation device 4a adds the connection destination address information included in the connection request data to the generated transmission mode information, and transmits it to the control unit 20aY of the optical communication device 2cY through the connection line 3-1. Therefore, the transmission path design unit 42a does not need to store a connection line table in advance in an internal storage area.

[0091] The control unit 20aY has the same configuration as each of the control units 20Y-1 to 20Y-n, except for the following configuration. When each of the control units 20Y-1 to 20Y-n receives transmission mode information transmitted by the transmission path design unit 42a, it outputs the received transmission mode information to the optical transceivers 21Y-1 to 21Y-n connected to it. In response to this, when the control unit 20aY receives transmission mode information transmitted by the transmission path design unit 42a via the connection line 3-1, it outputs the transmission mode information to one of the optical transceivers 21Y-1 to 21Y-n that corresponds to the destination address information assigned to the received transmission mode information.

[0092] By having the above configuration, in the optical transmission system 101a, similarly to the optical transmission system 101, the destination address information of the connection request data is set to the address information of the optical transceiver 21Y-i requesting connection, thereby connecting to the optical transceiver 21Y-i corresponding to the destination address information via the optical transmission paths 51, 52-i, and it becomes possible to transmit and receive optical signals in the same transmission mode between the optical transceiver 21X and the optical transceiver 21Y-i.

[0093] (Third embodiment) FIG. 8 is a block diagram showing the configuration of an optical transmission system 102 according to the third embodiment. In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and only the different components will be described below. The optical transmission system 102 includes a connection node apparatus 1b, an optical communication apparatus 2aX, a plurality of optical communication apparatuses 2bY-1 to 2bY-n, an operation apparatus 4b, an optical transmission path 51, optical transmission paths 52-1 to 52-n, a connection line 3, and connection lines 3-1 to 3-n. The optical communication apparatus 2aX is, for example, a communication apparatus used by a user, and the optical communication apparatuses 2bY-1 to 2bY-n are, for example, optical transmission apparatuses owned by a telecommunications carrier, i.e., node apparatuses in a communication network, or white-box transponders owned by a telecommunications carrier or a data center operator. The optical transmission path 51 connects the optical communication apparatus 2aX and the connection node apparatus 1b. Optical transmission paths 52-1 to 52-n connect each of the optical communication devices 2bY-1 to 2bY-n and the connection node device 1b. A connection line 3 connects the operation device 4b and the connection node device 1b. Connection lines 3-1 to 3-n connect the operation device 4b and each of the optical communication devices 2bY-1 to 2bY-n.

[0094] The internal configurations of the connection node apparatus 1b, the optical communication apparatus 2aX, the optical communication apparatuses 2bY-1 to 2bY-n, and the operation apparatus 4b will be described with reference to Fig. 8 and Fig. 9. Among the connection lines shown in Fig. 8 and Fig. 9, the thick dotted lines indicate wavelength paths of the fundamental wavelength, and the thick dashed lines indicate wavelength paths of wavelengths other than the fundamental wavelength. The thick dotted arrows indicate optical data signals transmitted through the wavelength paths of the fundamental wavelength.

[0095] 8, the optical communication device 2aX includes a plurality of optical transmitters and receivers 21aX-1 to 21aX-m, a wavelength multiplexing / demultiplexing unit 6aX, a control unit 20aX, and a transmission control unit 29X, where m is an integer equal to or greater than 1, and may be the same value as n or may be a different value from n.

[0096] The control unit 20aX is connected to each of the optical transceivers 21aX-1 to 21aX-m, and controls each of the optical transceivers 21aX-1 to 21aX-m and inputs and outputs information to and from the optical transceivers 21aX-1 to 21aX-m. The control unit 20aX generates a connection request instruction signal when starting a connection to one of the optical transceivers 21aY-1 to 20aY-n provided in each of the optical communication devices 2bY-1 to 2bY-n, that is, the optical transceiver 21aY-i.

[0097] 9, the optical transceiver 21aX-1 includes an IF unit 22X-1, an optical transmitter 24aX-1, an optical receiver 27X-1, a digital signal processor 23aX-1, and a controller 71aX-1. The IF unit 22X-1 connects the optical transmitter 24aX-1 to the optical fiber 51T via a wavelength multiplexer 8aX included in the wavelength multiplexer / demultiplexer 6aX. The IF unit 22X-1 connects the optical receiver 27X-1 to the optical fiber 51R via a wavelength demultiplexer 7aX included in the wavelength multiplexer / demultiplexer 6aX.

[0098] For example, when starting a connection to one of the optical transceivers 21aY-1 to 21aY-n included in the optical communication devices 2bY-1 to 2bY-n, the control unit 71aX-1 receives a connection request instruction signal from the control unit 20aX and generates connection request data of an electrical signal requesting a connection. The specification information of the optical transceiver 21aX-1 included in the connection request data in the third embodiment includes, for example, a modulation method, an FEC type, and a baud rate available for the optical transmitter 24aX-1, as well as information that the tunable light source 25aX-1 included in the optical transmitter 24aX-1 is a type that outputs a variable wavelength, and information indicating the range of wavelengths that can be generated by the tunable light source 25aX-1, i.e., the wavelength band of the tunable light source 25aX-1.

[0099] The optical transceivers 21aX-1 to 21aX-m included in the optical communication device 2aX and the optical transceivers 21aY-1 to 21aY-n included in the optical communication devices 2bY-1 to 2bY-n are each assigned with address information that allows them to be identified. The control unit 20aX stores a desired bit rate and address information of the connection destination in an internal storage area in advance. The control unit 71aX-1 of the optical transceiver 21aX-1 stores the address information assigned to the optical transceiver 21aX-1 included in itself in an internal storage area in advance. For example, when the optical transceiver 21aX-1 is installed in the optical communication device 2aX, the control unit 71aX-1 acquires specification information of the optical transceiver 21aX-1 from the optical transmitter 24aX-1 and the digital signal processing unit 23aX-1 and stores the information in an internal storage area. The control unit 20aX may acquire the address information of the connection destination designated by the user of the optical communication device 2aX, or may acquire the address information of the connection destination from the connection node device 1b, for example, instead of storing the desired bit rate in an internal storage area in advance. The control unit 20aX may acquire the data of the bit rate designated in advance by the user in response to an input operation by the user, instead of storing the desired bit rate in an internal storage area in advance.

[0100] For example, when the optical transceiver 21aX-1 requests connection to the optical transceiver 21aY-i of the optical communication device 2aY-i, the control unit 20aX generates a connection request instruction signal including address information of the optical transceiver 21aY-i and a desired bit rate, and outputs the signal to the control unit 71aX-1 of the optical transceiver 21aX-1. The control unit 71aX-1 reads the address information of the optical transceiver 21aY-i included in the connection request instruction signal received from the control unit 20aX and sets it as destination address information, and reads the address information of the optical transceiver 21aX-1 stored in an internal memory area and sets it as source address information. The control unit 71aX-1 generates connection request data including the destination address information, source address information, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21aX-1 stored in an internal memory area. The control unit 71aX-1 outputs the generated connection request data to the digital signal processing unit 23aX-1.

[0101] The control unit 71aX-1 collects optical input information, such as that shown in Patent Document 2, including information such as the number of wavelengths multiplexed, OutPut-Power, and TxOSNR of the optical transmitting unit 24aX-1, which is collected in advance, from information related to the optical transmitting and receiving unit 21aX-1, such as the type and number of transceivers included in the optical transmitting and receiving unit 21aX-1. The control unit 71aX-1 outputs the collected optical input information to the digital signal processing unit 23aX-1.

[0102] The optical transmitter 24aX-1 includes a wavelength-tunable light source 25aX-1 and an optical modulator 26X-1. The wavelength-tunable light source 25aX-1 generates continuous light having an optical power specified by an output optical power specification signal output by the control unit 71aX-1 and a wavelength specified by an electrical control signal (hereinafter referred to as a "wavelength specification signal") that specifies the wavelength output by the control unit 71aX-1. The wavelength-tunable light source 25aX-1 outputs the generated continuous light to the optical modulator 26X-1.

[0103] The digital signal processing unit 23aX-1 has the following configuration in addition to the configuration of the digital signal processing unit 23X of the first embodiment: When transmitting optical input information output by the control unit 71aX-1 as a transmission data signal, the digital signal processing unit 23aX-1 generates a transmission data signal so that the optical input information is included in a communication channel of a transmission frame.

[0104] The optical modulator 26X-1 has the same configuration as the optical modulator 26X of the first embodiment. The optical receiving unit 27X-1 has the same configuration as the optical receiving unit 27X of the first embodiment. Each of the optical transmitting and receiving units 21aX-2 to 21aX-m other than the optical transmitting and receiving unit 21aX-1 has the same configuration as the optical transmitting and receiving unit 21aX-1. Hereinafter, when referring to the functional units included in each of the optical transmitting and receiving units 21aX-2 to 21aX-m, the suffix "-1" of the reference numeral of each functional unit included in the optical transmitting and receiving unit 21aX-1 will be replaced with the suffix "-2" to "-m" of the corresponding functional unit. For example, the optical transmitting and receiving unit 21aX-2 will be referred to as the digital signal processing unit 23aX-2.

[0105] The transmission control unit 29X is connected to each of the optical transceivers 21aX-1 to 21aX-m and outputs a timing signal indicating the timing at which to transmit connection request data to the optical transceivers 21aX-1 to 21aX-m. The optical transceivers 21aX-1 to 21aX-m all transmit the connection request data through the wavelength path 61-B of the fundamental wavelength. Therefore, unless the optical transceivers 21aX-1 to 21aX-m transmit the connection request data at different times, there is a risk of collision of the connection request data. To avoid such collision, the transmission control unit 29X outputs a timing signal to the optical transceivers 21aX-1 to 21aX-m, which enables the optical transceivers 21aX-1 to 21aX-m to transmit the connection request data at different times. Note that the procedure by which the connection node apparatus 1b connects to the multiple optical transceivers 21aX-1 to 21aX-m using the fundamental wavelength is based on the techniques disclosed in, for example, Patent Document 1 and Patent Document 2.

[0106] The optical communication device 2bY-1 includes an optical transceiver 21aY-1 and a control unit 20Y-1. The optical transceiver 21aY-1 has the same configuration as the optical transceiver 21aX-1. Hereinafter, when referring to functional units included in the optical transceiver 21aY-1, the suffix "X-1" in the reference numeral of each functional unit included in the optical transceiver 21aX-1 will be replaced with "Y-1". The optical communication devices 2bY-2 to 2bY-n other than the optical communication device 2bY-1 have the same configuration as the optical communication device 2bY-1, and when referring to each functional unit included in the optical communication devices 2Y-2 to 2Y-n, the suffix "-1" in the reference numeral of each functional unit included in the optical communication device 2bY-1 will be replaced with "-2" to "-n", respectively.

[0107] The connection node apparatus 1b includes an edge function unit 11b and an output port switching unit 14a. The output port switching unit 14a includes optical switches 15aT and 15aR, such as a WSS (Wavelength Selective Switch) or a Fiber Patch Panel, a wavelength demultiplexer 7a, and a wavelength multiplexer 8a. The wavelength demultiplexer 7a connects the optical fiber 51T to the optical switch unit 15aT, demultiplexes the optical signal wavelength-multiplexed in the optical fiber 51T, and outputs each of the demultiplexed optical signals to the optical switch unit 15aT. The wavelength multiplexer 8a connects the optical fiber 51R to the optical switch unit 15aR, multiplexes and wavelength-multiplexes optical signals of different wavelengths output by the optical switch unit 15aR, and transmits the wavelength-multiplexed optical signal to the optical fiber 51R.

[0108] The connection node equipment 1b may include a wavelength demultiplexing unit 7a and a wavelength multiplexing unit 8a outside the output port switching unit 14a, with the wavelength demultiplexing unit 7a connected to the optical fiber 51T and the optical switch unit 15aT, and the wavelength multiplexing unit 8a connected to the optical fiber 51R and the optical switch unit 15aR. A wavelength multiplexing / demultiplexing device 6 as a standalone device including the wavelength demultiplexing unit 7a and the wavelength multiplexing unit 8a may be provided outside the connection node equipment 1b, with the wavelength demultiplexing unit 7a of the wavelength multiplexing / demultiplexing device 6 connected to the optical fiber 51T and the optical switch unit 15aT, and the wavelength multiplexing unit 8a of the wavelength multiplexing / demultiplexing device 6 connected to the optical fiber 51R and the optical switch unit 15aR.

[0109] The optical switch unit 15aT connects the optical fiber 51T, the edge function unit 11b, and the optical fibers 52T-1 to 52T-n included in the optical transmission paths 52-1 to 52-n. The optical switch unit 15aT connects the wavelength path 61T-B of the fundamental wavelength, among the wavelength paths of each wavelength demultiplexed by the wavelength demultiplexer 7a, to the optical receiving unit 33 of the edge function unit 11b via the IF unit 31. Upon receiving a switching instruction signal, the optical switch unit 15aT performs switching processing to connect any one of the wavelength paths other than the wavelength path 61T-B of the fundamental wavelength included in the optical fiber 51T to any one of the wavelength paths included in the optical fibers 52T-1 to 52T-n.

[0110] The optical switch unit 15aR connects to the wavelength multiplexing unit 8a, the edge function unit 11b, and the optical fibers 52R-1 to 52R-n included in the optical transmission paths 52-1 to 52-n. The optical switch unit 15aR connects the wavelength path 61R-B of the fundamental wavelength, among the wavelength paths included in the optical fiber 51R connected via the wavelength multiplexing unit 8a, to the optical transmitter 35 of the edge function unit 11b via the IF unit 31. Upon receiving a switching instruction signal, the optical switch unit 15aR performs switching processing to connect any one of the wavelength paths other than the wavelength path 61R-B of the fundamental wavelength included in the optical fiber 51R to any one of the wavelength paths included in the optical fibers 52R-1 to 52R-n.

[0111] The edge function unit 11b includes a control unit 12b and a connection information processing unit 13a. The connection information processing unit 13a includes an IF unit 31, a digital signal processing unit 32a, an optical receiving unit 33, an optical transmitting unit 35, and a connection information generation unit 38a. The digital signal processing unit 32a includes the following components in addition to the components included in the digital signal processing unit 32 of the first and second embodiments. When optical input information is included in a received data signal output by the optical receiver 34, the digital signal processing unit 32a reads and acquires the optical input information from the received data signal. The digital signal processing unit 32a outputs the acquired optical input information to the connection information generation unit 38a.

[0112] The connection information generator 38a calculates transmission path information of the optical transmission path 51 based on the received data signal output by the digital signal processor 32a of the connection information processor 13a. The connection information generator 38a generates connection information including the calculated transmission path information of the optical transmission path 51, the BER of the optical transmission path 51 output by the digital signal processor 32a, and optical input information. The connection information generator 38a outputs the generated connection information and the connection request data output by the digital signal processor 32a to the controller 12b.

[0113] The control unit 12b stores in advance in an internal storage area an address path correspondence table in which identification information specifying the optical transmission paths 51, 52-1 to 52-n connected to the optical transmission / reception units 21aX-1 to 21aX-m, 21aY-1 to 21aY-n corresponding to each address information is associated with each piece of address information of the optical transmission / reception units 21aX-1 to 21aX-m, 21aY-1 to 21aY-n included in each of the optical communication devices 2aX, 2bY-1 to 2bY-n connected to the connection node device 1b. Note that the control unit 12b may acquire the address path correspondence table on demand from an external device instead of storing the acquired address path correspondence table in an internal storage area in advance.

[0114] The control unit 12b transmits the connection request data and connection information output by the connection information generation unit 38a to the operation device 4b via the connection line 3. The control unit 12b outputs the transmission mode information received from the operation device 4b to the digital signal processing unit 32a. The control unit 12b outputs a switching instruction signal to the output port switching unit 14a.

[0115] The operation device 4b includes a route detection unit 41 and a transmission path design unit 42b. The transmission path design unit 42b has the same configuration as the transmission path design unit 42 of the second embodiment, except for the configuration described below. Like the transmission path design unit 42 of the second embodiment, the transmission path design unit 42b selects configuration information through a predetermined selection process based on the calculated transmission path characteristics, information indicating available resources of the optical transmission paths 52-1 to 52-n corresponding to the connection destination address information included in the connection request data, and desired bit rate information and specification information of the optical transceivers 21aX-1 to 21aX-m included in the connection request data acquired by the digital signal processing unit 32a. However, the configuration information selected by the transmission path design unit 42b includes information on the center wavelength in addition to information such as the output optical power, modulation method, baud rate, bit rate, FEC (Forward Error Correction) type, and signal band allowed to be used, which are selected by the transmission path design unit 42 of the second embodiment, and may further include information on the number of WDM wavelengths.

[0116] The wavelength multiplexing / demultiplexing unit 6aX includes a wavelength multiplexing unit 8aX and a wavelength demultiplexing unit 7aX. The wavelength multiplexing unit 8aX multiplexes and wavelength-multiplexes optical signals of different wavelengths output by the IF units 22X-1 to 22X-m included in the optical transmitters and receivers 21aX-1 to 21aX-m, and transmits the wavelength-multiplexed optical signal to the optical fiber 51T. The wavelength demultiplexing unit 7aX demultiplexes the wavelength-multiplexed optical signal transmitted by the optical fiber 51R according to wavelength. The wavelength demultiplexing unit 7aX outputs each of the demultiplexed optical signals to the IF units 22X-1 to 22X-m corresponding to each wavelength. However, if there are multiple optical transmitters and receivers 21aX-1 to 21aX-m connected in the fundamental mode, the wavelength demultiplexing unit 7aX outputs optical signals to all of the optical transmitters and receivers 21aX-1 to 21aX-m connected in the fundamental mode.

[0117] (Processing by the optical transmission system of the third embodiment) Fig. 10 is a flowchart showing the flow of processing by the optical transmission system 102. As shown in Fig. 9, the optical switch unit 15aT of the output port changeover unit 14a of the connecting node equipment 1b connects the wavelength path 61T-B of the fundamental wavelength of the optical fiber 51T to the optical receiving unit 33 via the IF unit 31 of the connecting node equipment 1b. The optical switch unit 15aR connects the wavelength path 61R-B of the fundamental wavelength of the optical fiber 51R to the optical modulator 37 via the IF unit 31 of the connecting node equipment 1b.

[0118] The following describes, as an example, a process of connecting the optical transceiver 21aX-1 included in the optical communication device 2aX as the connection source and the optical transceiver 21aY-i included in the optical communication device 2bY-i as the connection destination. The control unit 20aX of the optical transceiver 21aX-1 generates a connection request instruction signal including address information of the optical transceiver 21aY-i and a desired bit rate to connect to the optical transceiver 21aY-i included in the optical communication device 2bY-i. The control unit 20aX outputs the generated connection request instruction signal to the control unit 71aX-1 of the optical transceiver 21aX-1. After receiving the connection request signal output by the control unit 20aX, the control unit 71aX-1 receives a timing signal output by the transmission control unit 29X and starts processing at the timing indicated by the received timing signal (step Sb1).

[0119] The control unit 71aX-1 sets the address information of the optical transceiver 21aY-i included in the captured connection request signal as the destination address. The control unit 71aX-1 sets the address information of the optical transceiver 21aX-1 stored in an internal storage area as source address information. The control unit 71aX-1 generates connection request data including the destination address information, the source address information, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21aX-1 stored in an internal storage area.

[0120] The control unit 71aX-1 outputs an output optical power designation signal indicating a predetermined fundamental output optical power in the fundamental mode to the wavelength-tunable light source 25aX-1. The control unit 71aX-1 outputs a wavelength designation signal of a predetermined fundamental wavelength in the fundamental mode to the wavelength-tunable light source 25aX-1. The control unit 71aX-1 outputs a modulation method designation signal of the predetermined fundamental mode to the optical modulator 26X-1. The optical modulator 26X-1 starts optical modulation in accordance with the fundamental modulation method designated by the modulation method designation signal.

[0121] The tunable light source 25aX-1 generates continuous light having a fundamental wavelength specified by the wavelength specification signal and a fundamental output optical power specified by the output optical power specification signal. The tunable light source 25aX-1 outputs the generated continuous light to the optical modulator 26X-1. The control unit 71aX-1 outputs the generated connection request data and the collected optical input information to the digital signal processing unit 23aX-1. The digital signal processing unit 23aX-1 receives the connection request data and the optical input information output by the control unit 71aX-1 and generates a transmission data signal so that the received connection request data is included in the free space in the overhead of the transmission frame and so that the optical input information is included in the communication channel of the transmission frame. The digital signal processing unit 23aX-1 outputs the generated transmission data signal, which is an electrical signal, to the optical modulator 26X-1.

[0122] The optical modulator 26X-1 optically modulates the continuous light output from the tunable wavelength light source 25aX-1 based on the transmission data signal output from the digital signal processing unit 23aX-1. The optical modulator 26X-1 outputs the optical signal of the fundamental wavelength generated by the optical modulation to the wavelength multiplexing unit 8aX of the wavelength multiplexing / demultiplexing unit 6aX via the IF unit 22X-1. The wavelength multiplexing unit 8aX multiplexes the optical signal of the fundamental wavelength output from the IF unit 22X-1 with optical signals of other wavelengths to perform wavelength multiplexing, and transmits the wavelength-multiplexed optical signal to the optical fiber 51T. The wavelength path 61T-B of the fundamental wavelength of the optical fiber 51T transmits the optical signal of the fundamental wavelength to the wavelength demultiplexing unit 7a of the connecting node equipment 1b (step Sb2).

[0123] The wavelength demultiplexing unit 7a demultiplexes the optical signal transmitted by the optical fiber 51T into wavelengths and outputs each of the demultiplexed optical signals to the optical switch unit 15aT. The optical switch unit 15aT receives the optical signal of the fundamental wavelength transmitted by the wavelength path 61T-B of the fundamental wavelength of the optical fiber 51T and outputs the received optical signal to the optical receiver 34 of the optical receiving unit 33 via the IF unit 31. The optical receiver 34 accepts the optical signal output by the optical switch unit 15aT. The optical receiver 34 converts the accepted optical signal into an electrical signal to generate a received data signal. The optical receiver 34 outputs the received data signal to the digital signal processing unit 32a.

[0124] The digital signal processing unit 32a receives the received data signal output by the optical receiver 34. The digital signal processing unit 32a reads and acquires connection request data included in the overhead area of ​​the received data signal. The digital signal processing unit 32a reads and acquires optical input information included in the communication channel of the received data signal. The digital signal processing unit 32a acquires the BER of the optical transmission path 51 from the received data signal. The digital signal processing unit 32a outputs the acquired connection request data, optical input information, and BER of the optical transmission path 51 to the connection information generation unit 38a.

[0125] The connection information generation unit 38a receives the connection request data, optical input information, and the BER of the optical transmission path 51 output by the digital signal processing unit 32a. Upon receiving the connection request data, optical input information, and the BER of the optical transmission path 51, the connection information generation unit 38a calculates and acquires transmission path information of the optical transmission path 51 by a predetermined calculation based on the received data signal received and output by the digital signal processing unit 32a. The connection information generation unit 38a generates connection information including the calculated transmission path information of the optical transmission path 51, the received optical input information, and the received BER of the optical transmission path 51. The connection information generation unit 38a outputs the received connection request data and the generated connection information to the control unit 12b (step Sb3).

[0126] The control unit 12b receives the connection request data and connection information output by the connection information generating unit 38a, and transmits the received connection request data and connection information to the operation device 4b via the connection line 3 (step Sb4).

[0127] The route detection unit 41 of the operation device 4b receives the connection request data sent by the control unit 12b. The route detection unit 41 refers to a route information table stored in an internal storage area or a route information table obtained on demand, and detects the destination address information included in the received connection request data, in this case, identification information that identifies the optical transmission path 52-i corresponding to the address information of the optical transceiver 21aY-i. The route detection unit 41 outputs the detected identification information that identifies the optical transmission path 52-i to the transmission path design unit 42b (step Sb5).

[0128] The transmission path design unit 42b receives the connection information and connection request data sent by the control unit 12b. The transmission path design unit 42b acquires identification information that identifies the optical transmission path 52-i output by the path detection unit 41. The transmission path design unit 42b reads and acquires the transmission path information of the optical transmission path 52-i that corresponds to the acquired identification information that identifies the optical transmission path 52-i from an internal storage area, or acquires the transmission path information of the optical transmission path 52-i on demand. The transmission path design unit 42b calculates the transmission path characteristics based on the acquired transmission path information of the optical transmission path 52-i and the received connection information (step Sb6).

[0129] The transmission path design unit 42b selects configuration information through a predetermined selection process based on the calculated transmission path characteristics, the desired bit rate information included in the received connection request data, and the specification information of the optical transceiver 21aX-1. The transmission mode is identified by the configuration information selected by the transmission path design unit 42b. The transmission path design unit 42b generates transmission mode information including the selected configuration information and the source address information included in the connection request data (step Sb7).

[0130] The transmission path design unit 42b refers to the connection line table stored in its internal memory area and transmits the generated transmission mode information to the control unit 20Y-i of the optical communication device 2bY-i through the connection line 3-i connected to the optical communication device 2bY-i equipped with the optical transceiver 21aY-i corresponding to the destination address information included in the connection request data (step Sb8-1).

[0131] The control unit 20Y-i of the optical communication device 2bY-i receives the transmission mode information transmitted by the transmission path design unit 42b and outputs the received transmission mode information to the control unit 71aY-i of the optical transceiver 21aY-i. The control unit 71aY-i acquires the transmission mode information output by the control unit 20Y-i. The control unit 71aY-i outputs an output optical power designation signal indicating the output optical power indicated in the acquired transmission mode information to the wavelength-tunable light source 25aY-i and a wavelength designation signal indicating the center wavelength specified in the acquired transmission mode information to the wavelength-tunable light source 25aY-i. As a result, the wavelength-tunable light source 25aY-i generates and outputs continuous light having the output optical power designated by the output optical power designation signal, i.e., continuous light having the output optical power and center wavelength indicated in the transmission mode information, at the output optical power designated by the output optical power designation signal. The wavelength-tunable light source 25aY-i outputs the generated continuous light to the optical modulator 26Y-i.

[0132] The control unit 71aY-i outputs a modulation method designation signal indicating the modulation method specified in the acquired transmission mode information to the optical modulator 26Y-i. As a result, the optical modulator 26Y-i performs optical modulation using the modulation method specified by the modulation method designation signal received from the control unit 71aY-i, i.e., the modulation method indicated in the transmission mode information. The control unit 71aY-i outputs the transmission mode information to the digital signal processing unit 23aY-i. The digital signal processing unit 23aY-i acquires the transmission mode information output by the control unit 71aY-i and stores the modulation method, baud rate, bit rate, FEC type, permitted signal bandwidth, and other information indicated in the acquired transmission mode information as setting parameters in an internal storage area. When generating a transmission data signal, the digital signal processing unit 23aY-i generates the transmission data signal based on the setting parameters stored in the internal storage area and outputs the signal to the optical modulator 26Y-i (step Sb9-1). The control unit 71aY-i may store the modulation method, baud rate, bit rate, FEC type, signal band permitted to be used, etc., indicated in the transmission mode information as setting parameters in an internal storage area. In this case, the control unit 71aY-i outputs the setting parameters to the digital signal processing unit 23aY-i when the digital signal processing unit 23aY-i generates a transmission data signal.

[0133] The transmission path design unit 42b of the operation device 4b transmits transmission mode information indicating the identified transmission mode and identification information identifying the optical transmission path 52-i detected by the path detection unit 41 to the connection node device 1b via the connection line 3 (step Sb8-2).

[0134] The control unit 12b of the connecting node equipment 1b receives the transmission mode information and identification information for specifying the optical transmission line 52-i transmitted by the transmission line designing unit 42b. The control unit 12b outputs an output optical power designation signal for designating the fundamental output optical power in the fundamental mode to the single-wavelength light source 36, and outputs a modulation method designation signal for designating the fundamental modulation method in the fundamental mode to the optical modulator 37. The control unit 12b outputs the received transmission mode information to the digital signal processing unit 32a. The digital signal processing unit 32a receives the transmission mode information output by the control unit 12b. The digital signal processing unit 32a generates a transmission data signal so that the received transmission mode information is included in an empty area in the overhead of the transmission frame. The digital signal processing unit 32a outputs the generated transmission data signal, which is an electrical signal, to the optical modulator 37. The optical modulator 37 optically modulates the continuous light of the fundamental wavelength output by the single-wavelength light source 36 in accordance with a predetermined modulation method for the fundamental mode, based on the transmission data signal output by the digital signal processing unit 32a.

[0135] The optical modulator 37 outputs an optical signal generated by optical modulation to the IF unit 31. The IF unit 31 accepts the optical signal of the fundamental wavelength output by the optical modulator 37. The IF unit 31 outputs the accepted optical signal to the optical switch unit 15aR. The optical switch unit 15aR outputs the optical signal of the fundamental wavelength output by the IF unit 31 to the wavelength multiplexing unit 8a. The wavelength multiplexing unit 8a combines and wavelength-multiplexes optical signals of multiple wavelengths, including the optical signal of the fundamental wavelength output by the optical switch unit 15aR, and sends the wavelength-multiplexed optical signal to the optical fiber 51R. The wavelength path 61R-B of the fundamental wavelength of the optical fiber 51R transmits the optical signal sent by the optical switch unit 15aR to the wavelength demultiplexing unit 7aX of the optical communication device 2aX (step Sb9-2).

[0136] The wavelength demultiplexing unit 7aX demultiplexes the optical signal transmitted by the optical fiber 51R into wavelengths. The wavelength demultiplexing unit 7aX outputs each of the demultiplexed optical signals to the IF units 22X-1 to 22X-m corresponding to each wavelength. In the case of an optical signal of the fundamental wavelength, the wavelength demultiplexing unit 7aX outputs the optical signal of the fundamental wavelength via the IF units 22X-1 to 22X-m to the optical receiving units 27X-1 to 27X-m provided in all the optical transmitting and receiving units 21aX-1 to 21aX-m connected to the edge function unit 11b of the connecting node equipment 1b. The IF unit 22X-1 of the optical transmitting and receiving unit 21aX-1 accepts the optical signal of the fundamental wavelength output by the wavelength demultiplexing unit 7aX. The IF unit 22X-1 outputs the accepted optical signal of the fundamental wavelength to the optical receiver 28X-1. The optical receiver 28X-1 receives the optical signal output by the IF unit 22X-1 and converts the received optical signal into an electrical signal to generate a received data signal including transmission mode information. The optical receiver 28X-1 outputs the received data signal including the transmission mode information to the digital signal processor 23aX-1. The digital signal processor 23aX-1 receives the received data signal including the transmission mode information output by the optical receiver 28X-1.

[0137] The digital signal processing unit 23aX-1 reads transmission mode information from the overhead area of ​​the received data signal. The digital signal processing unit 23aX-1 outputs the read transmission mode information to the control unit 71aX-1. The control unit 71aX-1 reads the transmission mode information output by the digital signal processing unit 23aX-1, and discards the read transmission mode information if the address information included in the read transmission mode information does not match the address information assigned to the optical transceiver 21aX-1 stored in its internal storage area. In response to this, if the address information included in the read transmission mode information matches the address information assigned to the optical transceiver 21aX-1, the control unit 71aX-1 outputs an output optical power designation signal indicating the output optical power indicated in the read transmission mode information to the wavelength-tunable light source 25aX-1. The digital signal processing unit 23aX-1 outputs a wavelength designation signal indicating the center wavelength specified in the read transmission mode information to the wavelength-tunable light source 25aX-1. As a result, the wavelength-tunable light source 25aX-1 generates and outputs continuous light of the wavelength specified by the wavelength specification signal, i.e., continuous light of the output optical power and center wavelength indicated in the transmission mode information, at the output optical power specified by the output optical power specification signal. The wavelength-tunable light source 25aX-1 outputs the generated continuous light to the optical modulator 26X-1.

[0138] The control unit 71aX-1 outputs a modulation method designation signal indicating the modulation method designated in the acquired transmission mode information to the optical modulator 26X-1. The optical modulator 26X-1 performs optical modulation using the modulation method designated by the modulation method designation signal received from the control unit 71aX-1. As a result, the optical modulator 26X-1 stops optical modulation using the basic mode and starts optical modulation using the modulation method designated in the transmission mode information. The control unit 71aX-1 outputs the transmission mode information to the digital signal processing unit 23aX-1. The digital signal processing unit 23aX-1 acquires the transmission mode information output by the control unit 71aX-1 and stores the modulation method, baud rate, bit rate, FEC type, permitted signal bandwidth, and other information indicated in the acquired transmission mode information as setting parameters in an internal storage area. When generating a transmission data signal, the digital signal processing unit 23aX-1 generates the transmission data signal based on the setting parameters stored in an internal storage area and outputs the signal to the optical modulator 26X-1 (step Sb10). Note that the control unit 71aX-1 may store the modulation method, baud rate, bit rate, FEC type, permitted signal band, and the like indicated in the transmission mode information as setting parameters in an internal storage area. In this case, the control unit 71aX-1 outputs the setting parameters to the digital signal processing unit 23aX-1 when the digital signal processing unit 23aX-1 generates the transmission data signal.

[0139] The control unit 12b of the connection node device 1b detects identification information for identifying the optical transmission path 51 from an address-route correspondence table stored in an internal storage area or from an address-route correspondence table acquired on demand, based on the connection source address information included in the received transmission mode information (here, address information assigned to the optical transceiver 21aX-1). Based on the detected identification information for identifying the optical transmission path 51, the received identification information for identifying the optical transmission path 52-i, and the center wavelength specified in the transmission mode information, the control unit 12b generates a switching instruction signal for connecting the wavelength path of the optical transmission path 51, which has the center wavelength specified in the transmission mode information, to the wavelength path of the optical transmission path 52-i, which has the center wavelength specified in the transmission mode information. The control unit 12b outputs the generated switching instruction signal to the output port switching unit 14a.

[0140] 11, the control unit 12b outputs a switching instruction signal to the optical switch unit 15aT of the output port switching unit 14a to change the connection destination of the wavelength route 61T-1, which is a wavelength route of the optical fiber 51T and has a center wavelength specified in the transmission mode information, to the wavelength route 62T-i, which is a wavelength route of the optical fiber 52T-i and has a center wavelength specified in the transmission mode information. The control unit 12b outputs a switching instruction signal to the optical switch unit 15aR to change the connection destination of the wavelength route 61R-1, which is a wavelength route of the optical fiber 51R and has a center wavelength specified in the transmission mode information, to the wavelength route 62R-i, which is a wavelength route of the optical fiber 52R-i and has a center wavelength specified in the transmission mode information.

[0141] Upon receiving a switching instruction signal from the control unit 12b, the optical switch unit 15aT connects the wavelength path 61T-1 of the optical fiber 51T to the wavelength path 62T-i of the optical fiber 52T-i. Upon receiving a switching instruction signal from the control unit 12b, the optical switch unit 15aR connects the wavelength path 61R-1 of the optical fiber 51R to the wavelength path 62R-i of the optical fiber 52R-i (step Sb11). As a result, the optical transceiver 21aX-1 and the optical transceiver 21aY-i are connected via the wavelength path 61T-1 and the wavelength path 62T-i, and the wavelength path 61R-1 and the wavelength path 62R-i.

[0142] Thereafter, for example, it is assumed that the optical transceiver 21aX-m transmits connection request data, the connection destination address information of which is the optical transceiver 21aY-j of the optical communication device 2bY-j, to the connecting node apparatus 1b via the wavelength path 61T-B of the fundamental wavelength at the timing indicated by the timing signal received from the transmission control unit 29X. In this case, as shown in Fig. 12, the optical transceiver 21aX-m and the optical transceiver 21aY-j are connected via the wavelength path 61T-2 included in the optical transmission path 51 and the wavelength path 62T-j included in the optical transmission path 52, and the wavelength path 61R-2 included in the optical transmission path 51 and the wavelength path 62R-j included in the optical transmission path 52. Here, j is an arbitrary integer between 1 and n and is an integer different from i.

[0143] The processing order of steps Sb8-1 and Sb8-2 may be parallel, or steps Sb8-1 and Sb8-2 may be performed in that order, or steps Sb8-1 and Sb8-2 may be performed in reverse order.

[0144] In the configuration of the above-described third embodiment, the optical transceiver 21aX-s (where s is any integer between 1 and m) among the optical transceivers 21aX-1 to 21aX-m included in the optical communication device 2aX and corresponding to the connection source address information of the connection request data receives transmission mode information that the control unit 12b of the connecting node device 1b receives from the operation device 4b and sends to the optical transmission path 51, and transmits and receives optical signals through a wavelength path of the center wavelength specified by the received transmission mode information and included in the optical transmission path 51. The optical transceiver 21aY-i included in the optical communication device 2bY-i transmits and receives optical signals through a wavelength path of the center wavelength specified by the transmission mode information received from the operation device 4b and included in the optical transmission path 52-i. After the control unit 12b of the connecting node apparatus 1b transmits the transmission mode information to the optical communication device 2aX through the optical transmission path 51, the output port switching unit 14a of the connecting node apparatus 1b performs a switching process to connect the optical transceiver 21aX-s included in the optical communication device 2aX and the optical transceiver 21aY-i included in the optical communication device 2bY-i via the wavelength path specified by the transmission mode information included in the optical transmission path 51 and the wavelength path specified by the transmission mode information included in the optical transmission path 52-i. As a result, when connecting the optical transceivers 21aX-s and 21Y-i included in the optical communication devices 2aX and 2bY-i via wavelength paths specified by the transmission modes included in the multiple optical transmission paths 51 and 52-i, the connection can be made using an optical path of the optimal transmission mode without manual intervention. This makes it possible to reduce the cost and time required for setting up optical paths.

[0145] In the third embodiment, the connection information generating unit 38a of the connecting node apparatus 1b calculates the transmission path information of the optical transmission path 51 each time the digital signal processing unit 32a outputs connection request data, BER, and optical input information to the connection information generating unit 38a. However, the following configuration may also be adopted. The transmission path information is not different for each wavelength path included in the optical transmission path 51, and the transmission path information of each wavelength path included in the optical transmission path 51 is the same as the transmission path information of the optical transmission path 51. Therefore, the connection information generating unit 38a stores the calculated transmission path information of the optical transmission path 51 in an internal storage area. When the digital signal processing unit 32a next receives connection request data and outputs the connection request data, BER, and optical input information to the connection information generating unit 38a, the connection information generating unit 38a may read the transmission path information of the optical transmission path 51 stored in the internal storage area and generate connection information, rather than recalculating the transmission path information of the optical transmission path 51.

[0146] In the third embodiment, the optical transmitters and receivers 21aX-1 to 21aX-m transmit optical input information to the connecting node apparatus 1b, and the connecting node apparatus 1b transmits the optical input information to the operation apparatus 4b. The optical input information can be generated in advance if information about the optical transmitters and receivers 21aX-1 to 21aX-m, such as the transceiver type and the number of transceivers, is known. Therefore, the transmission path design unit 42b of the operation apparatus 4b may store the optical input information it generates in an internal storage area in association with address information. In this case, when calculating the transmission path characteristics, the transmission path design unit 42b reads out the optical input information corresponding to the connection source address information included in the connection request data stored in the internal storage area and calculates the transmission path characteristics. The digital signal processing units 23aX-1 to 23aX-m do not need to transmit the optical input information, and the connection information generated by the connection information generation unit 38a of the connecting node apparatus 1b does not include the optical input information.

[0147] In the optical transmission system 102 of the third embodiment described above, the optical transmitters and receivers 21aX-1 to 21aX-m and the connecting node apparatus 1b are connected by one optical transmission path 51. In contrast to this, an optical transmission system 102a shown in FIG. 13 may be configured in which the optical transmitters and receivers 21aX-1 to 21aX-m are connected to different optical transmission paths 51-1 and 51-2. As shown in FIG. 13, in the optical transmission system 102a, the optical communication apparatus 2dX and the connecting node apparatus 1b are connected to two optical transmission paths 51-1 and 51-2. Note that the wavelength multiplexing / demultiplexing units 6aX-1 and 6aX-2 included in the optical communication apparatus 2dX have the same configuration as the wavelength multiplexing / demultiplexing unit 6aX. The output port switching unit 14a of the connection node device 1b includes two wavelength demultiplexing units 7a: one wavelength demultiplexing unit 7a connecting the optical fiber 51T-1 included in the optical transmission path 51-1 and the optical switch unit 15aT, and another wavelength demultiplexing unit 7a connecting the optical fiber 51T-2 included in the optical transmission path 51-2 and the optical switch unit 15aT. The output port switching unit 14a includes two wavelength multiplexing units 8a: one wavelength demultiplexing unit 8a connecting the optical fiber 51R-1 included in the optical transmission path 51-1 and the optical switch unit 15aR, and another wavelength multiplexing unit 8a connecting the optical fiber 51R-2 included in the optical transmission path 51-2 and the optical switch unit 15aR.

[0148] In the optical transmission system 102a, the optical transmitters and receivers 21aX-1 to 21aX-(mk) included in the optical communication device 2dX are connected to an optical transmission path 51-1 via a wavelength multiplexing / demultiplexing unit 6aX-1, and the optical transmitters and receivers 21aX-(m-k+1) to 21aX-m are connected to an optical transmission path 51-2 via a wavelength multiplexing / demultiplexing unit 6aX-2, where k is an integer between 1 and (m-1). In this case, the optical transmitters and receivers 21aX-1 to 21aX-m transmit connection request data in order according to the timing indicated by the timing signal output by the transmission control unit 29X, and are connected to one of the optical transmitters and receivers 21aY-1 to 21aY-n via the wavelength paths 61-1-1, 61-2-1, ... of the optical transmission path 51-1 or the wavelength paths 61-1-2, 61-2-2, ... of the optical transmission path 51-2 to which they are connected.

[0149] In the third embodiment, if the transmission mode information includes the number of WDM wavelengths, the control units 71aX-1 to 71aX-m may output the transmission mode information to the control unit 20aX. When the control unit 20aX receives transmission mode information output by one of the control units 71aX-1 to 71aX-m, the control unit 20aX references the number of WDM wavelengths included in the received transmission mode information. When the number of optical transceivers 21aX-1 to 21aX-m already connected to the optical transceivers 21aX-1 to 21aY-n included in the optical communication devices 2bY-1 to 2bY-n matches the referenced number of WDM wavelengths, the control unit 20aX outputs a communication stop instruction signal to the control unit 71aX-1 to 71aX-m that outputs the transmission mode information, to stop the optical transceivers 21aX-1 to 21aX-m that includes the control unit 71aX-1 to 71aX-m that output the transmission mode information from communicating using optical signals. This makes it possible to prevent communication using optical signals that exceed the number of wavelengths that can be multiplexed by the wavelength multiplexing unit 8aX included in the wavelength multiplexing / demultiplexing unit 6aX. As the number of WDM wavelengths increases, the transmission distance becomes shorter, and it is possible that optical signals transmitted by the optical communication device 2dX will not reach the optical communication devices 2bY-1 to 2bY-n to which the optical transmitters and receivers 21aX-1 to 21aX-m are connected. Even when the number of WDM wavelengths increases in this way, it is possible to prevent the transmitted optical signals from not reaching the optical communication devices 2bY-1 to 2bY-n by limiting the number of optical transmitters and receivers 21aX-1 to 21aX-m using the communication stop instruction signal.

[0150] In the first, second, and third embodiments described above, the connecting node devices 1, 1a, and 1b must transmit transmission mode information to the optical transmission path 51 before the output port switching units 14 and 14a perform the switching process. In this case, in the processes of steps S5-2, Sa8-2, and Sb9-2, there is a time lag between when the control units 12, 12a, and 12b output the transmission mode information to the digital signal processing units 32 and 32a and when the optical switch units 15R and 15aR output the optical signal including the transmission mode information. Therefore, the time lag must be measured in advance, and the control units 12, 12a, and 12b must perform the processes of outputting the switching instruction signal in steps S7, Sa10, and Sb11 after the elapse of the measured time from when they output the transmission mode information to the digital signal processing units 32 and 32a.

[0151] In order to ensure the timing of starting the processes of steps S7, Sa10, and Sb11, the following may be adopted. For example, when the control units 71X, 71aX-1 to 71aX-m of the optical transceivers 21X, 21aX-1 to 21aX-m receive the transmission mode information, they output information indicating that reception of the transmission mode information has been completed to the digital signal processing units 23X, 23aX-1 to 23aX-m in the basic mode. The digital signal processing units 23X, 23aX-1 to 23aX-m transmit information indicating that reception of the transmission mode information has been completed to the connecting node devices 1, 1a, and 1b. The control units 12, 12a, and 12b of the connecting node devices 1, 1a, and 1b may output a switching instruction signal to the output port switching units 14, 14a at the timing when they receive the information indicating that reception of the transmission mode information transmitted by the optical transceivers 21X, 21aX-1 to 21aX-m has been completed.

[0152] To ensure the timing of starting the processing of steps S7, Sa10, and Sb11, the following may be done: In the processing of steps S6-2, Sa9, and Sb10, when the optical modulator 26X, 26X-1 to 26X-m stops optical modulation in the fundamental mode, the digital signal processing unit 32, 32a of the connecting node device 1, 1a, 1b detects that the optical modulation in the fundamental mode of the optical transmitter / receiver 21X, 21aX-1 to 21aX-m has stopped, based on the presence or absence of an optical signal in the fundamental mode transmitted by the optical transmitter / receiver 21X, 21aX-1 to 21aX-m. The digital signal processing units 32, 32a may notify the control units 12, 12a, 12b that the optical modulation in the basic mode of the optical transceivers 21X, 21aX-1 to 21aX-m, i.e., the optical output in the basic mode, has stopped, and the control units 12, 12a, 12b may output a switching instruction signal to the output port switching units 14, 14a at the timing of receiving the notification.

[0153] (Another configuration example of the second and third embodiments) For the sake of convenience, the following description will be given below regarding a case where the light source used to generate the optical signal on the side transmitting the connection request data is a single-wavelength light source as another configuration example of the second embodiment, and a case where the light source used to generate the optical signal on the side transmitting the connection request data is a tunable wavelength light source as another configuration example of the third embodiment. Note that in the following description of the other configuration examples of the second and third embodiments, the same components as those in the first to third embodiments are denoted by the same reference numerals.

[0154] (Configuration to avoid collisions in connection request data (part 1)) 14 is a block diagram showing the configuration of an optical transmission system 101b which is another configuration example of the second embodiment. The optical transmission system 101b includes optical communication devices 2X-1 to 2X-m, a connecting node device 1c, optical communication devices 2Y-1 to 2Y-n, an operation device 4, optical transmission paths 51-1 to 51-m connecting each of the optical communication devices 2X-1 to 2X-m with the connecting node device 1c, optical transmission paths 52-1 to 52-n connecting each of the optical communication devices 2Y-1 to 2Y-n with the connecting node device 1c, a connection line 3 connecting the operation device 4 with the connecting node device 1c, and connection lines 3-1 to 3-n connecting the operation device 4 with each of the optical communication devices 2Y-1 to 2Y-n.

[0155] The connection node apparatus 1c comprises an edge function unit 11c and an output port switching unit 14. The output port switching unit 14 connects optical transmission paths 51-1 to 51-m, a connection information processing unit 13 of the edge function unit 11c, and optical communication devices 2Y-1 to 2Y-n. In an initial state, the output port switching unit 14 sets the connection destination of the optical transmission paths 51-1 to 51-m to the connection information processing unit 13 of the edge function unit 11c. When the output port switching unit 14 receives a switching instruction signal from the control unit 12c, it performs switching processing to connect one of the optical transmission paths 51-1 to 51-m to one of the optical transmission paths 52-1 to 52-n in accordance with the received switching instruction signal.

[0156] The edge function unit 11c includes a connection information processing unit 13 and a control unit 12c. The control unit 12c includes the following components in addition to the components included in the control unit 12a of the second embodiment. In the optical transmission system 101b, unlike the optical transmission system 102 shown in FIG. 8, where one optical communication device 2aX includes multiple optical transceivers 21aX-1 to 21aX-m, each of the multiple optical communication devices 2X-1 to 2X-m includes one optical transceiver 21X-1 to 21X-m. Therefore, unlike the optical transmission system 102, it is not possible to stagger the timing of transmitting connection request data using a transmission control unit 29X.

[0157] To enable different timings for transmitting the connection data, the control unit 12c outputs timing information including the timing for transmitting the connection request data and address information of the optical transceivers 21X-1 to 21X-m that are permitted to transmit the connection request data to the digital signal processing unit 32 of the connection information processing unit 13. Thereafter, the timing information is transmitted to the optical transceivers 21X-1 to 21X-m by processing similar to that when transmission mode information is transmitted by a transmission data signal.

[0158] Each of the optical communication devices 2X-1 to 2X-m has the same configuration as the optical communication device 2X of the first embodiment, but adds a processing configuration for receiving an optical signal containing the timing information. When timing information is included in the received data signal output from the optical receivers 28X-1 to 28X-m, the digital signal processing units 23X-1 to 23X-m included in each of the optical communication devices 2X-1 to 2X-m read the timing information. The digital signal processing units 23X-1 to 23X-m output the read timing information to the control units 71X-1 to 71X-m connected to each of the optical communication devices 2X-1 to 2X-m. When address information included in the timing information output from the digital signal processing units 23X-1 to 23X-m is address information assigned to the optical transceivers 21X-1 to 21X-m included in the control units 71X-1 to 71X-m and stored in their internal storage areas, the control units 71X-1 to 71X-m output connection request data according to the timing indicated in the timing information. This allows the optical transmitters and receivers 21X-1 to 21X-m to transmit connection request data at different times.

[0159] (Configuration to avoid collisions in connection request data (part 2)) 15 is a block diagram showing the configuration of an optical transmission system 102b, which is another example of the configuration of the third embodiment. The optical transmission system 102b includes optical communication devices 2eX-1 to 2eX-m, a connection node device 1d, an optical communication device 2fY, an operation device 4c, a wavelength multiplexing / demultiplexing device 6X, a wavelength multiplexing / demultiplexing device 6Y, an optical transmission path 51, an optical transmission path 52, a connection line 3, and a connection line 3-1 connecting the operation device 4c and the optical communication device 2fY. The optical transmission path 51 connects the wavelength multiplexing / demultiplexing device 6X and the connection node device 1d. The optical transmission path 52 connects the wavelength multiplexing / demultiplexing device 6Y and the connection node device 1d. The connection line 3 connects the operation device 4c and the connection node device 1d. The connection line 3-1 connects the operation device 4c and the optical communication device 2fY.

[0160] The optical communication devices 2eX-1 to 2eX-m each include an optical transceiver 21aX-1 to 21aX-m and a control unit 20X-1 to 20X-m. The optical communication device 2fY includes optical transceivers 21aY-1 to 21aY-n and a control unit 20aY. The operation device 4c includes a path detector 41 and a transmission path design unit 42c.

[0161] The transmission path design unit 42c has the same configuration as the transmission path design unit 42b of the third embodiment, except for the following configuration. The transmission path design unit 42b references a connection line table stored in an internal storage area and transmits transmission mode information to the control units 20Y-1 to 20Y-n of the optical communication devices 2bY-1 to 2bY-n through the connection lines 3-1 to 3-n corresponding to the connection destination address information included in the connection request data. In contrast, the transmission path design unit 42c adds the connection destination address information included in the connection request data to the generated transmission mode information and transmits it to the control unit 20aY of the optical communication device 2fY through the connection line 3-1. Therefore, the transmission path design unit 42c does not need to store a connection line table in an internal storage area in advance. As described with reference to FIG. 7, when the control unit 20aY receives the transmission mode information to which the destination address information is assigned and which is transmitted by the transmission path design unit 42c via the connection line 3-1, the control unit 20aY outputs the transmission mode information to one of the optical transceivers 21aY-1 to 21aY-n corresponding to the destination address information assigned to the received transmission mode information.

[0162] The wavelength multiplexing / demultiplexing devices 6X and 6Y are standalone devices of the wavelength multiplexing / demultiplexing unit 6aX included in the optical transmission system 102 shown in Fig. 8, and the wavelength multiplexing / demultiplexing device 6X includes a wavelength demultiplexing unit 7aX and a wavelength multiplexing unit 8aX, while the wavelength multiplexing / demultiplexing device 6Y includes a wavelength demultiplexing unit 7aY and a wavelength multiplexing unit 8aY. Note that, similar to the optical communication device 2aX of the optical transmission system 102 shown in Fig. 8, the optical communication device 2fY may be configured to include the wavelength multiplexing / demultiplexing device 6Y as an internal functional unit, i.e., as the wavelength multiplexing / demultiplexing unit 6aY.

[0163] The connection node device 1d includes an edge functional unit 11d and an output port switching unit 14a. The output port switching unit 14a connects a wavelength path 61-B of the fundamental wavelength included in the optical transmission line 51 to a connection information processing unit 13b of the edge functional unit 11d, and performs switching processing to connect one of the wavelength paths 61-1 to 61-m included in the optical transmission line 51 to one of the wavelength paths 62-1 to 62-n included in the optical transmission line 52 in response to a switching instruction signal from the control unit 12d.

[0164] The edge function unit 11d includes a connection information processing unit 13b and a control unit 12d. In addition to the components included in the connection information processing unit 13a and the control unit 12b of the third embodiment, the connection information processing unit 13b and the control unit 12d include the following components. In the optical transmission system 102b, similar to the optical transmission system 101b shown in FIG. 14, each of the multiple optical communication devices 2eX-1 to 2eX-m includes one optical transceiver unit 21aX-1 to 21aX-m. Therefore, unlike the optical transmission system 102 shown in FIG. 8, it is not possible to set different timings for transmitting connection request data using the transmission control unit 29X.

[0165] The connection information processing unit 13b and the control unit 12d are configured to allocate different fundamental wavelengths to the optical transceivers 21aX-1 to 21aX-m to prevent connection request data from colliding with each other on the fundamental wavelength wavelength path 61-B. The connection information processing unit 13b is equipped with a tunable light source having the same configuration as the tunable light source 25aX-1 shown in FIG. 9, for example, instead of the single-wavelength light source 36. Hereinafter, the tunable light source provided in the connection information processing unit 13b will be referred to as the tunable light source 36a, with the symbol "36a" added. The digital signal processing unit 32a is connected to the tunable light source 36a and outputs a wavelength designation signal to the tunable light source 36a.

[0166] The control unit 12d assigns different fundamental wavelengths to each of the optical transceivers 21aX-1 through 21aX-m. To this end, the control unit 12d pre-selects fundamental wavelengths to be assigned to each of the optical transceivers 21aX-1 through 21aX-m, and stores the selected fundamental wavelengths in an internal storage area in association with address information for each of the optical transceivers 21aX-1 through 21aX-m. The control unit 12d outputs fundamental wavelength designation information, including the address information for each of the optical transceivers 21aX-1 through 21aX-m stored in the internal storage area and the corresponding fundamental wavelength, to the digital signal processing unit 32a of the connection information processing unit 13b. Thereafter, the fundamental wavelength designation information is transmitted to the optical transceivers 21aX-1 to 21aX-m in the fundamental mode before the fundamental wavelength was changed, i.e., through the wavelength path 61-B of the optical transmission path 51, by processing similar to that when the transmission mode information is transmitted by the transmission data signal.

[0167] Each of the optical transmitters and receivers 21aX-1 to 21aX-m has the same configuration as the optical transmitters and receivers 21aX-1 to 21aX-m of the third embodiment, but with the addition of a processing configuration for receiving an optical signal including the fundamental wavelength designation information. The digital signal processors 23aX-1 to 23aX-m included in each of the optical transmitters and receivers 21aX-1 to 21aX-m read out the fundamental wavelength designation information when the fundamental wavelength designation information is included in the received data signal output by the optical receivers 28X-1 to 28X-m. The digital signal processors 23aX-1 to 23aX-m output the read fundamental wavelength designation information to the controllers 71aX-1 to 71aX-m connected to each of them. The control units 71aX-1 to 71aX-m receive the fundamental wavelength designation information output by the digital signal processing units 23aX-1 to 23aX-m, and read out their own address information included in the received fundamental wavelength designation information, i.e., the fundamental wavelength corresponding to the address information stored in their internal storage areas. Each of the control units 71aX-1 to 71aX-m outputs a wavelength designation signal that designates the read fundamental wavelength to the corresponding wavelength-tunable light sources 25aX-1 to 25aX-m.

[0168] As a result, each of the optical transmitters and receivers 21aX-1 to 21aX-m generates an optical signal with a different fundamental wavelength. For example, when transmitting transmission mode information, the control unit 12d reads out the fundamental wavelength corresponding to the connection source address information included in the transmission mode information from an internal storage area. The control unit 12d generates a wavelength designation signal based on the read information indicating the fundamental wavelength. The control unit 12d outputs the generated wavelength designation signal to the tunable wavelength light source 36a. The tunable wavelength light source 36a generates and outputs continuous light having the fundamental wavelength designated by the wavelength designation signal. This changes the fundamental wavelength of the continuous light generated by the tunable wavelength light source 36a. The control unit 12d outputs the transmission mode information to the digital signal processing unit 32a. The digital signal processing unit 32a receives the transmission mode information output by the control unit 12d and generates a transmission data signal including the received transmission mode information. The digital signal processing unit 32a outputs the generated transmission data signal to the optical modulator 37. The optical modulator 37 modulates the continuous light with the changed fundamental wavelength output from the wavelength-tunable light source 36a based on the transmission data signal to generate an optical signal.

[0169] As a result, the optical transmitters and receivers 21aX-1 to 21aX-m and the connecting node apparatus 1d are connected using different fundamental wavelengths, making it possible to avoid collisions of connection request data. However, in this case, if the optical transmitters and receivers 21aX-1 to 21aX-m transmit connection request data using the fundamental wavelengths assigned to them, the connection request data will collide at the optical receiver 34 of the connecting node apparatus 1b. To avoid this collision, the connecting node apparatus 1d needs to individually terminate wavelength paths of multiple different fundamental wavelengths. For example, assume that the maximum number of fundamental wavelengths assigned by the connecting node apparatus 1d is predetermined. The optical receiver 33 of the connection information processing unit 13b of the connecting node apparatus 1d includes multiple optical receivers 34, the number of which matches the maximum number of fundamental wavelengths, and the optical switch unit 15aT of the output port switching unit 14a connects the output of the wavelength demultiplexer 7a to the multiple optical receivers 34 so that each of the multiple optical receivers 34 is connected to a different fundamental wavelength. In this way, the control unit 12d of the connection node device 1d can distinguish and take in the connection request data transmitted by each of the optical transceivers 21aX-1 to 21aX-m. Note that, instead of the optical receiving unit 33 being equipped with a plurality of optical receivers 34, the edge function unit 11d may be equipped with a plurality of connection information processing units 13b, the number of which corresponds to the maximum number of fundamental wavelengths.

[0170] The above-described configurations (1) and (2) for avoiding collisions of connection request data are configured to transmit initial setting information for avoiding collisions of connection request data, such as timing information or fundamental wavelength setting information, from the control units 12c and 12d of the connecting node devices 1c and 1d to the optical transceivers 21X-1 to 21X-m and 21aX-1 to 21aX-m. The means for transmitting the initial setting information for avoiding collisions of connection request data from the connecting node devices 1c and 1d may be applied to, for example, the optical transmission system 102 shown in FIG. 8, and used in combination with a means for varying the timing of transmitting connection request data using the transmission control unit 29X. By using these in combination, collisions of connection request data can be avoided more reliably. In the optical transmission system 102 shown in FIG. 8, the control unit 12b of the connection node device 1b may transmit in advance to the transmission control unit 29X of the optical communication device 2aX initial setting information including information indicating the timing of transmission of the connection request data, and the transmission control unit 29X may respond by transmitting information indicating that reception of the initial setting information has been completed to the control unit 12b, so that after the timing of transmission and reception of the connection request data is shared between them, the transmission control unit 29X may output a timing signal to each of the optical transmission and reception units 21aX-1 to 21aX-m based on the information indicating the timing of transmission of the connection request data included in the initial setting information.

[0171] A configuration for transmitting timing information provided by the control unit 12c of the optical transmission system 101b shown in FIG. 14 may be added to the control unit 12d of the optical transmission system 102b shown in FIG. 15, so that the control unit 12d may use both the means for changing the fundamental wavelength and the means for transmitting a timing signal, or may use either one of the means.

[0172] As a method for avoiding collisions of connection request data, for example, the following method may be applied. If there is no response from the connection node devices 1c and 1d for a predetermined period of time after each of the optical transmitters and receivers 21X-1 to 21X-m and 21aX-1 to 21aX-m transmits connection request data, for example, if transmission mode information with the destination being the optical transmitters and receivers 21X-1 to 21X-m and 21aX-1 to 21aX-m is not obtained, the optical transmitters and receivers 21X-1 to 21X-m and 21aX-1 to 21aX-m may stop optical output in basic mode for a predetermined period of time or for a randomly determined period of time. This makes it possible to reduce the probability of collisions of connection request data occurring.

[0173] (Configuration in which connection node device includes wavelength conversion unit) 16 is a block diagram showing the configuration of an optical transmission system 101c according to another example of the second embodiment. The optical transmission system 101c includes a connecting node apparatus 1e, an optical communication apparatus 2X, a plurality of optical communication apparatuses 2bY-1 to 2bY-n, an operation apparatus 4d, a wavelength multiplexing / demultiplexing apparatus 6Y, an optical transmission path 51, an optical transmission path 52, a connection line 3, and connection lines 3-1 to 3-n. The optical transmission path 51 connects the optical communication apparatus 2X and the connecting node apparatus 1e. The optical transmission path 52 connects the wavelength multiplexing / demultiplexing apparatus 6Y and the connecting node apparatus 1e. The connection line 3 connects the operation apparatus 4d and the connecting node apparatus 1e. The connection lines 3-1 to 3-n connect the operation apparatus 4d and each of the optical communication apparatuses 2bY-1 to 2bY-n.

[0174] The connection node apparatus 1e includes an edge function unit 11e and an output port switching unit 14. The edge function unit 11e includes a control unit 12e, a connection information processing unit 13, and a wavelength conversion unit 16. The control unit 12e has the same configuration as the control unit 12a of the second embodiment except for the configuration described below. That is, the control unit 12e transmits, to the operation device 4d via the connection line 3, information that the connection node apparatus 1e includes a wavelength conversion unit 16 and information indicating a wavelength band that can be converted by the wavelength conversion unit 16 (hereinafter, these two pieces of information will be collectively referred to as "wavelength conversion unit information"), connection information output by the connection information processing unit 13, and connection request data. The control unit 12e outputs information on the center wavelength included in the transmission mode information transmitted by a transmission path design unit 42d of the operation device 4d to the wavelength conversion unit 16.

[0175] The operation device 4d includes a route detection unit 41 and a transmission route design unit 42d. The transmission route design unit 42d has the same configuration as the transmission route design unit 42 of the second embodiment, except for the following configuration. The transmission route design unit 42 either stores transmission route information for each of the optical transmission routes 52-1 to 52-n in an internal storage area in advance, or acquires the transmission route information for each of the optical transmission routes 52-1 to 52-n on demand. In contrast, the transmission route design unit 42d either stores transmission route information for the optical transmission route 52 in an internal storage area in advance, or acquires the transmission route information for the optical transmission route 52 on demand. The transmission route design unit 42d selects configuration information through a predetermined selection process based on the calculated transmission route characteristics, information indicating available resources of the optical transmission route 52 corresponding to the destination address information detected by the route detection unit 41, desired bit rate information and specification information of the optical transmission / reception unit 21X included in the connection request data, and wavelength conversion unit information. The transmission path design unit 42d generates transmission mode information including the selected configuration information.

[0176] In the optical transmission system 101c, the following processing is performed by providing the above-described configuration. This processing will be described with reference to the flowchart shown in FIG. 6. First, the processing of steps Sa1 and Sa2 shown in FIG. 6 is performed. However, in step Sa1, it is assumed that the control unit 20X of the optical communication device 2X generates a connection request instruction signal including, as address information of the connection destination, address information of the optical transceiver 21aY-i provided in the optical communication device 2bY-i, and that the optical communication device 2aY-i is connected to the connection line 3-i. In the processing of step Sa3, the control unit 12e transmits wavelength conversion unit information in addition to the connection information and connection request data to the operation device 4d via the connection line 3.

[0177] In the process of step Sa4, the route detection unit 41 of the operation device 4d detects identification information that identifies the optical transmission path 52 corresponding to the address information of the optical transceiver 21aY-i, based on the connection request data. In the process of step Sa5, the transmission path design unit 42d acquires the identification information that identifies the optical transmission path 52 output by the route detection unit 41. The transmission path design unit 42d either reads and acquires the transmission path information of the optical transmission path 52 that corresponds to the acquired identification information that identifies the optical transmission path 52 from an internal storage area, or acquires the transmission path information of the optical transmission path 52 on demand. The transmission path design unit 42d calculates transmission path characteristics based on the acquired transmission path information of the optical transmission path 52 and the received connection information.

[0178] In the processing of step Sa6, the transmission path design unit 42d selects configuration information by a predetermined selection process based on the calculated transmission path characteristics, the received wavelength conversion unit information, and the desired bit rate information and specification information of the optical transceiver 21X included in the received connection request data. The transmission path design unit 42d generates transmission mode information including the selected configuration information and the connection source address information included in the connection request data.

[0179] In the process of step Sa7-1, the transmission path design unit 42d refers to the connection line table stored in an internal storage area, and transmits the generated transmission mode information to the control unit 20Y-i of the optical communication device 2bY-i through the connection line 3-i corresponding to the connection destination address information included in the connection request data. Thereafter, instead of the process of step Sa8-1, the same process as step Sb9-1 shown in FIG. 10 is performed by the control unit 20Y-i and the optical transceiver 21aY-i.

[0180] As a result, in the optical transceiver 21aY-i, the tunable light source 25aY-i generates continuous light having the output optical power indicated in the transmission mode information and the center wavelength indicated in the transmission mode information, and outputs the generated continuous light to the optical modulator 26Y-i. The optical modulator 26Y-i performs optical modulation using the modulation method indicated in the transmission mode information. The digital signal processor 23aY-i generates a transmission data signal based on setting parameters such as the modulation method, baud rate, bit rate, FEC type, and permitted signal band indicated in the transmission mode information, and outputs the generated transmission data signal to the optical modulator 26Y-i.

[0181] In the processing of step Sa7-2, the transmission path design unit 42d transmits the generated transmission mode information and identification information for specifying the optical transmission path 52 detected by the path detection unit 41 to the connecting node apparatus 1e through the connection line 3. Thereafter, the processing of steps Sa8-2 and Sa9 is performed by the control unit 12e, connection information processing unit 13, output port switching unit 14, and optical transceiver unit 21X of the optical communication device 2X of the connecting node apparatus 1e.

[0182] In the processing of step Sa10, the control unit 12e of the connecting node device 1e outputs information indicating the center wavelength included in the transmission mode information received through the connection line 3 to the wavelength conversion unit 16. The control unit 12e detects identification information identifying the optical transmission path 51 from an address path correspondence table stored in an internal storage area or an address path correspondence table acquired on demand, based on connection source address information included in the transmission mode information (here, address information of the optical transceiver 21X). The control unit 12e generates a switching instruction signal based on the detected identification information identifying the optical transmission path 51 and identification information identifying the optical transmission path 52 received from the transmission path design unit 42d of the operation device 4d. The control unit 12e outputs the generated switching instruction signal to the output port switching unit 14. As a result, the output port switching unit 14 connects the optical transmission path 51 and the wavelength conversion unit 16.

[0183] When the optical transceiver 21X of the optical communication device 2X transmits an optical signal to the connecting node device 1e through the optical transmission path 51, the output port switching unit 14 of the connecting node device 1e outputs the optical signal received through the optical transmission path 51 to the wavelength converter 16. The wavelength converter 16 accepts the optical signal output by the output port switching unit 14. The wavelength converter 16 converts the wavelength of the accepted optical signal to a center wavelength provided by the control unit 12e and transmits the converted optical signal to the optical transmission path 52. Here, the center wavelength provided by the control unit 12e is the center wavelength indicated in the transmission mode information. Therefore, the wavelength of the optical signal that the wavelength converter 16 transmits to the optical transmission path 52 is the same as the wavelength of the optical signal transmitted by the optical transceiver 21aY-1 of the optical communication device 2bY-i. Therefore, if the wavelength path of the center wavelength indicated in the transmission mode information is designated as wavelength path 62-i, the wavelength converter 16 and the optical transceiver 21aY-i are connected by the wavelength path 62-i.

[0184] The optical signal sent from the wavelength converter 16 to the optical transmission line 52 is transmitted via wavelength path 62-i to a wavelength demultiplexer 7aY included in the wavelength multiplexer / demultiplexer 6Y. The wavelength demultiplexer 7aY demultiplexes the wavelength-multiplexed optical signal transmitted by the optical transmission line 52 into individual wavelengths. The wavelength demultiplexer 7aY outputs each of the demultiplexed optical signals to the optical transmitters and receivers 21aY-1 to 21aY-n corresponding to the respective wavelengths. As a result, the optical signal transmitted from the optical transmitter and receiver 21X of the optical communication device 2X reaches the optical transmitter and receiver 21aY-i of the optical communication device 2bY-i.

[0185] In the above optical transmission system 101c, the edge function unit 11e of the connecting node equipment 1e is provided with the wavelength conversion unit 16, so that even if the optical transceiver 21X of the optical communication device 2X is provided with a single-wavelength light source 25X, which is a light source whose wavelength cannot be changed, it can be converted to any wavelength by the wavelength conversion unit 16. Therefore, by using the connecting node equipment 1e, it is possible to switch the wavelength using the optical transceiver 21X, which is lower in cost than the optical transceiver 21aX-1 equipped with the wavelength-tunable light source 25aX-1, and connect to any of the optical transceivers 21aY-1 to 21aY-n through any of the wavelength routes 62-1 to 62-n included in the optical transmission path 52.

[0186] (Other configuration examples) In addition to the configurations shown in the optical transmission systems 101, 101a, 101b, 101c, 102, 102a, and 102b described above, the following configuration may also be used: For example, in the optical transmission system 102 shown in Fig. 8, the optical communication device 2aX may not include a wavelength multiplexing / demultiplexing unit 6aX, and one end of each of the optical transmission lines (the m optical transmission lines are denoted by 51-1 to 51-m) may be connected to each of the optical transmitting / receiving units 21aX-1 to 21aX-m, and the other ends of the optical transmission lines 51-1 to 51-m may be connected to the output port switching unit 14a.

[0187] In the optical transmission system 102a shown in Fig. 13, instead of the optical communication device 2bY-1 connected to the optical transmission line 52-1, an optical communication device 2fY shown in Fig. 15 and a wavelength multiplexing / demultiplexing device 6Y connected to the optical communication device 2fY may be provided, and the wavelength multiplexing / demultiplexing device 6Y may be connected to the optical transmission line 52-1. In the optical transmission system 102a shown in Fig. 13, instead of the optical communication device 2bY-1 connected to the optical transmission line 52-1, optical communication devices 2bY-1 to 2bY-n shown in Fig. 16 and a wavelength multiplexing / demultiplexing device 6Y connected to the optical communication devices 2bY-1 to 2bY-n may be provided, and the wavelength multiplexing / demultiplexing device 6Y may be connected to the optical transmission line 52-1. In the optical transmission system 102a shown in Fig. 13, instead of the optical communication devices 2bY-1 to 2bY-n, an optical communication device 2fY shown in Fig. 15 may be provided, and one optical transceiver 21aY-1 to 21aY-n may be connected to each of the optical transmission paths 52-1 to 52-n. In the optical transmission system 102a shown in Fig. 13, instead of the optical communication device 2dX, two optical communication devices 2aX shown in Fig. 8 may be provided, and the wavelength multiplexing / demultiplexing unit 6aX of one optical communication device 2aX may be connected to the optical transmission path 51-1, and the wavelength multiplexing / demultiplexing unit 6aX of the other optical communication device 2aX may be connected to the optical transmission path 51-2.

[0188] 14, instead of the optical communication devices 2X-1 to 2X-m, a single optical communication device including optical transceivers 21X-1 to 21X-m, one control unit 20aX connected to each of the optical transceivers 21X-1 to 21X-m, and a transmission control unit 29X connected to each of the optical transceivers 21X-1 to 21X-m may be used, and one optical transceiver 21X-1 to 21X-m may be connected to each of the optical transmission paths 51-1 to 51-m. In the optical transmission system 101b shown in FIG. 14, instead of the optical communication devices 2Y-1 to 2Y-n, the optical communication device 2cY shown in FIG. 7 may be used, and one optical transceiver 21Y-1 to 21Y-n may be connected to each of the optical transmission paths 52-1 to 52-n.

[0189] In the optical transmission system 101c shown in FIG. 16, the optical communication device 2X may be replaced with optical communication devices 2X-1 to 2X-m shown in FIG. 14, and instead of a single optical transmission path 51, a plurality of optical transmission paths 51-1 to 51-m may be connected to the output port switching unit 14, and one optical transmission / reception unit 21X-1 to 21X-m may be connected to each of the optical transmission paths 51-1 to 51-m. In the optical transmission system 101c shown in FIG. 16, instead of the optical communication device 2X and the optical transmission path 51, it is also possible to provide one optical communication device including optical transmitters and receivers 21X-1 to 21X-m, one control unit 20aX connected to each of the optical transmitters and receivers 21X-1 to 21X-m, and a transmission control unit 29X connected to each of the optical transmitters and receivers 21X-1 to 21X-m, and optical transmission paths 51-1 to 51-m connected to each of the optical transmitters and receivers 21X-1 to 21X-m and the output port switching unit 14.

[0190] In the optical transmission system 102 shown in Fig. 8, the optical communication device 2aX does not have to include a wavelength multiplexing / demultiplexing unit 6aX internally, but may have it externally as a wavelength multiplexing / demultiplexing device 6X as in the optical transmission system 102b of Fig. 15. Similarly, in the optical transmission system 102a shown in Fig. 13, the optical communication device 2dX does not have to include wavelength multiplexing / demultiplexing units 6aX-1 and 6aX-1 internally, but may have it externally as wavelength multiplexing / demultiplexing devices 6X-1 and 6X-2 as in the optical transmission system 102b of Fig. 15.

[0191] For example, in the third embodiment and other configuration examples of the third embodiment, an optical transceiver having the same configuration as the optical transceiver 21X including the single-wavelength light source 25X shown in Fig. 2 may be applied instead of the optical transceivers 21aX-1 to 21aX-m including the wavelength-tunable light sources 25aX-1 to 25a-m shown in Fig. 9. A configuration not including the operation devices 4, 4a, 4b, 4c, and 4d as in the optical transmission system 100 shown in Fig. 1 may be applied to a configuration including the operation devices 4, 4a, 4b, 4c, and 4d described above.

[0192] In the above-described first to third embodiments and other configuration examples of each embodiment, the control unit 12 of the first embodiment and the transmission path design units 42, 42a, 42b, 42c, and 42d of the second and third embodiments select configuration information that specifies a transmission mode by a predetermined selection process based on the transmission path characteristics, desired bit rate information, and specification information of the optical transceivers 21X, 21X-1 to 21X-m, 21aX, and 21aX-1 to 21aX-m. Alternatively, the transmission mode may be specified as follows.

[0193] For example, several patterns of combinations of transmission path characteristics, desired bit rate information, and specification information of the optical transceivers 21X, 21X-1 to 21X-m, 21aX, and 21aX-1 to 21aX-m are selected. Configuration information for each selected pattern is selected, and a transmission mode information table is generated in advance in which the selected configuration information is associated with each combination of the transmission path characteristics, desired bit rate information, and specification information of the optical transceivers 21X, 21X-1 to 21X-m, 21aX, and 21aX-1 to 21aX-m, and the table is stored in advance in internal storage areas of the control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d. In such a configuration, instead of selecting configuration information, the control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d may refer to a transmission mode information table stored in an internal storage area, read from the transmission mode information table a combination of configuration information corresponding to a combination of transmission path characteristics, desired bit rate information, and specification information of the optical transceivers 21X, 21X-1 to 21X-m, 21aX, and 21aX-1 to 21aX-m, and generate transmission mode information including the read combination of configuration information and the connection source address information included in the connection request data.

[0194] Furthermore, a different number (hereinafter referred to as "transmission mode number") is assigned to each record of the transmission mode information table, and the transmission mode information table with the assigned transmission mode number is stored in advance in storage areas inside the control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d, as well as in storage areas inside the control units 12b and 12d and the control units 71X, 71X-1 to 71X-m, 71aX, 71aX-1 to 71aX-m, 71Y, 71Y-1 to 71Y-n, 71aY, and 71aY-1 to 71aY-n. The reason why the transmission mode information table is also stored in storage areas inside the control units 12b and 12d of the connection node devices 1b and 1d is that the control units 12b and 12d generate a switching instruction signal to be output to the output port switching unit 14a based on the center wavelength included in the transmission mode information.

[0195] The control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d refer to a transmission mode information table stored in an internal storage area to detect a transmission mode number corresponding to a combination of the transmission path characteristics, desired bit rate information, and specification information of the optical transceivers 21X, 21X-1 to 21X-m, 21aX, and 21aX-1 to 21aX-m. The control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d generate transmission mode information including the detected transmission mode number and source address information included in the connection request data.

[0196] When the control units 12b and 12d and the control units 71X, 71X-1 to 71X-m, 71aX, 71aX-1 to 71aX-m, 71Y, 71Y-1 to 71Y-n, 71aY, 71aY-1 to 71aY-n acquire transmission mode information transmitted by the control unit 12 and the transmission path design units 42, 42a, 42b, 42c, and 42d, they refer to a transmission mode information table in an internal storage area and read out configuration information corresponding to the transmission mode number included in the acquired transmission mode information. By using this procedure, the control units 12b and 12d and the control units 71X, 71X-1 to 71X-m, 71aX, 71aX-1 to 71aX-m, 71Y, 71Y-1 to 71Y-n, 71aY, 71aY-1 to 71aY-n may be notified of the transmission mode identified using the transmission mode number.

[0197] In the second and third embodiments and other configuration examples of each embodiment, the transmission path design units 42, 42a, 42b, 42c, and 42d calculate end-to-end transmission path characteristics, i.e., between the connection source and the connection destination, based on the connection information received from the connection node devices 1a, 1b, 1c, 1d, and 1e and the transmission path information of the optical transmission paths 52 and 52-i corresponding to the connection destination address information included in the connection request data.In contrast to this, the following configuration may be used.

[0198] The control units 12a, 12b, 12c, 12d, and 12e of the connecting node devices 1a, 1b, 1c, 1d, and 1e calculate transmission path characteristics based on the connection information of the optical transmission paths 51, 51-1 to 51-m, and transmit the calculated transmission path characteristics to the operation devices 4, 4a, 4b, 4c, and 4d in place of the connection information. The transmission path design units 42, 42a, 42b, 42c, and 42d of the operation devices 4, 4a, 4b, 4c, and 4d calculate the transmission path characteristics of the optical transmission paths 52, 52-i corresponding to the destination address information included in the connection request data, based on the transmission path information of the optical transmission paths 52, 52-1 to 52-n stored in internal storage areas or the transmission path information of the optical transmission paths 52, 52-1 to 52-n obtained on demand. The transmission path design units 42, 42a, 42b, 42c, and 42d may calculate approximate end-to-end transmission path characteristics based on the transmission path characteristics received from the control units 12a, 12b, 12c, 12d, and 12e and the transmission path characteristics calculated based on the transmission path information of the optical transmission paths 52 and 52-i. Note that the transmission path design units 42, 42a, 42b, 42c, and 42d may be configured as follows, instead of calculating the transmission path characteristics of the optical transmission paths 52 and 52-1 to 52-n based on the transmission path information of the optical transmission paths 52 and 52-1 to 52-n. The transmission path design units 42, 42a, 42b, 42c, and 42d calculate the transmission path characteristics of the optical transmission paths 52, 52-1 to 52-n in advance based on the transmission path information of the optical transmission paths 52, 52-1 to 52-n, and store the calculated transmission path characteristics of the optical transmission paths 52, 52-1 to 52-n in advance in an internal storage area. With this configuration, the transmission path design units 42, 42a, 42b, 42c, and 42d can acquire the transmission path characteristics of the optical transmission paths 52, 52-1 to 52-n by reading the transmission path characteristics of the optical transmission paths 52, 52-1 to 52-n from the internal storage area, instead of calculating the transmission path characteristics of the optical transmission paths 52, 52-1 to 52-n.

[0199] In the above-described first to third embodiments and other configuration examples of each embodiment, the output port switching unit 14 includes two optical switch units 15T and 15R, and the output port switching unit 14a includes two optical switch units 15aT and 15aR. In contrast, the output port switching units 14 and 14a may be configured to include a single optical switch unit, and the port setting of the single optical switch unit may be used to separate the port for the sending direction from the port for the receiving direction.

[0200] The output port switching unit 14a described above is assumed to be, for example, a WSS or a Fiber Patch Panel. Alternatively, an arrayed waveguide grating (AWG) may be used as the output port switching unit 14a. For example, an AWG is applied to the output port switching unit 14a of an optical transmission system 102b shown in FIG. 15, and it is predetermined that a wavelength path of 1530 nm or more and less than 1540 nm is output to the connection information processing unit 13b, and a wavelength path of 1540 nm or more and less than 1560 nm is output to the optical transmission path 52. The control unit 12d transmits, to the operation device 4c, information indicating that the connection node device 1d is equipped with an AWG as the output port switching unit 14a and information indicating the wavelength path preset in the AWG, together with connection information and the like. A transmission path design unit 42c of the operation device 4c generates transmission mode information by adding the information indicating that the connection node device 1d is equipped with an AWG and the information indicating the wavelength path preset in the AWG, which are received from the control unit 12d. In this way, by applying an AWG to the output port switching unit 14a, the optical transmitting and receiving units 21aX-1 to 21aX-m can change the wavelength of the tunable wavelength light sources 25aX-1 to 25aX-m that they respectively include in accordance with the transmission mode information, thereby switching from the connection to the connecting node device 1d to the optical transmission path 52. Therefore, the control unit 12d does not need to output a switching instruction signal to the output port switching unit 14a.

[0201] (Fourth embodiment) 17 is a block diagram showing the configuration of an optical transmission system 103 in a fourth embodiment. In the fourth embodiment, the same components as those in the first to third embodiments and other configuration examples of each embodiment are assigned the same reference numerals, and different components will be described below. The optical transmission system 103 includes optical communication devices 2bX and 2bY, connecting node devices 1fX and 1fY, an operation device 4e, an optical transmission line 51 connecting the optical transceiver 21aX of the optical communication device 2bX and the output port switching unit 14aX of the connecting node device 1fX, an optical transmission line 53 connecting the optical transceiver 21aY of the optical communication device 2bY and the output port switching unit 14aY of the connecting node device 1fY, an optical transmission line 52 connecting the output port switching unit 14aX of the connecting node device 1fX and the output port switching unit 14aY of the connecting node device 1fY, a connection line 3X connecting the connecting node device 1fX and the operation device 4e, and a connection line 3Y connecting the connecting node device 1fY and the operation device 4e. Here, the optical transmission line 52 is, for example, an optical transmission line constituting a carrier network owned by a telecommunications carrier, and the optical transmission lines 51 and 53 are, for example, dark fibers. The optical communication devices 2bX and 2bY are, for example, communication devices used by users.

[0202] The optical transceivers 21aX and 21aY included in the optical communication devices 2bX and 2bY have the same configuration as the optical transceiver 21aX-1 of the optical transmission system 102 shown in Fig. 8. Hereinafter, when referring to the functional units included in each of the optical transceivers 21aX and 21aY, the sub-number "X-1" of the reference numeral of each functional unit included in the optical transceiver 21aX-1 will be replaced with "X" and "Y", respectively.

[0203] The output port switching units 14aX and 14aY included in the connecting node devices 1fX and 1fY have the same configuration as the output port switching unit 14a of the connecting node device 1b of the optical transmission system 102 shown in Fig. 8. Hereinafter, when indicating the functional units included in each of the output port switching units 14aX and 14aY, the symbol "a" of each functional unit included in the output port switching unit 14a will be replaced with "aX" and "aY", respectively.

[0204] The connection information processing units 13aX and 13aY have the same configuration as the connection information processing unit 13a of the connection node device 1b of the optical transmission system 102 shown in Fig. 8. Hereinafter, when referring to the functional units provided in each of the connection information processing units 13aX and 13aY, the sub-number "a" of the symbol of each functional unit provided in the connection information processing unit 13a will be replaced with "aX" and "aY", respectively.

[0205] The control units 12fX and 12fY included in the connecting node devices 1fX and 1fY have the following configuration in addition to the configuration included in the control unit 12b of the connecting node device 1b of the optical transmission system 102 shown in FIG. 8. Identification information identifying each of the connecting node devices 1fX and 1fY is previously assigned to each of the connecting node devices 1fX and 1fY. The control unit 12fX stores the identification information identifying the connecting node device 1fX in an internal storage area beforehand. When transmitting connection information and connection request data to the operation device 4e, the control unit 12fX adds the identification information identifying the connecting node device 1fX stored in the internal storage area and transmits the data to the operation device 4e. Similarly, the control unit 12fY stores the identification information identifying the connecting node device 1fY in an internal storage area beforehand. When transmitting connection information and connection request data to the operation device 4e, the control unit 12fY adds the identification information identifying the connecting node device 1fY stored in the internal storage area and transmits the data to the operation device 4e.

[0206] The operation device 4e includes a route detection unit 41 and a transmission path design unit 42e. The transmission path design unit 42e stores transmission path information of the optical transmission path 52 in advance in an internal storage area in association with identification information that specifies the optical transmission path 52. The transmission path design unit 42e may calculate the transmission path information of the optical transmission path 52 in advance by a predetermined calculation based on the optical signal transmitted by the optical transmission path 52 and store it in an internal storage area, or may obtain the transmission path information from an external device on demand at a specific timing, such as when laying a network. The transmission path information of the optical transmission path 52 may also be obtained in advance by a method other than the predetermined calculation.

[0207] The transmission path design unit 42e stores in advance in an internal storage area information indicating available resources of the optical transmission path 52. Here, the information indicating available resources is, for example, information indicating wavelengths, wavelength bands, or optical transmission paths that are not used for communication when determining the availability of resources. Note that the information indicating available resources stored in the internal storage area of ​​the transmission path design unit 42e is updated by the transmission path design unit 42e every time a communication path is established. The transmission path design unit 42e stores in advance in an internal storage area a connection line table that associates identification information identifying the connection node device 1fX with the connection line 3X and associates information identifying the connection node device 1fY with the connection line 3Y.

[0208] The transmission path design unit 42e stores a connection status table 43 shown in Fig. 18 in an internal storage area. The record format of the connection status table 43 has the following fields: "request source address information," "connection destination address information," "connection node device," "connection destination optical transmission path," and "received data." The "request source address information" field contains the connection source address information included in the connection request data. The "connection destination address information" field contains the connection destination address information included in the connection request data.

[0209] The "connecting node device" field contains identification information for identifying the connecting node devices 1fX, 1fY that the transmission path design unit 42e receives together with the connection request data. The "destination optical transmission path" field contains identification information for identifying the optical transmission path 52 that corresponds to the destination address information included in the connection request data detected by the route detection unit 41. The "received data" field contains the connection information and connection request data received by the transmission path design unit 42e.

[0210] To connect the optical transceiver 21aX and the optical transceiver 21aY, the transmission path design unit 42e refers to the connection status table 43 and calculates the transmission path characteristics of the optical transmission path from the optical transmission path 51 to the optical transmission path 53 via the optical transmission path 52. The transmission path design unit 42e identifies the transmission mode to be applied to the optical transmitters 24aX and 24aY based on the calculated transmission path characteristics.

[0211] (Processing of the optical transmission system of the fourth embodiment) Next, processing by the optical transmission system 103 of the fourth embodiment will be described with reference to Fig. 19 and Fig. 20. Fig. 19 is a flowchart showing the flow of processing by the optical transmission system 103 of the fourth embodiment. In an initial state, the output port switching unit 14aX of the connecting node device 1fX connects the wavelength path of the fundamental wavelength of the optical transmission line 51 to the connection information processing unit 13aX of the edge function unit 11fX of the connecting node device 1fX. In an initial state, the output port switching unit 14aY of the connecting node device 1fY connects the wavelength path of the fundamental wavelength of the optical transmission line 53 to the connection information processing unit 13aY of the edge function unit 11fY of the connecting node device 1fY.

[0212] The following describes the process in which the optical transceiver 21aX provided in the optical communication device 2bX connects to the optical transceiver 21aY of the optical communication device 2bY as its connection destination, and the optical transceiver 21aY provided in the optical communication device 2bY connects to the optical transceiver 21aX of the optical communication device 2bX as its connection destination.

[0213] The control unit 20X of the optical communication device 2bX generates a connection request instruction signal including address information of the optical transceiver 21aY and a desired bit rate to connect to the optical transceiver 21aY included in the optical communication device 2bY. The control unit 20X outputs the generated connection request instruction signal to the control unit 71aX of the optical transceiver 21aX. The control unit 71aX receives the connection request signal output by the control unit 20X and sets the address information of the optical transceiver 21aY included in the received connection request signal as a destination address. The control unit 71aX sets the address information of the optical transceiver 21aX stored in an internal storage area as source address information. The control unit 71aX generates connection request data including the destination address information, the source address information, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21aX stored in an internal storage area. Thereafter, the same process as step Sb2 in FIG. 10 is performed by the optical transceiver 21aX of the optical communication device 2bX (step Sc1-1).

[0214] The control unit 20Y of the optical communication device 2bY generates a connection request instruction signal including address information of the optical transceiver 21aX and a desired bit rate to connect to the optical transceiver 21aX included in the optical communication device 2bX. The control unit 20Y outputs the generated connection request instruction signal to the control unit 71aY of the optical transceiver 21aY. The control unit 71aY receives the connection request signal output by the control unit 20Y and sets the address information of the optical transceiver 21aX included in the received connection request signal as a destination address. The control unit 71aY sets the address information of the optical transceiver 21aY stored in an internal storage area as source address information. The control unit 71aY generates connection request data including the destination address information, the source address information, the desired bit rate included in the connection request instruction signal, and specification information of the optical transceiver 21aY stored in an internal storage area. Thereafter, the same process as step Sb2 in FIG. 10 is performed by the optical transceiver 21aY of the optical communication device 2bY (step Sc1-2).

[0215] In step Sc2-1, the same processing as in step Sb3 in Fig. 10 is performed in the output port switching unit 14aX and connection information processing unit 13aX of the connecting node device 1fX. Here, the transmission path information calculated by the connection information generation unit 38aX of the connecting node device 1fX is transmission path information of the optical transmission path 51, and the connection information generation unit 38aX generates connection information for the optical transmission path 51. In step Sc2-2, the same processing as in step Sb3 in Fig. 10 is performed in the output port switching unit 14aY and connection information processing unit 13aY of the connecting node device 1fY. Here, the transmission path information calculated by the connection information generation unit 38aY of the connecting node device 1fY is transmission path information of the optical transmission path 53, and the connection information generation unit 38aY generates connection information for the optical transmission path 53.

[0216] The control unit 12fX receives the connection information of the optical transmission path 51 and the connection request data output by the connection information generation unit 38aX. The control unit 12fX transmits the received connection information of the optical transmission path 51, the received connection request data, and identification information for identifying the connecting node device 1fX stored in an internal storage area to the operation device 4e via the connection line 3X (step Sc3-1). The control unit 12fY receives the connection information of the optical transmission path 53 and the connection request data output by the connection information generation unit 38aY. The control unit 12fY transmits the received connection information of the optical transmission path 53, the received connection request data, and identification information for identifying the connecting node device 1fY stored in an internal storage area to the operation device 4e via the connection line 3Y (step Sc3-2).

[0217] The operation device 4e performs a transmission mode identification process (step Sc4). Fig. 20 is a flowchart showing the processing flow of the subroutine of the transmission mode identification process. Below, we will explain the processing when the operation device 4e receives the connection information of the optical transmission path 51, the connection request data, and the identification information that identifies the connecting node device 1fX, transmitted by the control unit 12fX of the connecting node device 1fX after the processing of step Sc3-1.

[0218] The route detection unit 41 of the operation device 4e receives connection request data transmitted by the control unit 12fX of the connecting node device 1fX and identification information identifying the connecting node device 1fX. The route detection unit 41 refers to a route information table stored in an internal storage area or a route information table obtained on demand, and detects connection destination address information included in the received connection request data, in this case, identification information identifying the optical transmission path 52 corresponding to the address information of the optical transceiver 21aY. The route detection unit 41 outputs the detected identification information identifying the optical transmission path 52 and the received identification information identifying the connecting node device 1fX to the transmission path design unit 42e.

[0219] The transmission path design unit 42e receives connection information of the optical transmission path 51, connection request data, and identification information identifying the connecting node device 1fX, which are transmitted by the control unit 12fX of the connecting node device 1fX. The transmission path design unit 42e takes in the identification information identifying the optical transmission path 52 and the identification information identifying the connecting node device 1fX, which are output by the path detection unit 41. In this case, the combination of the connection information of the optical transmission path 51, connection request data, and identification information identifying the connecting node device 1fX received by the transmission path design unit 42e from the control unit 12fX of the connecting node device 1fX matches the combination of the identification information identifying the optical transmission path 52 and the identification information identifying the connecting node device 1fX taken in by the transmission path design unit 42e as the output of the path detection unit 41, in terms of the identification information identifying the connecting node device 1fX. Therefore, the transmission path design unit 42e assumes that these combinations correspond to each other and performs the following processing based on the connection information of the optical transmission path 51, the connection request data, the identification information that identifies the optical transmission path 52, and the identification information that identifies the connection node device 1fX.

[0220] The transmission path design unit 42e creates a new record in the connection status table 43 stored in an internal storage area. The transmission path design unit 42e writes the connection source address information included in the received connection request data, in this case the address information of the optical transceiver 21aX, in the "request source address information" field of the created record. The transmission path design unit 42e writes the connection destination address information included in the received connection request data, in this case the address information of the optical transceiver 21aY, in the "destination address information" field of the record.

[0221] The transmission path design unit 42e writes, in the "connecting node device" field of the record, identification information that identifies the received connecting node device 1fX. The transmission path design unit 42e writes, in the "destination optical transmission path" field of the record, identification information that identifies the optical transmission path 52 that was taken in as an output of the route detection unit 41. The transmission path design unit 42e writes, in the "received data" field of the record, the connection information of the received optical transmission path 51 and the connection request data.

[0222] 19 is completed before the processing of step Sd1 caused by the processing of step Sc3-2, a record related to the optical transceiver 21aY of the optical communication device 2bY will not be generated in the connection status table 43 of the transmission path design unit 42e at the time when the processing of step Sd1 caused by the processing of step Sc3-1 is completed. On the other hand, if the processing of step Sd1 caused by the processing of step Sc3-2 is completed before the processing of step Sd1 caused by the processing of step Sc3-1, a record related to the optical transceiver 21aY of the optical communication device 2bY will be generated in the connection status table 43 of the transmission path design unit 42e at the time when the processing of step Sd1 caused by the processing of step Sc3-1 is completed.

[0223] To determine which of these states exists, the transmission path design unit 42e refers to the connection state table 43, determines whether or not there is a record in which the address information of the optical transceiver 21aY written in the "destination address information" field of the newly created record is written in the "request source address information" field, and adds "1" to the value of a processing count counter provided in an internal storage area. However, the initial value of the processing count counter is "0" (step Sd2).

[0224] The transmission path design unit 42e determines that there is no record in which the address information of the optical transceiver 21aY written in the "destination address information" field of the newly created record is written in the "request source address information" field (step Sd2, No). In this case, the processing of step Sd1, which is executed due to step Sc3-2, has not been completed. Therefore, the transmission path design unit 42e waits for a certain period of time until a record related to the optical transceiver 21aY of the optical communication device 2bY is created in the connection status table 43 (step Sd3).

[0225] If the transmission path design unit 42e determines that there is a record in which the address information of the optical transceiver 21aY written in the "destination address information" field of the newly created record is written in the "request source address information" field (step Sd2, Yes), it determines whether the value of the counter for the number of processing times stored in the internal memory area is "2" or greater (step Sd4).

[0226] The reason for performing the determination process of step Sd4 is to stop one of the transmission mode determination processes, which is performed in step Sc4 for the optical transceiver 21aX of the optical communication device 2bX after the process of step Sc3-1 and the transmission mode determination process of step Sc4 for the optical transceiver 21aY of the optical communication device 2bY after the process of step Sc3-2, so that they are not executed in parallel. If the value of the processing count counter is "1," this means that the determination process of step Sd2 has been performed only once, and at the time of that determination process, a record has already been generated in the connection status table 43 by the process of step Sd1 of the preceding transmission mode determination process. Therefore, in this case, the preceding transmission mode determination process is given priority, and the subsequent transmission mode determination process is stopped.

[0227] If the transmission path design unit 42e determines that the counter value for the number of processing times stored in the internal storage area is not "2" or more (step Sd4, No), the transmission path design unit 42e ends the process. On the other hand, if the transmission path design unit 42e determines that the counter value for the number of processing times stored in the internal storage area is "2" or more (step Sd4, Yes), the transmission path design unit 42e performs the following determination process.

[0228] The transmission path design unit 42e determines whether or not the connection conditions are satisfied for two records of the connection targets stored in the connection status table 43, i.e., a record in which the address information of the optical transceiver 21aX is written in the "request source address information" field and a record in which the address information of the optical transceiver 21aY written in the "connection destination address information" field of the record is written in the "request source address information" field of the record (step Sd5). Here, the connection conditions mean, for example, that in the two records of the connection targets stored in the connection status table 43, the address information written in the "request source address information" field of one of the records matches the address information written in the "connection destination address information" field of the other record, and the contents of the "connection destination optical transmission path" field match.

[0229] Here, the address information of the optical transceiver 21aY is written in the "connection destination address information" field of the record whose "request source address information" field is the address information of the optical transceiver 21aX. The address information of the optical transceiver 21aX is written in the "connection destination address information" field of the record whose "request source address information" field is the address information of the optical transceiver 21aY. Therefore, the first connection condition, that the address information written in one "request source address information" field matches the address information written in the other "connection destination address information" field, is satisfied. The "connection destination optical transmission path" field of the record whose "request source address information" field is the address information of the optical transceiver 21aX has been written in the "connection destination optical transmission path" field, and the "request source address information" field of the record whose "request source address information" is the address information of the optical transceiver 21aY has been written in the "connection destination optical transmission path" field. Therefore, the second connection condition, that the contents of the "connection destination optical transmission path" fields match, is also satisfied.

[0230] Therefore, the transmission path design unit 42e determines that the connection conditions are met (step Sd5, Yes). The transmission path design unit 42e reads connection information for the optical transmission path 51 from the "received data" item of the record in which the "request source address information" is the address information of the optical transceiver 21aX. The transmission path design unit 42e reads connection information for the optical transmission path 53 from the "received data" item of the record in which the "request source address information" is the address information of the optical transceiver 21aY.

[0231] The transmission path design unit 42e reads and acquires the transmission path information of the optical transmission path 52 from an internal storage area, or acquires on-demand the transmission path information of the optical transmission path 52. Based on the read connection information of the optical transmission path 51 and the connection information of the optical transmission path 53 and the acquired transmission path information of the optical transmission path 52, the transmission path design unit 42e calculates the transmission path characteristics using, for example, an internal transmission design tool such as GNPy (step Sd6).

[0232] The transmission path design unit 42e selects configuration information by a predetermined selection process based on the calculated transmission path characteristics, information indicating available resources of the optical transmission path 52 corresponding to the destination address information detected by the route detection unit 41 and stored in an internal storage area, and the desired bit rate information and specification information of the optical transceivers 21aX and 21aY included in the connection request data written in the "received data" field of the record whose "request source address information" field is the address information of the optical transceiver 21aX and the record whose "request source address information" field is the address information of the optical transceiver 21aY. The transmission path design unit 42e generates transmission mode information including the selected configuration information and the destination address information included in the connection request data (step Sd7), and returns to the processing of the flowchart shown in FIG.

[0233] On the other hand, if it is determined that the connection conditions are not satisfied (No in step Sd5), the transmission path design unit 42e notifies the outside that connection is not possible and ends the process.

[0234] The transmission path design unit 42e refers to the connection line table stored in an internal storage area, and transmits the generated transmission mode information and identification information for specifying the optical transmission path 52 detected by the path detection unit 41 to the control unit 12fX of the connecting node apparatus 1fX through the connection line 3X (step Sc5-1). The transmission path design unit 42e refers to the connection line table stored in an internal storage area, and transmits the generated transmission mode information and identification information for specifying the optical transmission path 52 detected by the path detection unit 41 to the control unit 12fY of the connecting node apparatus 1fY through the connection line 3Y (step Sc5-2). The processing order of steps Sc5-1 and Sc5-2 may be performed in parallel, or may be steps Sc5-1 and Sc5-2 in that order, or may be reversed.

[0235] 10 is performed in the edge function unit 11fX and the output port switching unit 14aX (step Sc6-1), and the same process as step Sb10 is performed in the optical transceiver 21aX of the optical communication device 2bX (step Sc7-1). In the connection node device 1fY, the same process as step Sb9-2 of FIG. 10 is performed in the edge function unit 11fY and the output port switching unit 14aY (step Sc6-2), and the same process as step Sb10 is performed in the optical transceiver 21aY of the optical communication device 2bY (step Sc7-2).

[0236] 10, i.e., performs a switching process to connect the wavelength route of the optical transmission path 52 corresponding to the received identification information for identifying the optical transmission path 52 and having the center wavelength specified in the transmission mode information to the wavelength route of the optical transmission path 51 and having the center wavelength specified in the transmission mode information (step Sc8-1).The control unit 12fY of the connecting node device 1fY performs a switching process to connect the wavelength route of the optical transmission path 52 corresponding to the received identification information for identifying the optical transmission path 52 and having the center wavelength specified in the transmission mode information to the wavelength route of the optical transmission path 53 and having the center wavelength specified in the transmission mode information (step Sc8-2). As a result, the optical transceiver 21aX and the optical transceiver 21aY are connected by a wavelength path included in each of the optical transmission paths 51, 52, and 53, and having a center wavelength specified in the transmission mode information.

[0237] Regarding the timing at which steps Sc8-1 and Sc8-2 are performed, any of the following methods may be applied: a method of performing steps Sc8-1 and Sc8-2 after the above-mentioned pre-measured time has elapsed; a method of performing steps Sc8-1 and Sc8-2 when information indicating that reception of transmission mode information has been completed is received; or a method of performing steps Sc8-1 and Sc8-2 when notification is received that optical output in basic mode has stopped.

[0238] In the optical transmission system 103, the configuration of the transmission mode information table described above may be applied, or a configuration may be applied in which the transmission mode identified by the transmission mode number is notified to the optical transceivers 21aX, 21aY and the control units 12fX, 12fY of the connecting node devices 1fX, 1fY.

[0239] In the configuration of the fourth embodiment, the operation device 4e is connected to the connecting node device 1fX and the connecting node device 1fY, and reads and acquires transmission path information of the optical transmission path 52, which is the second optical transmission path, from an internal storage area that has been stored in advance, or acquires the transmission path information of the optical transmission path 52 on demand, and combines the acquired transmission path information of the optical transmission path 52 with connection information of the optical transmission path 51, which is the first optical transmission path, acquired by a connection information processing unit 13aX of the connecting node device 1fX from an optical signal transmitted by an optical transmitting / receiving unit 21aX included in the optical communication device 2bX, which is the first optical communication device. The optical communication device 1fY identifies a transmission mode based on the connection request data transmitted by the optical transmitter / receiver 21aX included in the optical communication device 2bX in an optical signal, the connection information of the optical transmission path 53, which is the third optical transmission path, obtained by the connection information processing unit 13aY of the connecting node device 1fY from the optical signal transmitted by the optical transmitter / receiver 21aY included in the optical communication device 2bY, which is the second optical communication device, and the connection request data transmitted by the optical transmitter / receiver 21aY included in the optical communication device 2bY in an optical signal, and transmits transmission mode information indicating the identified transmission mode to the control unit 12fX of the connecting node device 1fX and the control unit 12fY of the connecting node device 1fY. The output port switching unit 14aX of the connecting node device 1fX performs switching processing after the control unit 12fX transmits transmission mode information to the optical transceiver 21aX through the optical transmission path 51, and the output port switching unit 14aY of the connecting node device 1fY performs switching processing after the control unit 12fY transmits the transmission mode information to the optical transceiver 21aY of the optical communication device 2bY through the optical transmission path 53. This connects the optical transceiver 21aX included in the optical communication device 2bX to the optical transceiver 21aY included in the optical communication device 2bY through the optical transmission path 51, the optical transmission path 52, and the optical transmission path 53. The optical transceiver 21aX included in the optical communication device 2bX receives transmission mode information that the control unit 12fX of the connecting node device 1fX receives from the operation device 4e and sends to the optical transmission path 51, and transmits and receives optical signals through the optical transmission path 51 in the transmission mode indicated by the received transmission mode information.The optical transceiver 21aY included in the optical communication device 2bY receives transmission mode information that the control unit 12fY of the connecting node device 1fY receives from the operation device 4e and sends to the optical transmission path 53, and transmits and receives optical signals through the optical transmission path 53 in the transmission mode indicated by the received transmission mode information. As a result, when connecting the optical transceivers 21aX and 21aY included in the optical communication devices 2bX and 2bY via the multiple optical transmission paths 51, 52, and 53, connection can be made without human intervention using an optical path of the optimal transmission mode. Therefore, it is possible to reduce the cost and time required to set up an optical path.

[0240] In step Sd8 shown in FIG. 20 of the fourth embodiment, in addition to notifying the outside that connection is not possible, the optical transceiver 21aX of the optical communication device 2bX and the optical transceiver 21aY of the optical communication device 2bY may be notified of the inability to connect via the wavelength path of the fundamental wavelength.

[0241] (Another configuration example (part 1) of the fourth embodiment) The optical transmission system 103 of the above-described fourth embodiment includes two connection node devices 1fX and 1fY, but may include a greater number of connection node devices with the same configuration (hereinafter, these will be referred to as connection node devices 1f-1 to 1f-k, and connection lines connected to the connection node devices 1f-1 to 1f-k will be referred to as connection lines 3-1 to 3-k, where k is an integer equal to or greater than 3). A plurality of optical transceivers, which are functional units with the same configuration as the optical transceivers 21aX and 21aY, are connected to each of the connection node devices 1f-1 to 1f-k in the form shown in the second and third embodiments and other configuration examples of each embodiment, for example. In this case, the transmission path design unit 42e of the operation device 4e receives, for example, connection information of the optical transmission path to which the connecting node device 1f-1 is connected, transmitted by the control unit 12f-1 of the connecting node device 1f-1, connection request data requesting connection to an optical transceiver provided in an optical communication device connected to one of the connecting node devices 1f-2 to 1f-k, and identification information that identifies the connecting node device 1fX-1.

[0242] The transmission path design unit 42e starts the transmission mode specification process of step Sc4 in Fig. 19, and if a record related to the optical transceiver unit included in the optical communication device to be the connection destination is not generated in the connection status table 43, the transmission path design unit 42e waits for a certain period of time as shown in the process of step Sd3 in Fig. 20. If a record related to the optical transceiver unit included in the optical communication device to be the connection destination is not generated in the connection status table 43 even after waiting for a certain period of time, it is assumed that the connecting node devices 1f-2 to 1f-k have failed to transmit connection information, etc. In preparation for such a case, the transmission path design unit 42e of the operation device 4e may transmit a trigger signal for causing the connecting node devices 1f-2 to 1f-k to transmit connection information, etc. to all connecting node devices 1f-2 to 1f-k other than the connecting node device 1f-1 through connection lines connected to each of the connecting node devices 1f-2 to 1f-k, thereby causing the connecting node devices 1f-2 to 1f-k to resend the connection information, etc.

[0243] (Another configuration example (part 2) of the fourth embodiment) For example, suppose that the optical transceiver 21aX of the optical communication device 2bX of the fourth embodiment transmits connection request data to the optical transceiver 21aY of the optical communication device 2bY as the connection destination, causing the control unit 12fY of the connecting node device 1fY to receive a trigger signal for retransmitting the connection information and the like transmitted by the transmission path design unit 42e of the operation device 4e. The control unit 12fY transmits a transmission path information acquisition instruction signal for causing all optical communication devices connected to the connecting node device 1fY in the basic mode to acquire transmission path information, by communication in the basic mode. Here, the following description will be given assuming that only one optical communication device, 2bY, is connected to the connecting node device 1fY, as shown in FIG. 17.

[0244] The optical receiver 28Y of the optical receiver 27Y of the optical transmitter / receiver 21aY included in the optical communication device 2bY receives an optical signal including a transmission path information acquisition instruction signal transmitted through the optical transmission path 53, converts the received optical signal into an electrical reception data signal, and outputs the electrical reception data signal to the digital signal processor 23aY. The digital signal processor 23aY receives the reception data signal output by the optical receiver 28Y, reads the transmission path information acquisition instruction signal from the received data signal, and outputs the read transmission path information acquisition instruction signal to the controller 71aY. Upon receiving the transmission path information acquisition instruction signal output by the digital signal processor 23aY, the controller 71aY obtains information about the optical transmission path 53 from the reception data signal received by the digital signal processor 23aY. Here, the information about the optical transmission path 53 may be transmission path information about the optical transmission path 53 calculated by the controller 71aY through a predetermined calculation based on the reception data signal received by the digital signal processor 23aY, or may be information required for calculating the transmission path information about the optical transmission path 53.

[0245] The control unit 71aY outputs the acquired information about the optical transmission path 53 to the digital signal processing unit 23aY to transmit it to the connecting node device 1fY. When the control unit 71aY has connection request data for which connection is on hold, the control unit 71aY outputs the connection request data again to the digital signal processing unit 23aY together with the calculated transmission path information of the optical transmission path 53.

[0246] In this case, the connection information generating unit 38aY of the connecting node device 1fY can acquire the connection information of the optical transmission path 53 based on the information about the optical transmission path 53 transmitted by the optical communication device 2bY, instead of performing a process of calculating the transmission path information of the optical transmission path 53. More specifically, when the information about the optical transmission path 53 is the transmission path information of the optical transmission path 53, the connection information generating unit 38aY can acquire the transmission path information of the optical transmission path 53 without performing a process of calculating the transmission path information of the optical transmission path 53. When the information about the optical transmission path 53 is information necessary for calculating the transmission path information of the optical transmission path 53, the connection information generating unit 38aY can acquire the transmission path information of the optical transmission path 53 by calculating the transmission path information of the optical transmission path 53 by a predetermined calculation based on the information.

[0247] Furthermore, when the connection destination address information included in the connection request data newly transmitted by the control unit 71aY of the optical transceiver 21aY is the address information of the optical transceiver 21aX of the optical communication device 2bX, it becomes possible to connect the optical transceiver 21aX and the optical transceiver 21aY in response to a trigger signal. As a result, in the processing of step Sd3 of Fig. 20, the transmission path design unit 42e of the operation device 4e does not wait for a certain period of time, but by transmitting a trigger signal, it becomes possible to actively obtain transmission path information of the optical transmission path 53 and the connection request data from the optical transceiver 21aY of the optical communication device 2bY and connect the optical transceiver 21aX and the optical transceiver 21aY.

[0248] The transmission path information of the optical transmission path 53 calculated by the control unit 71aY of the optical transceiver 21aY and the transmission path information of the optical transmission path 53 calculated by the connection information generator 38aY of the connecting node device 1fY through a predetermined calculation based on information required for calculating the transmission path information of the optical transmission path 53 are transmission path information of the optical transmission path 53 in the direction from the connecting node device 1fY to the optical communication device 2bY. In contrast, the transmission path information of the optical transmission path 53 calculated by the connection information generator 38aY of the connecting node device 1fY in the fourth embodiment is transmission path information of the optical transmission path 53 in the direction from the optical communication device 2bY to the connecting node device 1fY. The characteristics of the optical fiber 53T and the optical fiber 53R included in the optical transmission path 53 can generally be considered to be similar. Therefore, regardless of the transmission path information of either optical transmission path 53, similar transmission path characteristics can be calculated and similar transmission modes can be identified.

[0249] The control unit 12fY of the connecting node device 1fY may transmit a transmission path information acquisition instruction signal to an optical transmitting and receiving unit included in the newly connected optical communication device. The transmission path information acquisition instruction signal and information related to the optical transmission path 53 acquired by the control unit 71aY of the connecting node device 1fY may be transmitted in an empty area in the overhead of the transmission frame, or in the communication channel or payload area of ​​the transmission frame. In the first to fourth embodiments and other configuration examples of each embodiment, when acquiring the transmission path information of the optical transmission path 51, 51-1 to 51-m, the above-mentioned means for acquiring the transmission path information of the optical transmission path 53, i.e., means for calculating the transmission path information of the optical fiber 51R, 51R-1 to 51R-m may be applied instead of calculating the transmission path information of the optical fiber 51T, 51T-1 to 51T-m included in the optical transmission path 51, 51-1 to 51-m.

[0250] In the fourth embodiment, instead of the optical communication devices 2bX and 2bY, an optical communication device 2X having an optical transceiver 21X with a single-wavelength light source 25X and an optical communication device 2Y having an optical transceiver 21Y with a single-wavelength light source 25Y may be connected to the connection node devices 1fX and 1fY, respectively.

[0251] In the first to fourth embodiments, the connection request data and the transmission mode information are transmitted using the free space in the overhead area of ​​the transmission frame. However, the connection request data and the transmission mode information may be transmitted via the communication channel of the transmission frame or via the payload area of ​​the transmission frame.

[0252] In the first to fourth embodiments described above, the connection information including the BER is generated, but the connection information not including the BER may be generated.

[0253] In the third and fourth embodiments, the optical input information is transmitted using a communication channel. Alternatively, the optical input information may be transmitted using a GCC (General Communication Channel) in the frame header.

[0254] In the above-described first and second embodiments, since there is only one optical transceiver 21X that transmits connection request data, the control unit 12 and the transmission path design unit 42 of the operation device 4 do not need to include the connection source address information included in the connection request data when generating transmission mode information. In the fourth embodiment, since one optical transceiver 21aX and one optical transceiver 21aY are connected to each of the connecting node devices 1fX and 1fY, the operation device 4e also does not need to include the connection source address information included in the connection request data when generating transmission mode information. In the third embodiment, even when m=1, there is no need to include the connection source address information included in the connection request data when generating transmission mode information. When the transmission mode information does not include the connection source address information, the control units 71X, 71Y, 71aX, 71aY, 71X-1, 71Y-1, 71aX-1, 71aY-1 of the optical transceivers 21X, 21Y, 21aX, 21aY, 21X-1, 21Y-1, 21aX-1, 21aY-1 determine the transmission mode information output from the digital signal processors 23X, 23Y, 23aX, 23aY, 23X-1, 23Y-1, 23aX-1, 23aY-1. When mode information is imported, there is no need to determine whether the imported transmission mode information includes address information assigned to the optical transceiver units 21X, 21Y, 21aX, 21aY, 21X-1, 21Y-1, 21aX-1, 21aY-1 that the unit itself has stored in an internal memory area, and the imported transmission mode information can be used as transmission mode information corresponding to the connection request data that the unit itself has generated.

[0255] In the above-described first to fourth embodiments and other configuration examples, the fundamental output optical power in the fundamental mode may not be predetermined. In this case, when transmitting an optical signal in the fundamental mode, the single-wavelength light sources 25X, 25Y, 25X-1 to 25X-m, 25Y-1 to 25Y-m and the tunable wavelength light sources 25aX, 25aY, 25aX-1 to 25aX-m, 25aY-1 to 25aY-m generate an optical signal with an output optical power of an initial value.

[0256] The transmission path design unit 42e of the fourth embodiment calculates the end-to-end transmission path characteristics, i.e., between the connection source and the connection destination, based on the connection information received from each of the connecting node devices 1fX and 1fY and the transmission path information of the optical transmission path 52 corresponding to the connection destination address information included in the connection request data. Alternatively, the following configuration may be adopted.

[0257] The control units 12fX and 12fY of the connecting node devices 1fX and 1fY each calculate transmission path characteristics based on the connection information of the optical transmission paths 51 and 53, and transmit the calculated transmission path characteristics to the operation device 4e in place of the connection information. A transmission path design unit 42e of the operation device 4e calculates the transmission path characteristics of the optical transmission path 52 based on the transmission path information of the optical transmission path 52 stored in an internal storage area. The transmission path design unit 42e may calculate approximate end-to-end transmission path characteristics based on the transmission path characteristics of the optical transmission path 51 and the transmission path characteristics of the optical transmission path 53 transmitted by the control units 12fX and 12fY, and the transmission path characteristics of the optical transmission path 52 calculated based on the transmission path information of the optical transmission path 52. The transmission path design unit 42e may calculate the transmission path characteristics of the optical transmission path 52 based on the transmission path information of the optical transmission path 52 in advance, rather than calculating the transmission path characteristics of the optical transmission path 52 based on the transmission path information of the optical transmission path 52, and store the calculated transmission path characteristics of the optical transmission path 52 in an internal storage area in advance, and read out the transmission path characteristics of the optical transmission path 52 from the internal storage area instead of performing the process of calculating the transmission path characteristics of the optical transmission path 52.

[0258] The above-described first to fourth embodiments and other configuration examples of each embodiment may also be configured as follows. For example, the connection information generation units 38, 38a, 38aX included in the connecting node devices 1, 1a, 1b, 1c, 1d, 1e, 1fX calculate the transmission path information of the optical transmission path 51 multiple times. In the fourth embodiment, the connection information generation unit 38aY included in the connecting node device 1fY further calculates the transmission path information of the optical transmission path 53 multiple times. The control unit 12 and the transmission path design units 42, 42a, 42b, 42c, 42d, 42e acquire all of the transmission path information calculated multiple times as described above by the connection information generation units 38, 38a, 38aX, 38aY. The control unit 12 and the transmission path design units 42, 42a, 42b, 42c, 42d, and 42e calculate a plurality of transmission path characteristics corresponding to each of the acquired plurality of pieces of transmission path information, and identify a plurality of transmission modes corresponding to each of the calculated plurality of transmission path characteristics. The control unit 12 and the transmission path design units 42, 42a, 42b, 42c, 42d, and 42e may select one transmission mode from the identified plurality of transmission modes by majority vote, that is, select the transmission mode with the largest number of types among the plurality of transmission modes, and set the selected transmission mode as the final transmission mode.

[0259] In the above-described first to fourth embodiments and other configuration examples of each embodiment, in the case of the connection node apparatuses 1, 1a, 1c, 1e, 1fX, 1fY, instead of the single wavelength light sources 36, 36X, 36Y provided in the connection information processing units 13, 13a, 13aX, 13aY, for example, a wavelength-tunable light source similar to the wavelength-tunable light source 25aX, in which the wavelength of the continuous light generated is predetermined to be the fundamental wavelength, may be applied. When the subsequent information processing units 13, 13a, 13aX, 13aY are provided in the connecting node devices 1, 1a, 1b, 1c, 1d, 1e, 1fX, 1fY, the control units 12, 12a, 12b, 12c, 12e, 12fX, 12fY of the connecting node devices 1, 1a, 1b, 1c, 1e, 1fX, 1fY may output a wavelength designation signal that designates a fundamental wavelength to the wavelength-tunable light source, thereby setting the wavelength of the wavelength-tunable light source to the fundamental wavelength. Similarly, instead of the single wavelength light sources 25X, 25X-1 to 25X-m, 25Y, 25Y-1 to 25Y-n provided in the optical transmission / reception units 21X, 21X-1 to 21X-m, 21Y, 21Y-1 to 21Y-n, a wavelength tunable light source similar to the wavelength tunable light source 25aX, in which the wavelength of the continuous light generated is predetermined as the fundamental wavelength, may be applied, or the optical transmission / reception units 21X, 21X-1 to 21X-m, 21Y, 21Y-1 to 21Y-n may be configured to transmit the continuous light to the optical communication devices 2X, 2X At the timing provided in the optical communication devices 2X, 2X-1 to 2X-m, 2Y, 2cY, and 2Y-1 to 2Y-n, the control units 20X, 20X-1 to 20X-m, 20Y, 20aY, and 20Y-1 to 20Y-n may output a wavelength designation signal that designates a fundamental wavelength to the wavelength-tunable light source via the control units 71X, 71X-1 to 71X-m, 71Y, and 71Y-1 to 71Y-n, thereby setting the wavelength of the wavelength-tunable light source to the fundamental wavelength.

[0260] In the above-described first to fourth embodiments and other configuration examples of each embodiment, the control units 71X, 71X-1 to 71X-m, 71aX-1 to 71aX-m, 71aX, and 71aY generate connection request data. In contrast to this, the control units 20X, 20aX, 20X-1 to 20X-m, 20Y may store address information assigned to the optical transceivers 21X, 21X-1 to 21X-m, 21aX-1 to 21aX-m, 21aX, 21aY connected to each other in an internal storage area, generate connection request data instead of a connection request instruction signal, and output the generated connection request data to the control units 71X, 71X-1 to 71X-m, 71aX-1 to 71aX-m, 71aX, 71aY provided in the optical transceiver units 21X, 21X-1 to 21X-m, 21aX-1 to 21aX-m, 21aX, 21aY that are the connection source. In this case, the control units 71X, 71X-1 to 71X-m, 71aX-1 to 71aX-m, 71aX, and 71aY simply import the connection request data output by the control units 20X, 20aX, 20X-1 to 20X-m, and 20Y and output the imported connection request data, eliminating the need to generate connection request data.

[0261] In the first to fourth embodiments and other configuration examples of each embodiment, the connection information generation units 38, 38a, 38aX, and 38aY may be implemented as follows. For example, in the case of the connection node apparatus 1 of the first embodiment, the IF unit 31, optical receiving unit 33, optical transmitting unit 35, and digital signal processing unit 32 of the connection information processing unit 13 may be configured to be inserted into the main body of the connection node apparatus 1 as a single hardware package. In this case, the connection information generation unit 38 and the control unit 12 may be functional units generated by executing a computer program in a central processing unit (CPU) of the main body of the connection node apparatus 1. A CPU may also be provided in the hardware package including the IF unit 31, optical receiving unit 33, optical transmitting unit 35, and digital signal processing unit 32, and the functional unit of the connection information generation unit 38 may be generated by executing a computer program in the CPU of the hardware package, and the functional unit of the control unit 12 may be generated by executing a computer program in the CPU of the main body of the connection node apparatus 1. Instead of realizing the connection information generation units 38, 38a, 38aX, and 38aY as software as described above, a hardware package may be provided with an OTDR (Optical Time Domain Reflectometer) as the connection information generation unit 38, and transmission path information may be obtained by measurement using the OTDR.

[0262] The connection information generation units 38, 38a, 38aX, and 38aY may be provided outside the connection information processing units 13, 13a, 13b, 13aX, and 13aY. In this case, the connection information generation units 38, 38a, 38aX, and 38aY may be integrated with the control units 12, 12a, 12b, 12c, 12d, 12e, 12fX, and 12fY. Part of the processing of the connection information generation units 38, 38a, 38aX, and 38aY may be performed by either or both of the digital signal processing units 32, 32a, 32aX, and 32aY and the control units 12, 12a, 12b, 12c, 12d, 12e, 12fX, and 12fY. A configuration may be adopted in which some of the processing of the connection information generators 38, 38a, 38aX, 38aY is performed by the digital signal processors 32, 32a, 32aX, 32aY and the remaining processing is performed by the controllers 12, 12a, 12b, 12c, 12d, 12e, 12fX, 12fY, thereby eliminating the connection information generators 38, 38a, 38aX, 38aY. A configuration may be adopted in which the processing of the connection information generators 38, 38a, 38aX, 38aY is performed by the digital signal processors 32, 32a, 32aX, 32aY, thereby eliminating the connection information generators 38, 38a, 38aX, 38aY.

[0263] In the above first to fourth embodiments, for example, if a failure occurs in which the optical transmission path 51, 51-1 to 51-m is broken and the optical transceivers 21X, 21X-1 to 21X-m, 21aX-1 to 21aX-m, 21aX cannot generate a path for transmitting and receiving optical signals, the cause of the failure may be identified based on the results of transmission path loss measurements performed using test light transmitted from the connecting node devices 1, 1a, 1b, 1c, 1d, 1e, 1fX.

[0264] (Fifth embodiment) The fifth and subsequent embodiments are embodiments that solve the above-mentioned "problems related to monitoring and management." Fig. 21 is a block diagram showing the configuration of an optical transmission system 104 of the fifth embodiment. In the fifth embodiment, the same components as those shown in the above-mentioned embodiments are given the same reference numerals, and different components will be described below. In Fig. 21, the thick dotted lines indicate the paths of the optical wavelengths of the control signals, and the thick solid lines indicate the paths of the optical wavelengths of the main signals.

[0265] The optical transmission system 104 includes a connection node device 1g, optical communication devices 2gX and 2Y, an operation device 4g, optical transmission paths 51 and 52, and connection lines 3 and 3-1. The optical communication device 2gX is, for example, a transponder or other transceiver used by a user that transmits and receives optical signals, and the optical communication device 2Y is, for example, an optical transmission device owned by a telecommunications carrier, and is a node device in a carrier network, or a white-box transponder owned by a telecommunications carrier or a data center operator. The optical transceiver 21X included in the optical communication device 2gX and the optical transceiver 21Y included in the optical communication device 2Y are each a functional unit that transmits and receives a main signal, and each has the same configuration as that shown in the first and second embodiments.

[0266] The optical transmission path 51 is, for example, a dark fiber, and includes an optical fiber 51T and an optical fiber 51R, and connects the optical communication device 2gX and the connecting node device 1g. The optical transmission path 52 includes an optical fiber 52T and an optical fiber 52R, and connects the optical communication device 2Y and the connecting node device 1g. The connection line 3 connects the connecting node device 1g and the operation device 4g. The connection line 3-1 connects the optical communication device 2Y and the operation device 4g.

[0267] The connection node apparatus 1g, the optical transmission path 52, and the optical communication device 2Y are components of a communication network operated by an operator such as a telecommunications carrier, i.e., a so-called carrier network. However, as described above, the connection node apparatus 1g may be installed by a party other than the telecommunications carrier, such as a data center operator. As described above, the optical transmission path 51 may be, for example, a dark fiber, and may be provided by the telecommunications carrier that operates the carrier network, or may be installed and provided to users by a party other than the telecommunications carrier, such as a data center operator. Therefore, the dark fiber portion is not included in the so-called carrier network. Therefore, the optical communication device 2gX connected to the optical transmission path 51, which is a dark fiber, is not subject to monitoring or management by the telecommunications carrier. If a user of the optical communication device 2gX desires monitoring or management by the telecommunications carrier, the user must secure another communication path connected to the operation device 4g, connect the operation device 4g to the optical communication device 2gX, and request the telecommunications carrier to monitor and manage the optical communication device 2gX. This results in additional costs for the user to set up another communication path. The following describes a method for making the optical communication device 2gX a target for monitoring and management by a communication carrier without installing such a separate communication path.

[0268] The optical communication device 2gX includes an optical transceiver 21X, a control signal multiplexer / demultiplexer 6bX, a control signal transceiver 80tX, and a monitoring management processor 75X. The monitoring management processor 75X receives the electrical control signal output by the control signal transceiver 80tX and performs processing related to monitoring and management according to the type of the received control signal and the data included in the control signal. When transmitting a control signal to the operation device 4g in processing related to monitoring and management, the monitoring management processor 75X generates an electrical control signal and outputs it to the control signal transceiver 80tX.

[0269] The control signal transmitter / receiver 80tX converts the electrical control signal generated by the monitoring management processor 75X into an optical control signal and outputs it to the control signal multiplexer / demultiplexer 6bX. The control signal transmitter / receiver 80tX converts the optical control signal output by the control signal multiplexer / demultiplexer 6bX into an electrical control signal and outputs it to the monitoring management processor 75X. The control signal transmitter / receiver 80tX includes a control unit 81tX, an IF unit 82tX, a digital signal processor 83tX, an optical transmitter 84tX, and an optical receiver 87tX. The optical transmitter 84tX includes a wavelength-tunable light source 85tX and an optical modulator 86tX. The optical receiver 87tX includes an optical receiver 88tX. The control unit 81tX and the digital signal processor 83tX are connected to the monitoring management processor 75X via an electrical line. The IF unit 82tX is connected to the control signal multiplexer / demultiplexer 6bX via an optical fiber inside the optical communication device 2gX (not shown).

[0270] For the sake of convenience in the explanation of the fifth embodiment, the reference symbols are used differently, but the control unit 81tX, IF unit 82tX, digital signal processing unit 83tX, tunable wavelength light source 85tX, optical modulator 86tX, and optical receiver 88tX provided in the control signal transmission / reception unit 80tX each have the same configuration as the control unit 71aX-1, IF unit 22X-1, digital signal processing unit 23aX-1, tunable wavelength light source 25aX-1, optical modulator 26X-1, and optical receiver 28X-1, which are functional units provided in the optical transmission / reception unit 21aX-1 described in the third embodiment and have the same names except for the reference symbols.

[0271] The control signal multiplexing / demultiplexing unit 6bX is connected to the control signal transmitting / receiving unit 80tX and the optical transmitting / receiving unit 21X via an optical fiber inside the optical communication device 2gX (not shown), and is further connected to the optical transmission line 51. The control signal multiplexing / demultiplexing unit 6bX includes a wavelength multiplexing unit 8bX and a wavelength demultiplexing unit 7bX. The wavelength multiplexing unit 8bX wavelength-multiplexes the control signal optical signal output by the control signal transmitting / receiving unit 80tX and the main signal optical signal output by the optical transmitting / receiving unit 21X. The wavelength multiplexing unit 8bX transmits the wavelength-multiplexed optical signal to the optical fiber 51T of the optical transmission line 51. The wavelength demultiplexing unit 7bX wavelength-demultiplexes the wavelength-multiplexed optical signal transmitted by the optical fiber 51R of the optical transmission line 51 into the control signal optical signal and the main signal optical signal. The wavelength demultiplexing unit 7bX outputs the demultiplexed control signal optical signal to the control signal transmitting / receiving unit 80tX and outputs the demultiplexed main signal optical signal to the optical transmitting / receiving unit 21X.

[0272] The connection node device 1g includes a control unit 12g, a control signal multiplexing / demultiplexing unit 17, a control signal transmitting / receiving unit 80e, and an internal optical line 90 for control signals. The internal optical line 90 for control signals is an optical line consisting of an optical fiber 90T and an optical fiber 90R. The control unit 12g is connected to the connection line 3, and upon receiving data transmitted by the operation device 4g via the connection line 3, generates an electrical control signal according to the type of the received data and outputs the generated electrical control signal to the control signal transmitting / receiving unit 80e. Upon receiving the electrical control signal output by the control signal transmitting / receiving unit 80e, the control unit 12g transmits the data included in the received control signal to the operation device 4g via the connection line 3.

[0273] 22, the control signal transmitting / receiving unit 80e includes a control unit 81e, an IF unit 82e, a digital signal processing unit 83e, an optical transmitting unit 84e, and an optical receiving unit 87e. The optical transmitting unit 84e includes a tunable wavelength light source 85e and an optical modulator 86e. The optical receiving unit 87e includes an optical receiver 88e. The control signal transmitting / receiving unit 80e and the control signal transmitting / receiving unit 80tX included in the optical communication device 2gX have the same configuration. More specifically, the control unit 81e, the IF unit 82e, the digital signal processing unit 83e, the optical transmitting unit 84e, and the optical receiving unit 87e each have the same configuration as the functional units included in the control signal transmitting / receiving unit 80tX, which have the same names, excluding the reference numerals, i.e., the control unit 81tX, the IF unit 82tX, the digital signal processing unit 83tX, the optical transmitting unit 84tX, and the optical receiving unit 87tX. In the control signal transmitting / receiving unit 80e, the control unit 81e and the digital signal processing unit 83e are connected to the control unit 12g via electrical lines. The IF unit 82e is connected to an internal optical line 90 for control signals.

[0274] The control signal transmitting / receiving unit 80e converts the electrical control signal generated by the control unit 12g into an optical control signal, and outputs the converted optical control signal to the control signal multiplexing / demultiplexing unit 17 via the optical fiber 90R of the internal optical line 90 for control signals. The control signal transmitting / receiving unit 80e takes in the optical control signal output by the control signal multiplexing / demultiplexing unit 17 via the optical fiber 90T of the internal optical line 90 for control signals, converts the taken-in optical control signal into an electrical control signal, and outputs it to the control unit 12g.

[0275] The control signal multiplexing / demultiplexing unit 17 is connected to the optical transmission path 51, the optical transmission path 52, and the internal optical circuit for control signal 90. The control signal multiplexing / demultiplexing unit 17 includes a wavelength multiplexing unit 78 and a wavelength demultiplexing unit 77. The wavelength multiplexing unit 78 is connected at its input to the optical fiber 52R of the optical transmission path 52 and to the IF unit 82e of the control signal transmitting / receiving unit 80e via the optical fiber 90R, and is connected at its output to the optical fiber 51R of the optical transmission path 51. The wavelength demultiplexing unit 77 is connected at its input to the optical fiber 51T of the optical transmission path 51 and to the optical fiber 52T of the optical transmission path 52 and to the IF unit 82e of the control signal transmitting / receiving unit 80e via the optical fiber 90T.

[0276] The wavelength demultiplexer 77 wavelength-demultiplexes the wavelength-multiplexed optical signal transmitted through the optical fiber 51T of the optical transmission line 51 into an optical signal for a control signal and an optical signal for a main signal. As shown in FIG. 21 , a wavelength path 61T-C transmitting an optical signal for a control signal and a wavelength path 61T-1 transmitting an optical signal for a main signal are wavelength-multiplexed in the optical fiber 51T of the optical transmission line 51. In this case, the wavelength demultiplexer 77 wavelength-demultiplexes the wavelength path 61T-C from the wavelength path 61T-1, thereby demultiplexing the wavelength-multiplexed optical signal into an optical signal for a control signal and an optical signal for a main signal. The wavelength demultiplexer 77 outputs the demultiplexed optical signal for the control signal to the control signal transmitter / receiver 80e via the optical fiber 90T of the internal optical circuit 90 for control signals. The wavelength demultiplexer 7b transmits the demultiplexed optical signal for the main signal to the optical transmitter / receiver 21Y of the optical communication device 2Y via the optical fiber 52T of the optical transmission line 52.

[0277] The wavelength multiplexing unit 78 wavelength-multiplexes the optical signal of the control signal transmitted by the control signal transmitting / receiving unit 80e, which is received via the optical fiber 90R of the internal optical circuit 90 for control signals, with the optical signal of the main signal transmitted by the optical transmitting / receiving unit 21Y, which is received via the optical fiber 52R. The wavelength multiplexing unit 78 transmits the wavelength-multiplexed optical signal to the optical fiber 51R of the optical transmission line 51. As a result, as shown in FIG. 21 , the wavelength path 61R-C transmitting the optical signal of the control signal and the wavelength path 61R-1 transmitting the optical signal of the main signal are wavelength-multiplexed in the optical fiber 51R. Note that in FIG. 21 , the wavelength path 61T-1 of the optical transmission line 51 and the wavelength path 62T of the optical transmission line 52 are continuous wavelength paths that pass through the wavelength demultiplexing unit 77, and the wavelength path 62R of the optical transmission line 52 and the wavelength path 61R-1 of the optical transmission line 51 are continuous wavelength paths that pass through the wavelength multiplexing unit 78.

[0278] The wavelength separation unit 7bX and wavelength multiplexing unit 8bX of the control signal multiplexing / separation unit 6bX of the optical communication device 2gX, as well as the wavelength separation unit 77 and wavelength multiplexing unit 78 of the connection node device 1g, are composed of, for example, a 3dB coupler, a wavelength filter, an optical splitter, an AWG (Arrayed-Waveguide Grating), a C-band coupler, a C-band and O-band coupler, etc.

[0279] The operation device 4g includes a monitoring management control unit 44. In response to instructions from an operator who operates the operation device 4g, the monitoring management control unit 44 performs processing for monitoring and managing the optical communication device 2gX, the optical communication device 2Y, and the optical transmission paths 51 and 52. For example, the monitoring management control unit 44 performs processing for acquiring setting information including address information and configuration information of the optical transceiver 21 set in the optical transceiver 21X of the optical communication device 2gX.

[0280] (Assumed configuration for actual operation of the fifth embodiment) When the optical transmission system 104 of Fig. 21 is actually operated, the connecting node equipment 1g will accommodate a plurality of optical communication devices 2gX. Fig. 23 is a block diagram showing a configuration when the optical transmission system 104 is applied to such an actual operation scene, and this configuration will be referred to as the optical transmission system 104a hereinafter. The optical transmission system 104a includes a connecting node equipment 1g, a plurality of optical communication devices 2gX-1 to 2gX-m, a plurality of optical communication devices 2Y-1 to 2Y-m, an operation equipment 4g, a plurality of optical transmission paths 51-1 to 51-m, a plurality of optical transmission paths 52 to 52-m, a connecting line 3, and a plurality of connecting lines 3-1 to 3-m.

[0281] Each of the optical communication devices 2gX-1 to 2gX-m has the same configuration as the optical communication device 2gX. Each of the optical communication devices 2Y-1 to 2Y-m has the same configuration as the optical communication device 2Y. Each of the optical communication devices 2Y-1 to 2Y-m is connected to the operation device 4g via connection lines 3-1 to 3-m connecting to each of them. The connection node device 1g included in the optical transmission system 104a is connected to each of the optical communication devices 2gX-1 to 2gX-m and each of the optical communication devices 2Y-1 to 2Y-m. Therefore, the connection node device 1g includes m control signal transmitting / receiving units 80e-1 to 80e-m, the number of which corresponds to the number of the optical communication devices 2gX-1 to 2gX-m, and m control signal multiplexing / demultiplexing units 17-1 to 17-m. Each of the control signal transmitting / receiving units 80e-1 to 80e-m has the same configuration as the control signal transmitting / receiving unit 80e. Each of the control signal multiplexing / demultiplexing units 17-1 to 17-m has the same configuration as the control signal multiplexing / demultiplexing unit 17.

[0282] The optical communication devices 2gX-1 to 2gX-m are connected to the control signal multiplexing / demultiplexing units 17-1 to 17-m, respectively, by optical transmission paths 51-1 to 51-m. The control signal multiplexing / demultiplexing units 17-1 to 17-m are connected to the optical communication devices 2Y-1 to 2Y-m, respectively, by optical transmission paths 52 to 52-m. Like the optical transmission path 51, each of the optical transmission paths 51-1 to 51-m includes two optical fibers, and like the optical transmission path 52, each of the optical transmission paths 52 to 52-m includes two optical fibers.

[0283] The control signal transmitting / receiving units 80e-1 to 80e-m are connected to the control signal multiplexing / demultiplexing units 17-1 to 17-m, respectively, by internal optical circuits 90-1 to 90-m for control signals. Each of the internal optical circuits 90-1 to 90-m for control signals includes two optical fibers, similar to the internal optical circuit 90 for control signals. A control unit 12g included in the connection node device 1g is connected to each of the control signal transmitting / receiving units 80e-1 to 80e-m via an electrical circuit.

[0284] Hereinafter, when referring to functional units of optical communication devices 2gX-1 to 2gX-m corresponding to functional units included in the optical communication device 2gX, when referring to functional units of optical communication devices 2Y-1 to 2Y-m corresponding to functional units included in the optical communication device 2Y, when referring to functional units of control signal transmitters and receivers 80e-1 to 80e-m corresponding to functional units included in the control signal transmitter and receiver 80e, when referring to functional units of control signal multiplexing / demultiplexing units 17-1 to 17-m corresponding to functional units included in the control signal multiplexing / demultiplexing unit 17, and when referring to optical fibers of internal optical circuits for control signal 90-1 to 90-m corresponding to optical fibers 90T, 90R of the internal optical circuit for control signal 90, a branch number of the reference number of the target will be added to the original reference number. For example, the functional unit of optical communication device 2gX-1 corresponding to the monitoring management processing unit 75X included in the optical communication device 2gX will be referred to as a monitoring management processing unit 75X-1.

[0285] In the fifth embodiment, unlike the first to fourth embodiments described above, optical wavelength paths used for transmitting and receiving main signals between each of the optical communication devices 2gX-1 to 2gX-m and each of the optical communication devices 2Y-1 to 2Y-m are manually generated. For example, an operator of a telecommunications carrier manually performs the processing performed by the control unit 12 of the connection node device 1 in the first embodiment and the path detection unit 41 and transmission path design unit 42 of the operation device 4 in the second embodiment, to generate configuration information indicating the optimal transmission mode for each of m combinations, namely, the combination of optical transmission paths 51-1 and 52-1, the combination of optical transmission paths 51-2 and 52-2, ..., the combination of optical transmission paths 51-m and 52-m. Based on the generated configuration information, the operator generates setting information for setting wavelength paths of main signals between each of the optical communication devices 2gX-1 to 2gX-m and each of the optical communication devices 2Y-1 to 2Y-m.

[0286] For example, the operator connects a management terminal device to each of the control units 71X-1 to 71X-m provided in the optical transceivers 21X-1 to 21X-m of the optical communication devices 2gX-1 to 2gX-m. The operator operates the management terminal device to write corresponding setting information to each of the internal storage areas of the control units 71X-1 to 71X-m and operate the optical transceivers 21X-1 to 21X-m in accordance with the written setting information. For example, the operator operates the monitoring management control unit 44 of the operation device 4g to write corresponding setting information to each of the internal storage areas of the control units 71Y-1 to 71Y-m provided in the optical transceivers 21Y-1 to 21Y-m of the optical communication devices 2Y-1 to 2Y-m and operate the optical transceivers 21Y-1 to 21Y-m in accordance with the written setting information. As a result, an optical wavelength path is created between each of the optical transceivers 21X-1 to 21X-m and each of the optical transceivers 21Y-1 to 21Y-m, and a main signal wavelength path is opened between each of the optical transceivers 21X-1 to 21X-m and each of the optical transceivers 21Y-1 to 21Y-m.

[0287] The operator generates a route management table 45 indicating the generated wavelength routes in a storage area of ​​the monitoring management control unit 44 of the operation device 4g based on the setting information used to generate the wavelength routes of the main signals. The route management table 45 is a data-format table having the following fields: "route identification number," "first route end information," "second route end information," and "main signal wavelength," as shown in FIG. 24 . The "route identification number" field contains a route identification number assigned to uniquely identify the wavelength route of the generated main signal. Here, an example is shown in which route identification numbers of "1," "2," ..., "m" are assigned to the wavelength routes of the main signals generated on the optical transmission lines 51-1 and 52-1, the wavelength routes of the main signals generated on the optical transmission lines 51-2 and 52-2, ..., the wavelength routes of the main signals generated on the optical transmission lines 51-m and 52-m. The final field, "main signal wavelength," contains the wavelength value of the wavelength route of the main signal corresponding to the route identification number in the corresponding "route identification number" field.

[0288] Each of the items "First route end information" and "Second route end information" has the same sub-items, namely, "Monitoring object identification information," "Connection path," "Control signal line," and "Whether via connection node." Address information identifying the optical transceivers 21X-1 to 21X-m and 21Y-1 to 21Y-m connected to one end of the wavelength path is written in the "Monitoring object identification information." Identification information identifying the optical transmission paths 51-1 to 51-m and 52-1 to 52-m to which the optical transceivers 21X-1 to 21X-m and 21Y-1 to 21Y-m indicated by the address information in the corresponding "Monitoring object identification information" item is written in the "Connection path."

[0289] In the "control signal line" field, identification information is written that identifies the connection line 3, 3-1 to 3-m for accessing the optical transceivers 21X-1 to 21X-m, 21Y-1 to 21Y-m that corresponds to the address information written in the corresponding "monitoring target identification information" field. In the case of the optical transceivers 21X-1 to 21X-m, the operation device 4g accesses them via the connection node device 1g, so identification information is written that identifies the connection line 3 that connects the operation device 4g and the connection node device 1g.

[0290] On the other hand, in the case of the optical transceivers 21Y-1 to 21Y-m, the operation device 4g can directly access them via the connection lines 3-1 to 3-m, and therefore, identification information for identifying each of the connection lines 3-1 to 3-m is written. Note that identification information for uniquely identifying each of the connection lines 3, 3-1, 3-2, ... is previously assigned to each of all the connection lines 3, 3-1, 3-2, .... In the "via connection node" field, "yes" is written if access is possible via the connection node apparatus 1g, and "no" is written if access is possible without via the connection node apparatus 1g.

[0291] Note that Figure 24 shows an example in which data regarding the user's optical communication devices 2gX-1 to 2gX-m is written in the "first route end information" field and data regarding the carrier's optical communication devices 2Y-1 to 2Y-m is written in the "second route end information" field, but the opposite pattern may also be used, i.e., data regarding the carrier's optical communication devices 2Y-1 to 2Y-m is written in the "first route end information" field and information regarding the user's optical communication devices 2gX-1 to 2gX-m is written in the "second route end information" field.

[0292] Based on the configuration of the connection node apparatus 1g, the operator performs an operation to generate, in an internal storage area of ​​the control unit 12g of the connection node apparatus 1g, a control signal transmitter / receiver correspondence table 18 indicating which optical transmission paths 51-1 to 51-m each of the control signal transmitter / receivers 80e-1 to 80e-m corresponds to. As shown in FIG. 25, the control signal transmitter / receiver correspondence table 18 is a table in a data format having items of "connection path" and "control signal transmitter / receiver identification information." Identification information identifying the control signal transmitter / receiver 80e-1 to 80e-m is written in the item of "control signal transmitter / receiver identification information." Note that identification information uniquely identifying each of the control signal transmitter / receivers 80e-1 to 80e-m is assigned in advance to each of the control signal transmitter / receivers 80e-1 to 80e-m. In the "Connection Path" field, identification information is written that specifies the optical transmission paths 51-1 to 51-m, 52-1 to 52-m corresponding to the control signal transmitter / receiver 80e-1 to 80e-m indicated by the identification information in the corresponding "Control Signal Transceiver Identification Information" field.

[0293] (Processing by the optical transmission system of the fifth embodiment) An example of processing performed by the optical transmission system 104a will be described with reference to the sequence diagram shown in Fig. 26. Before the processing shown in the sequence diagram of Fig. 26 is started, the optical transmission system 104a is assumed to be in the following state. A wavelength route of a main signal is generated between each of the optical transceivers 21X-1 to 21X-m of the optical communication devices 2gX-1 to 2gX-m and the optical transceivers 21Y-1 to 21Y-m of the optical communication devices 2Y-1 to 2Y-m. An operational state is established in which a main signal optical signal is transmitted and received via the wavelength route generated for each combination of the optical transceivers 21X-1 and 21Y-1, the optical transceivers 21X-2 and 21Y-2, ..., and the optical transceivers 21X-m and 21Y-m. A route management table 45 shown in Fig. 24 has been generated in a storage area within the monitoring management control unit 44 by an operator. In the internal storage area of ​​the control unit 12g of the connection node device 1g, a control signal transmitting / receiving unit correspondence table 18 shown in FIG. 25 is generated by an operator's operation.

[0294] For example, the process will be described with reference to the sequence diagram of Figure 26, assuming that an operator acquires the setting information set in the optical transceiver unit 21X-1 in order to check the transmission mode of the digital signal processing unit 23X-1 of the optical transceiver unit 21X-1 of the optical communication device 2gX-1 connected to the connection node device 1g.

[0295] The operator instructs the monitoring management control unit 44 of the operation device 4g to generate and transmit a setting information acquisition request signal specifying the address information of the optical transceiver 21X-1. Upon receiving this instruction, the monitoring management control unit 44 refers to the route management table 45 stored in an internal storage area and detects a record with a route identification number in which the address information in the "monitoring target identification information" field matches the address information of the specified optical transceiver 21X-1. As shown in FIG. 24, the address information of the optical transceiver 21X-1 exists in the "monitoring target identification information" field of the sub-field "first route end information" of the record with the route identification number "1", so the monitoring management control unit 44 detects the record with the route identification number "1".

[0296] In the record with the detected route identification number "1", the monitoring management control unit 44 refers to the "whether via connection node" item in the sub-item of "first route end information" for the side where the address information of the optical transceiver 21X-1 is included in the "monitoring target identification information" item. If the "whether via connection node" item is "yes", the monitoring management control unit 44 performs a process of selecting a wavelength value for transmitting and receiving a control signal, since the connecting node device 1g is present as the destination of the setting information acquisition request signal. The monitoring management control unit 44 refers to the wavelength value of the wavelength route of the main signal in the "main signal wavelength" item in the record with the detected route identification number "1", and selects a wavelength value different from the referenced value as the wavelength value of the control signal.

[0297] The monitoring management control unit 44 reads out identification information for identifying the optical transmission path 51-1 written in the "Connection Path" item of the sub-item "First Route End Information" of the record with the detected route identification number "1", and generates a setting information acquisition request signal including the read out identification information for identifying the optical transmission path 51-1 and the wavelength value of the selected control signal (step Se1). The monitoring management control unit 44 transmits the generated setting information acquisition request signal to the connecting node device 1g via the connection line 3 indicated in the "Control Signal Line" item of the sub-item "First Route End Information" of the record with the detected route identification number "1" (step Se2).

[0298] The control unit 12g of the connection node device 1g receives the setting information acquisition request signal transmitted by the monitoring management control unit 44 via the connection line 3. The control unit 12g reads out identification information for identifying the optical transmission path 51-1, which is included in the received setting information acquisition request signal. The control unit 12g refers to the control signal transmitting / receiving unit correspondence table 18 stored in an internal storage area, and detects a record in which the identification information in the "Connection Path" field matches the identification information for identifying the read optical transmission path 51-1. The control unit 12g selects the control signal transmitting / receiving units 80e-1 to 80e-m corresponding to the identification information written in the "Control Signal Transceiver Identification Information" field of the detected record as the control signal transmitting / receiving units 80e-1 to 80e-m that will transmit the control signal. As shown in FIG. 25, the identification information for identifying the optical transmission path 51-1 is associated with the identification information for the control signal transmitting / receiving unit 80e-1. Therefore, in this case, the control unit 12g selects the control signal transmitting / receiving unit 80e-1 (step Se3).

[0299] The control unit 12g reads the wavelength value of the control signal included in the received setting information acquisition request signal and outputs the read wavelength value of the control signal to the control unit 81e-1 of the selected control signal transmitting / receiving unit 80e-1. Upon receiving the wavelength value of the control signal from the control unit 12g, the control unit 81e-1 outputs a wavelength designation signal that designates the received wavelength value to the wavelength-tunable light source 85e-1. As a result, the wavelength-tunable light source 85e-1 generates and outputs continuous light having a wavelength value that is the wavelength value of the control signal selected by the monitoring management control unit 44 and that is different from the wavelength value of the optical signal of the main signal transmitted by the optical fiber 51T of the optical transmission path 51.

[0300] The control unit 12g generates an electrical control signal of the type corresponding to the setting information acquisition request, including the information contained in the received setting information acquisition request signal, and outputs the generated electrical control signal to the digital signal processing unit 83e-1 of the selected control signal transmitting / receiving unit 80e-1 (step Se4).

[0301] The digital signal processing unit 83e-1 of the control signal transmitting / receiving unit 80e-1 receives the electrical control signal output by the control unit 12g and outputs the received electrical control signal to the optical modulator 86e-1. The optical modulator 86e-1 optically modulates the continuous light having the wavelength of the control signal output by the tunable light source 85e-1 with the received electrical control signal. The optical modulator 86e-1 outputs the optical signal of the control signal generated by the optical modulation to the IF unit 82e-1. The IF unit 82e-1 receives the optical signal of the control signal output by the optical modulator 86e-1. The IF unit 82e-1 outputs the received optical signal of the control signal to the wavelength multiplexing unit 78-1 of the control signal multiplexing / demultiplexing unit 17-1 via the optical fiber 90R-1 of the internal optical line 90-1 for control signals.

[0302] The wavelength multiplexing unit 78-1 wavelength-multiplexes the optical signal of the control signal output by the IF unit 82e-1 received via the optical fiber 90R-1 and the optical signal of the main signal transmitted by the optical transceiver 21Y-1 of the optical communication device 2Y-1 received via the wavelength path 62R-1 of the optical fiber 52R included in the optical transmission line 52. The wavelength multiplexing unit 78-1 transmits the wavelength-multiplexed optical signal to the optical fiber 51R-1 of the optical transmission line 51-1.

[0303] The optical fiber 51R-1 transmits the wavelength-multiplexed optical signal sent by the wavelength multiplexing unit 78-1 to the wavelength demultiplexing unit 7bX-1 of the control signal multiplexing / demultiplexing unit 6bX-1 included in the optical communication device 2gX-1. The wavelength demultiplexing unit 7bX-1 wavelength-demultiplexes the wavelength-multiplexed optical signal transmitted by the optical fiber 51R-1 into an optical control signal signal and an optical main signal. The wavelength demultiplexing unit 7bX-1 outputs the demultiplexed optical control signal signal to the IF unit 82tX-1 of the control signal transmitting / receiving unit 80tX-1, and outputs the demultiplexed optical main signal signal to the optical transmitting / receiving unit 21X-1 (step Se5).

[0304] The IF unit 82tX-1 of the control signal transmitter / receiver 80tX-1 receives the optical signal of the control signal output by the wavelength demultiplexer 7bX-1 and outputs the received optical signal of the control signal to the optical receiver 88tX-1. The optical receiver 88tX-1 receives the optical signal of the control signal output by the IF unit 82tX-1 and converts the received optical signal into an electrical control signal. The optical receiver 88tX-1 outputs the control signal to the digital signal processor 83tX-1. The digital signal processor 83tX-1 receives the control signal output by the optical receiver 88tX-1. The digital signal processor 83tX-1 outputs the received control signal to the monitoring management processor 75X-1 (step Se6).

[0305] The monitoring management processing unit 75X-1 receives the control signal output by the digital signal processing unit 83tX-1. Since the type of the received control signal is a setting information acquisition request type, the monitoring management processing unit 75X-1 outputs a setting information acquisition request signal to the control unit 71X-1 of the optical transceiver 21X-1 (step Se7). Upon receiving the setting information acquisition request signal from the monitoring management processing unit 75X-1, the control unit 71X-1 of the optical transceiver 21X-1 performs processing to acquire setting information as follows. Specifically, the control unit 71X-1 collects information set in the optical transmitter 24X-1 from the digital signal processing unit 23X-1 and the optical transmitter 24X-1. The control unit 71X-1 generates setting information by adding information such as the address information of the optical transmitter 21X-1 stored in its own internal storage area to the information collected from the digital signal processing unit 23X-1 and the optical transmitter 24X-1 (step Se8).

[0306] The control unit 71X-1 of the optical transceiver 21X-1 outputs the acquired setting information to the monitoring management processing unit 75X-1 (step Se9). The monitoring management processing unit 75X-1 receives the setting information output by the control unit 71X-1 and generates an electrical control signal including the received setting information. The monitoring management processing unit 75X-1 reads the wavelength value of the control signal from the control signal received in the processing of step Se7 and outputs the read wavelength value of the control signal to the control unit 81tX-1 of the control signal transceiver 80tX-1. Note that the processing by the monitoring management processing unit 75X-1 to output the wavelength value of the control signal to the control unit 81tX-1 of the control signal transceiver 80tX-1 may be performed in advance at the timing of step Se7. Upon receiving the wavelength value of the control signal from the monitoring management processing unit 75X-1, the control unit 81tX-1 outputs a wavelength designation signal that designates the received wavelength value to the wavelength-tunable light source 85tX-1. As a result, the tunable light source 85tX-1 generates and outputs continuous light having a wavelength value that is the wavelength value of the control signal selected by the monitoring management control unit 44 and that is different from the wavelength value of the main optical signal transmitted by the optical fiber 51R of the optical transmission path 51. The monitoring management processing unit 75X-1 outputs the generated electrical control signal including the setting information to the digital signal processing unit 83tX-1 of the control signal transmitting / receiving unit 80tX-1 (step Se10).

[0307] The digital signal processing unit 83tX-1 of the control signal transmitting / receiving unit 80tX-1 receives the electrical control signal output by the monitoring management processing unit 75X-1 and outputs the received electrical control signal to the optical modulator 86tX-1. The optical modulator 86tX-1 optically modulates the continuous light having the wavelength of the control signal output by the tunable wavelength light source 85tX-1 with the received electrical control signal. The optical modulator 86tX-1 outputs the optical signal of the control signal generated by the optical modulation to the IF unit 82tX-1. The IF unit 82tX-1 receives the optical signal of the control signal output by the optical modulator 86tX-1. The IF unit 82tX-1 outputs the received optical signal of the control signal to the wavelength multiplexing unit 8bX-1 of the control signal multiplexing / demultiplexing unit 6bX-1. The wavelength multiplexing unit 8bX-1 wavelength-multiplexes the optical signal of the control signal output by the IF unit 82tX-1 and the optical signal of the main signal transmitted by the optical transceiver 21X-1, and transmits the wavelength-multiplexed optical signal to the optical fiber 51T-1 of the optical transmission line 51-1.

[0308] The optical fiber 51...

Claims

1. a transmission path design unit that performs a transmission mode specification process for specifying a transmission mode to be used in communication between the first optical communication device and the second optical communication device, based on transmission path information of a first optical transmission path connecting a first node device to which a first optical communication device is connected and a second node device to which a second optical communication device is connected, and on available resource information of the first optical transmission path; An operation device comprising:

2. The transmission path design unit performing the transmission mode specifying process by further using transmission path information of a second optical transmission path connecting the first optical communication device and the first node device and transmission path information of a third optical transmission path connecting the second optical communication device and the second node device; The operation device according to claim 1 .

3. The transmission path design unit calculating transmission path characteristics of an optical transmission path from the second optical transmission path to the third optical transmission path via the first optical transmission path based on connection information of the second optical transmission path obtained from the first node device, connection information of the third optical transmission path obtained from the second node device, and transmission path information of the first optical transmission path, and specifying the transmission mode based on the calculated transmission path characteristics and available resource information of the first optical transmission path; The operation device according to claim 2 .

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