Optical transmission system

Abstract

In optical transmission systems, control becomes complex when extending a termination point of an optical signal propagating through a submarine cable. Therefore, this optical transmission system includes: a first optical device comprising a first optical signal adjustment means configured to adjust the light intensity of an input optical signal for each wavelength, and a first control means for controlling the first optical signal adjustment means; and a second optical device comprising a second control means. The second control means transmits, to the first control means, transmitted light information that is information relating to a transmitted optical signal, and the first control means uses the transmitted light information to control the first optical signal adjustment means such that the transmitted light signal is allowed to pass.

Description

Technical Field

[0001] The present invention relates to an optical transmission system and an optical transmission method, and particularly to an optical transmission system and an optical transmission method used together with an optical submarine cable system.

Background Art

[0002] An optical submarine cable system that connects between continents with optical fibers plays an important role as infrastructure that supports international communication networks. The optical submarine cable system is composed of a submarine cable that houses optical fibers, a submarine repeater equipped with an optical amplifier, a submarine branching device that branches optical signals, and a terminal device installed at a landing station. An example of such an optical submarine cable system is described in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an optical submarine cable system, in recent years, an optical transmission system that divides the operating wavelength band of a single optical fiber into a plurality of sub-bands and assigns different customers (users) to each sub-band has attracted attention.

[0005] On the one hand, the volume of communication traffic between large-scale data centers deployed worldwide tends to increase. Along with the increase in the volume of communication traffic between data centers, an increase in delay and power consumption due to terminating optical signals (optical paths) at a cable landing station (CLS) have become problems. To avoid such problems, there is a desire to extend the termination point of the optical signal propagating through the undersea cable to a customer's data center installed inland from the cable landing station (CLS) or a point of presence (POP) that is a connection point to a backbone network.

[0006] However, in this case, since the optical device installed at the cable landing station (CLS) and the optical device owned by the customer at the data center or POP are separate devices, it is necessary to control each optical device individually. Therefore, in order to realize one function by interlocking the optical device installed at the cable landing station (CLS) and the optical device installed at the POP or the like, complicated control is required.

[0007] Thus, in the optical transmission system, there has been a problem that when the termination point of the optical signal propagating through the undersea cable is extended, the control becomes complicated.

[0008] An object of the present invention is to provide an optical transmission system and an optical transmission method that solve the problem that when the termination point of the optical signal propagating through the undersea cable is extended in the optical transmission system, which is the above-described problem, the control becomes complicated.

Means for Solving the Problem

[0009] The optical transmission system of the present invention includes a first optical device including a first optical signal adjustment means configured to adjust the optical intensity of an input optical signal for each wavelength, and a first control means for controlling the first optical signal adjustment means, and a second optical device including a second control means. The second control means sends transmission optical information, which is information regarding the transmission optical signal, to the first control means, and the first control means controls the first optical signal adjustment means to pass the transmission optical signal using the transmission optical information.

[0010] The optical transmission method of the present invention acquires transmission optical information which is information regarding a transmission optical signal, and uses the transmission optical information to pass the transmission optical signal by adjusting the optical intensity for each wavelength.

Advantages of the Invention

[0011] According to the optical transmission system and the optical transmission method of the present invention, in the optical transmission system, even when the end point of the optical signal propagating through the submarine cable is extended, the control can be simplified.

Brief Description of the Drawings

[0012]

Figure 1

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Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] 〔First Embodiment〕 FIG. 1 is a block diagram showing the configuration of an optical transmission system 1000 according to the first embodiment of the present invention. The optical transmission system 1000 includes a first optical device 1100 and a second optical device 1200. The optical transmission system 1000 is preferably used together with an optical submarine cable system.

[0015] The first optical device 1100 includes a first optical signal adjustment unit (first optical signal adjustment means) 1110 and a first control unit (first control means) 1120. The first optical signal adjustment unit 1110 is configured to adjust the optical intensity of the input optical signal for each wavelength. The first control unit 1120 controls the first optical signal adjustment unit 1110.

[0016] The second optical device 1200 includes a second control unit (second control means) 1210.

[0017] Here, the second control unit 1210 sends transmission optical information, which is information regarding the transmission optical signal, to the first control unit 1120. Then, the first control unit 1120 uses this transmission optical information to control the first optical signal adjustment unit 1110 so as to pass the transmission optical signal.

[0018] The first optical device 1100 is typically installed at a connection point (Point of Presence: POP) to a data center or a backbone network. Also, the second optical device 1200 is typically installed at a Cable Landing Station (CLS) of an optical submarine cable system. In this case, the end point of the optical signal propagating through the submarine cable can be extended to a data center or a POP.

[0019] When the first optical device 1100 and the second optical device 1200 are located separately, such as at a point of presence (POP) and a cable landing station (CLS), it is necessary to control each of the first optical device 1100 and the second optical device 1200. Therefore, in order to realize a single function by interlocking the first optical device 1100 and the second optical device 1200, complex control is required.

[0020] On the other hand, in the optical transmission system 1000 according to the present embodiment, the second control unit 1210 sends transmission optical information to the first control unit 1120, and the first control unit 1120 uses the transmission optical information to pass a transmission optical signal. The first optical signal adjustment unit 1110 is controlled. Therefore, by simply performing an operation for instructing the start of operation on the second optical device 1200, it is possible to control the transmission optical signal to pass through the first optical device 1100 and be introduced into the second optical device 1200. That is, according to the optical transmission system 1000 of the present embodiment, in the optical transmission system, even when the end point of the optical signal propagating through the submarine cable is extended, the control can be simplified.

[0021] Here, the second control unit 1210 may be configured to send the transmission optical information to the first control unit 1120 via the optical transmission path 10 through which the transmission optical signal propagates from the first optical device 1100 to the second optical device 1200. That is, the second control unit 1210 may be configured to send the transmission optical information to the first control unit 1120 by an in-band method via the optical transmission path 10 that transmits the main optical signal. Specifically, for example, an optical transceiver is attached to the ports of the switching hubs (layer 2 switches) connected to the first optical device 1100 and the second optical device 1200, respectively, and the transmission optical information can be sent through the optical transmission path 10 by these optical transceivers. As the optical transceiver in this case, typically an SFP (Small Form-factor Pluggable) module can be used.

[0022] The first optical signal adjustment unit 1110 can be configured to include a first connection port configured to connect to an optical transponder that generates a transmission optical signal, and a second connection port configured to connect to an optical transmission line 10 laid on land. As the first optical signal adjustment unit 1110, typically, a wavelength selectable switch (WSS) can be used. The wavelength selectable switch (WSS) can select the path of the signal light for each wavelength and has a bandwidth variable function and an attenuation amount adjustment function. In this case, the first optical signal adjustment unit 1110 can pass the transmission optical signal by the bandwidth variable function and the attenuation amount adjustment function provided by the wavelength selectable switch (WSS).

[0023] The transmission optical information can include at least the central wavelength, the bandwidth of the transmission optical signal, and the connection port number of the first optical signal adjustment unit 1110 into which the transmission optical signal is introduced. Here, the second optical device 1200 acquires the transmission optical information from, for example, an element management system (EMS) of a station device in an optical submarine cable system.

[0024] Next, the optical transmission method according to the present embodiment will be described using the flowchart shown in FIG. 2.

[0025] In the optical transmission method according to the present embodiment, first, transmission optical information, which is information regarding the transmission optical signal, is acquired (step S110). Then, using this transmission optical information, the transmission optical signal is passed by adjusting the optical intensity for each wavelength (step S120).

[0026] Thus, the optical transmission method of the present embodiment is configured to acquire transmission optical information, which is information regarding the transmission optical signal, and use this transmission optical information to adjust the optical intensity for each wavelength to pass the transmission optical signal. Therefore, it is possible to conduct the transmission optical signal with a simple operation.

[0027] The acquisition of the above-described transmitted optical information can include acquiring the transmitted optical information via the optical transmission path through which the transmitted optical signal propagates. Further, passing the above-described transmitted optical signal can include receiving the transmitted optical signal from an optical transponder and sending the transmitted optical signal to an optical transmission path laid on land. Here, the transmitted optical information can include at least the central wavelength and bandwidth of the transmitted optical signal.

[0028] As described above, according to the optical transmission system 1000 and the optical transmission method of the present embodiment, in the optical transmission system, even when the end point of the optical signal propagating through the undersea cable is extended, the control can be simplified.

[0029] 〔Second Embodiment〕 Next, a second embodiment of the present invention will be described. FIG. 3 shows the configuration of an optical transmission system 2000 according to the present embodiment. The optical transmission system 2000 includes a first optical device 2100 and a second optical device 2200. The optical transmission system 2000 is preferably used together with an optical undersea cable system.

[0030] The first optical device 2100 includes a first optical signal adjustment unit (first optical signal adjustment means) 2110 and a first control unit (first control means) 2120. The first optical signal adjustment unit 2110 is configured to adjust the optical intensity of the input optical signal for each wavelength. The first control unit 2120 controls the first optical signal adjustment unit 2110.

[0031] The second optical device 2200 includes a second control unit (second control means) 2210. The second control unit 2210 sends transmitted optical information, which is information about the transmitted optical signal, to the first control unit 2120. Then, the first control unit 2120 controls the first optical signal adjustment unit 2110 to pass the transmitted optical signal using this transmitted optical information.

[0032] Here, the second optical device 2200 acquires transmitted optical information from, for example, a monitoring device (EMS) of station equipment in an optical undersea cable system.

[0033] The first optical device 2100 is typically installed at a point of presence (POP) for connection to a data center or a backbone network. Also, the second optical device 2200 is typically installed at a cable landing station (CLS) of an optical submarine cable system. In this case, the termination point of the optical signal propagating through the submarine cable can be extended to the data center or the POP.

[0034] The configuration up to this point is the same as that of the optical transmission system 1000 according to the first embodiment. In the optical transmission system 2000 according to the present embodiment, the second optical device 2200 is configured to further include a dummy light generation unit (dummy light generation means) 2220 and an optical monitor unit (optical monitor means) 2230. Also, the second control unit 2210 is configured to include a storage unit (storage means) 2211.

[0035] The dummy light generation unit 2220 generates dummy light. As the dummy light generation unit 2220, for example, an ASE (Amplified Spontaneous Emission) light source in a state where an amplifier using an erbium-doped fiber (Erbium Doped Fiber Amplifier: EDFA) has no input signal can be used.

[0036] The optical monitor unit 2230 monitors the optical intensity of the received input light for each wavelength and generates optical monitor information. As the optical monitor unit 2230, typically an optical channel monitor (OCM) can be used.

[0037] The memory unit 2211 is configured to store optical intensity setting information for compensating the optical transmission characteristics of the undersea optical transmission line 20 to which the second optical device 2200 is connected. The optical intensity setting information is information regarding the optical intensity (pre-emphasis) preset for each wavelength in accordance with this wavelength dependency so as to compensate for the wavelength dependency of the optical intensity in the undersea optical transmission line 20. An example of the optical intensity setting information is schematically shown in FIG. 4. The memory unit 2211 can hold the values of the optical intensity for such respective wavelengths, for example, in a table format. The second optical device 2200 can acquire the optical intensity setting information by introducing the dummy light generated by the dummy light generation unit 2220 into the undersea optical transmission line 20 and measuring in advance the wavelength dependency of the optical intensity in the undersea optical transmission line 20.

[0038] Next, the operation of the optical transmission system 2000 according to the present embodiment will be described.

[0039] The optical monitor unit 2230 receives the transmitted optical signal and the dummy light, and generates first optical monitor information which is optical monitor information. The second control unit 2210 sends the first optical monitor information and the optical intensity setting information to the first control unit 2120 via the optical transmission line 10. Then, the first control unit 2120 controls the first optical signal adjuster 2110 so that the optical intensity of the transmitted optical signal conforms to the optical intensity setting information by using the first optical monitor information.

[0040] Typically, a wavelength selective switch (WSS) can be used as the first optical signal adjuster 2110. In this case, the first optical signal adjuster 2110 can make the optical intensity of the transmitted optical signal conform to the optical intensity setting information by means of the attenuation amount adjustment function provided in the wavelength selective switch (WSS).

[0041] Also, the second control unit 2210 can be configured to control the dummy light generation unit 2220 so that the optical intensity of the dummy light conforms to the optical intensity setting information by using the first optical monitor information.

[0042] With the above-described configuration, the first optical device 2100 can acquire the optical intensity setting information from the second optical device 2200. Therefore, the first optical device 2100 can adapt the optical intensity of the transmitted optical signal to the optical intensity setting information. As a result, by simply performing an operation of instructing the second optical device 2200 to start operation by an external device such as a monitoring device (EMS), a function of automatically inserting a transmitted optical signal that conforms to the optical intensity setting information can be realized. That is, according to the optical transmission system 2000 of the present embodiment, even when the end point of the optical signal propagating through the submarine cable is extended in the optical transmission system, the control can be simplified.

[0043] FIG. 5 shows another configuration of the optical transmission system according to the present embodiment. In the optical transmission system 2001, the second optical device 2201 further includes a second optical signal adjustment unit (second optical signal adjustment means) 2240.

[0044] The second optical signal adjustment unit 2240 receives the first transmitted optical signal, which is the above-described transmitted optical signal, from the first optical device 2100, and receives the second transmitted optical signal from the third optical device 3000. Then, the second optical signal adjustment unit 2240 is configured to adjust the optical intensities of the first transmitted optical signal and the second transmitted optical signal for each wavelength and multiplex them.

[0045] In this case, the optical monitor unit 2230 receives the first transmitted optical signal, the second transmitted optical signal, and the dummy optical signal, and generates the second optical monitor information, which is the above-described optical monitor information. Then, the second control unit 2210 controls the second optical signal adjustment unit 2240 so that the optical intensities of the first transmitted optical signal and the second transmitted optical signal conform to the optical intensity setting information using the second optical monitor information. Further, the second control unit 2210 can be configured to control the dummy optical signal generation unit 2220 so that the optical intensity of the dummy optical signal conforms to the optical intensity setting information using the second optical monitor information.

[0046] FIG. 6 shows an example of the spectrum of the wavelength-division multiplexed optical signal output from the second optical device 2201. In this figure, the case where the wavelength-division multiplexed optical signal includes four transmission optical signals S1, S2, S3, S4, and dummy light D0 is shown as an example. The curve indicated by the broken line in the figure shows the optical intensity setting information shown in FIG. 4. By using such a wavelength-division multiplexed optical signal, it is possible to compensate for the wavelength dependence of the optical intensity in the undersea optical transmission line 20.

[0047] The second optical signal adjuster 2240 can be configured to include a third connection port configured to connect to the optical transmission line 10 laid on land and a fourth connection port configured to connect to the undersea optical transmission line 20. As the second optical signal adjuster 2240, typically, a wavelength selective switch (WSS) can be used. The wavelength selective switch (WSS) can select the path of the signal light for each wavelength and has a bandwidth variable function and an attenuation amount adjustment function. The second optical signal adjuster 2240 can adapt the respective optical intensities of the first transmission optical signal and the second transmission optical signal to the optical intensity setting information by the attenuation amount adjustment function provided in the wavelength selective switch (WSS).

[0048] Here, since the first optical device 2100 does not include a dummy light generation unit, it is not possible to measure in advance the wavelength dependence of the optical intensity in the undersea optical transmission line 20. Therefore, it is difficult for the first optical device 2100 to acquire the optical intensity setting information by itself. Therefore, the first optical device 2100 alone cannot control the first optical signal adjuster 2110 so that the optical intensity of the transmission optical signal conforms to the optical intensity setting information.

[0049] On the other hand, if the first optical signal adjuster 2110 is not controlled to pass the transmission optical signal, the second optical device 2201 cannot receive the transmission optical signal by the optical monitor unit 2230, so that the optical monitor information cannot be generated. Therefore, in this case, the second optical device 2201 cannot control the second optical signal adjuster 2240 so that the optical intensity of the transmission optical signal conforms to the optical intensity setting information.

[0050] Therefore, in order to realize a function such as inserting a transmission optical signal that compensates for the wavelength dependence of the undersea optical transmission line 20, it is necessary to individually control the first optical device 2100 and the second optical device 2201. Therefore, when the first optical device 2100 and the second optical device 2200 are located separately, such as at a connection point (POP) and a landing station (CLS), complex control is required.

[0051] On the other hand, in the optical transmission system 2001 of the present embodiment, the second control unit 2210 sends transmission optical information to the first control unit 2120, and the first control unit 2120 uses this transmission optical information to cause the transmission optical signal to pass through. The first optical signal adjustment unit 2110 is controlled. Then, the optical monitor unit 2230 receives the transmission optical signal and generates optical monitor information, and the second control unit 2210 uses the optical monitor information to make the optical intensity of the transmission optical signal conform to the optical intensity setting information. The second optical signal adjustment unit 2240 is controlled. Therefore, by simply performing an operation in which an external device such as a monitoring device (EMS) instructs the second optical device 2201 to start operating, a function of automatically inserting a transmission optical signal that conforms to the optical intensity setting information can be realized.

[0052] Next, the operation of the optical transmission system 2001 according to the present embodiment will be specifically described. FIG. 7 is a sequence diagram for explaining the operation of the optical transmission system 2001 according to the present embodiment.

[0053] First, the monitoring device (EMS) sends transmission optical information such as the center wavelength, bandwidth, and connection port number of the optical transponder newly inserted into the first optical device (POP) to the second optical device (CLS) (step S11). The transmission optical information can include an identification code (ID (identification) number) and an IP (Internet Protocal) address of the device for identifying the first optical device (POP).

[0054] The second optical device (CLS) registers the transmission optical information and responds to the monitoring device (EMS) to that effect (step S21).

[0055] Next, the monitoring device (EMS) instructs the execution of the function of automatically inserting a transmission optical signal into the second optical device (CLS) (step S12). As a result, the second optical device (CLS) first sends the transmission optical information to the first optical device (POP) (step S22). The first optical device (POP) sets the first optical signal adjustment unit (WSS) using the transmission optical information and responds to the second optical device (CLS) to that effect (step S31).

[0056] Subsequently, the second optical device (CLS) starts setting the second optical signal adjustment unit (WSS) (step S23). The second optical device (CLS) first acquires optical monitor information using the optical monitor unit (OCM) (step S24). Then, it is determined whether the difference between the optical power of the inserted optical transponder included in the optical monitor information and the target power based on the optical intensity setting information is equal to or less than a predetermined value (step S25). Here, this predetermined value can be, for example, ±5 decibels (dB).

[0057] When the difference between the optical power and the target power is not equal to or less than the predetermined value (step S25 / NO), the second optical device (CLS) adjusts the attenuation amount of the second optical signal adjustment unit (WSS) and resets the second optical signal adjustment unit (WSS) (step S23). When the difference between the optical power and the target power is equal to or less than the predetermined value (step S25 / YES), the second optical device (CLS) completes the setting of the second optical signal adjustment unit (WSS) and notifies the monitoring device (EMS) to that effect (step S26). Thereby, the automatic insertion operation of the transmission optical signal by the optical transmission system 2001 of the present embodiment ends.

[0058] By the above operations, an external device such as the monitoring device (EMS) only needs to perform one operation of instructing the second optical device (CLS) to start the operation, and the function of automatically inserting a transmission optical signal conforming to the optical intensity setting information can be realized. That is, according to the optical transmission system 2001 of the present embodiment, in the optical transmission system, even when the end point of the optical signal propagating through the submarine cable is extended, the control can be simplified.

[0059] Next, the optical transmission method according to this embodiment will be described using the flowchart shown in FIG. 8.

[0060] In the optical transmission method according to this embodiment, first, transmission optical information, which is information regarding a transmission optical signal, is acquired (step S110). Then, by adjusting the optical intensity for each wavelength using this transmission optical information, the transmission optical signal is passed through (step S120).

[0061] The configuration up to this point is the same as the optical transmission method according to the first embodiment. In the optical transmission method of this embodiment, the optical intensity of the received input light is monitored for each wavelength to generate optical monitor information (step S210). Also, optical intensity setting information for compensating the optical transmission characteristics of the undersea optical transmission line through which the transmission optical signal propagates is held (step S220). And the configuration further includes adapting the optical intensity of the transmission optical signal to the optical intensity setting information using the optical monitor information (step S230).

[0062] By adopting such a configuration, a function of automatically inserting a transmission optical signal adapted to the optical intensity setting information can be realized with simple control.

[0063] Here, the configuration can further include generating dummy light. In this case, generating the above-described optical monitor information includes receiving the transmission optical signal and the dummy light and generating first optical monitor information, which is the optical monitor information. Then, the first optical monitor information and the optical intensity setting information are acquired via the optical transmission line, and the configuration can be such that the optical intensity of the transmission optical signal is adapted to the optical intensity setting information using the first optical monitor information. At this time, the optical intensity of the dummy light may be adapted to the optical intensity setting information using the first optical monitor information.

[0064] Also, it may be configured to receive a first transmitted optical signal that is a transmitted optical signal via an optical transmission path, receive a second transmitted optical signal different from the first transmitted optical signal, and multiplex the first transmitted optical signal and the second transmitted optical signal by adjusting their respective optical intensities for each wavelength. Also in this case, it can be configured to further generate dummy light. At this time, generating the above-described optical monitor information includes receiving the first transmitted optical signal, the second transmitted optical signal, and the dummy light, and generating second optical monitor information that is the optical monitor information. Then, using the second optical monitor information, the respective optical intensities of the first transmitted optical signal and the second transmitted optical signal can be configured to conform to the optical intensity setting information. Further, the optical intensity of the dummy light may be configured to conform to the optical intensity setting information using the second optical monitor information.

[0065] Receiving the above-described first transmitted optical signal can include receiving the first transmitted optical signal via an optical transmission path laid on land. Then, a multiplexed optical signal can be generated by adjusting and multiplexing the respective optical intensities of the first transmitted optical signal and the second transmitted optical signal for each wavelength, and this multiplexed optical signal can be sent to a submarine optical transmission path.

[0066] As described above, according to the optical transmission systems 2000 and 2001 and the optical transmission method of the present embodiment, even when the termination point of the optical signal propagating through the submarine cable is extended in the optical transmission system, the control can be simplified.

[0067] Some or all of the above embodiments can be described as follows in the appended claims, but are not limited thereto.

[0068] (Appendix 1) A first optical device including first optical signal adjustment means configured to adjust the optical intensity of an input optical signal for each wavelength, and first control means for controlling the first optical signal adjustment means; and a second optical device including second control means. The second control means sends transmission optical information, which is information about a transmission optical signal, to the first control means. The first control means controls the first optical signal adjustment means to pass the transmission optical signal using the transmission optical information. An optical transmission system.

[0069] (Appendix 2) The optical transmission system according to Appendix 1, wherein the second control means sends the transmission optical information to the first control means via an optical transmission path through which the transmission optical signal propagates from the first optical device to the second optical device.

[0070] (Appendix 3) The second optical device further includes dummy light generation means for generating dummy light, and optical monitor means for monitoring the optical intensity of received input light for each wavelength and generating optical monitor information. The second control means includes storage means configured to store optical intensity setting information for compensating the optical transmission characteristics of a submarine optical transmission path to which the second optical device is connected. The optical transmission system according to Appendix 2.

[0071] (Appendix 4) The optical monitor means receives the transmission optical signal and the dummy light and generates first optical monitor information, which is the optical monitor information. The second control means sends the first optical monitor information and the optical intensity setting information to the first control means via the optical transmission path. The first control means controls the first optical signal adjustment means so that the optical intensity of the transmission optical signal conforms to the optical intensity setting information using the first optical monitor information. The optical transmission system according to Appendix 3.

[0072] (Appendix 5) The optical transmission system according to Appendix 4, wherein the second control means controls the dummy light generation means so that the optical intensity of the dummy light conforms to the optical intensity setting information using the first optical monitor information.

[0073] (Appendix 6) The second optical device receives the first transmission optical signal which is the transmission optical signal from the first optical device, receives a second transmission optical signal from a third optical device, and further has second optical signal adjustment means configured to adjust the optical intensities of each of the first transmission optical signal and the second transmission optical signal for each wavelength and combine them. The optical monitor means receives the first transmission optical signal, the second transmission optical signal, and the dummy light, generates second optical monitor information which is the optical monitor information, and the second control means uses the second optical monitor information to control the second optical signal adjustment means so that the optical intensities of each of the first transmission optical signal and the second transmission optical signal conform to the optical intensity setting information. The optical transmission system described in Appendix 3.

[0074] (Appendix 7) The second control means uses the second optical monitor information to control the dummy light generation means so that the optical intensity of the dummy light conforms to the optical intensity setting information. The optical transmission system described in Appendix 6.

[0075] (Appendix 8) The first optical signal adjustment means includes a first connection port configured to be connected to an optical transponder that generates the transmission optical signal, and a second connection port configured to be connected to the optical transmission line laid on land. The optical transmission system described in any one of Appendices 2 to 7.

[0076] (Appendix 9) The second optical signal adjustment means includes a third connection port configured to be connected to the optical transmission line laid on land, and a fourth connection port configured to be connected to the undersea optical transmission line. The optical transmission system described in Appendix 6 or 7.

[0077] (Appendix 10) The transmission optical information includes at least the center wavelength of the transmission optical signal, the bandwidth, and the connection port number of the first optical signal adjustment means into which the transmission optical signal is introduced. The optical transmission system described in any one of Appendices 1 to 9.

[0078] (Supplementary Note 11) An optical transmission method for obtaining transmission optical information which is information regarding a transmission optical signal, and passing the transmission optical signal by adjusting the optical intensity for each wavelength using the transmission optical information.

[0079] (Supplementary Note 12) The optical transmission method according to Supplementary Note 11, wherein obtaining the transmission optical information includes obtaining the transmission optical information via an optical transmission path through which the transmission optical signal propagates.

[0080] (Supplementary Note 13) The optical transmission method according to Supplementary Note 12, further comprising monitoring the optical intensity of received input light for each wavelength to generate optical monitor information, and holding optical intensity setting information for compensating the optical transmission characteristics of a submarine optical transmission path through which the transmission optical signal propagates.

[0081] (Supplementary Note 14) The optical transmission method according to Supplementary Note 13, further comprising generating dummy light, wherein generating the optical monitor information includes receiving the transmission optical signal and the dummy light to generate first optical monitor information which is the optical monitor information, obtaining the first optical monitor information and the optical intensity setting information via the optical transmission path, and adapting the optical intensity of the transmission optical signal to the optical intensity setting information using the first optical monitor information.

[0082] (Supplementary Note 15) The optical transmission method according to Supplementary Note 14, wherein the optical intensity of the dummy light is adapted to the optical intensity setting information using the first optical monitor information.

[0083] (Appendix 16) Further comprising generating dummy light, receiving a first transmission optical signal which is the transmission optical signal via the optical transmission path, receiving a second transmission optical signal different from the first transmission optical signal, and multiplexing by adjusting respective optical intensities of the first transmission optical signal and the second transmission optical signal for each wavelength, wherein generating the optical monitor information includes receiving the first transmission optical signal, the second transmission optical signal, and the dummy light, and generating second optical monitor information which is the optical monitor information, and using the second optical monitor information to adapt respective optical intensities of the first transmission optical signal and the second transmission optical signal to optical intensity setting information. The optical transmission method described in Appendix 13.

[0084] (Appendix 17) The optical transmission method described in Appendix 16, further comprising using the second optical monitor information to adapt the optical intensity of the dummy light to the optical intensity setting information.

[0085] (Appendix 18) Passing the transmission optical signal includes receiving the transmission optical signal from an optical transponder and sending the transmission optical signal to the optical transmission path laid on land. The optical transmission method described in any one of Appendices 12 to 17.

[0086] (Appendix 19) Receiving the first transmission optical signal includes receiving the first transmission optical signal via the optical transmission path laid on land, generating a multiplexed optical signal by adjusting respective optical intensities of the first transmission optical signal and the second transmission optical signal for each wavelength and multiplexing them, and sending the multiplexed optical signal to the undersea optical transmission path. The optical transmission method described in Appendix 16 or 17.

[0087] (Appendix 20) The transmission optical information includes at least a center wavelength and a bandwidth of the transmission optical signal. The optical transmission method described in any one of Appendices 11 to 19.

[0088] The present invention has been described with reference to the embodiments above, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

Description of Symbols

[0089] 1000, 2000, 2001 Optical Transmission Systems 1100, 2100 First Optical Devices 1110, 2110 First Optical Signal Adjustment Units 1120, 2120 First Control Units 1200, 2200, 2201 Second Optical Devices 1210, 2210 Second Control Units 2211 Memory Unit 2220 Dummy Light Generation Unit 2230 Optical Monitor Unit 2240 Second Optical Signal Adjustment Unit 3000 Third Optical Device 10 Optical Transmission Line 20 Submarine Optical Transmission Line

Claims

1. a first optical signal adjustment means configured to adjust the optical intensity of an input optical signal for each wavelength; a first optical device comprising the first optical signal adjustment means and a first control means for controlling the first optical signal adjustment means; a second optical device comprising a second control means; wherein the second control means sends transmission optical information, which is information regarding the transmission optical signal, to the first control means; the first control means controls the first optical signal adjustment means to pass the transmission optical signal using the transmission optical information; the second control means sends the transmission optical information to the first control means via an optical transmission path through which the transmission optical signal propagates from the first optical device to the second optical device; the second optical device further comprises a dummy light generation means for generating dummy light; and an optical monitor means for monitoring the optical intensity of the received input light for each wavelength and generating optical monitor information; the second control means comprises a storage means configured to store optical intensity setting information for compensating the optical transmission characteristics of the undersea optical transmission path to which the second optical device is connected optical transmission system.

2. the optical monitor means receives the transmission optical signal and the dummy light and generates first optical monitor information, which is the optical monitor information; the second control means sends the first optical monitor information and the optical intensity setting information to the first control means via the optical transmission path; the first control means controls the first optical signal adjustment means so that the optical intensity of the transmission optical signal conforms to the optical intensity setting information using the first optical monitor information The optical transmission system according to claim 1.

3. the second control means controls the dummy light generation means so that the optical intensity of the dummy light conforms to the optical intensity setting information using the first optical monitor information The optical transmission system according to claim 2.

4. the second optical device further comprises a second optical signal adjustment means configured to receive the first transmission optical signal, which is the transmission optical signal, from the first optical device, receive a second transmission optical signal from a third optical device, and adjust and multiplex the optical intensities of the first transmission optical signal and the second transmission optical signal for each wavelength; the optical monitor means receives the first transmission optical signal, the second transmission optical signal, and the dummy light and generates second optical monitor information, which is the optical monitor information The second control means controls the second optical signal adjustment means using the second optical monitor information so that the optical intensities of the first transmission optical signal and the second transmission optical signal conform to the optical intensity setting information. The optical transmission system according to claim 1.

5. The second control means controls the dummy light generation means using the second optical monitor information so that the optical intensity of the dummy light conforms to the optical intensity setting information. The optical transmission system according to claim 4.

6. The first optical signal adjustment means comprises a first connection port configured to be connected to an optical transponder that generates the transmission optical signal, and a second connection port configured to be connected to the optical transmission line laid on land. The optical transmission system according to any one of claims 1 to 5.

7. The second optical signal adjustment means comprises a third connection port configured to be connected to the optical transmission line laid on land, and a fourth connection port configured to be connected to the undersea optical transmission line. The optical transmission system according to claim 4 or 5.

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