OPTICAL TRANSMISSION SYSTEM, OPTICAL DEVICE, OPTICAL NETWORK MANAGEMENT DEVICE, AND OPTICAL TRANSMISSION METHOD

Abstract

In a case where a failure occurs in a part of an optical fiber in an optical cable, when attempting to switch to a redundant configuration, the stable use of an optical transmission system is impaired, so that the wavelength band cannot be used effectively. Accordingly, the optical transmission system of the present invention includes a first optical device that changes the transmission line of a wavelength band signal propagating through a first optical transmission line to a second optical transmission line that is the same path as the first optical transmission line, in the stage before a faulty part in the first optical transmission line, and a second optical device that changes the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line, in the stage after the faulty part.

Description

[Technical Field]

[0001] The present invention relates to an optical transmission system, an optical device, and an optical transmission method, and more particularly to an optical transmission system, an optical device, and an optical transmission method used in an optical submarine cable transmission system. [Background technology]

[0002] Optical submarine cable transmission systems, which connect continents with optical fiber, play an important role as infrastructure supporting international communication networks. Optical submarine cable transmission systems consist of submarine cables that accommodate optical fiber, submarine repeaters equipped with optical amplifiers, submarine branching equipment that branches optical signals, and terminal equipment installed at landing stations. The terminal equipment includes wavelength multiplexing equipment (WME), submarine line termination equipment (SLTE), and system monitoring equipment.

[0003] Since optical submarine cable transmission systems handle large-volume traffic, there is an increasing importance of technology for quickly recovering from communication failures caused by optical fiber disconnections, undersea equipment failures, etc. An example of a failure recovery technology for such optical submarine cable transmission systems is described in Patent Document 1.

[0004] The related optical submarine cable system described in Patent Document 1 has a configuration in which related optical devices are connected in a mesh pattern by submarine cables. The related optical devices include optical add / drop circuits, optical path break detectors, and optical splitters. When the related optical devices detect a loss of an optical signal, they change the settings of the optical add / drop circuits to bypass the section where the signal has been lost. In other words, the related optical submarine cable system is configured to set up a detour route by switching the route on a submarine cable basis when a fault occurs on the route.

[0005] Further, related techniques include those described in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 006861 [Patent Document 2] Special Publication No. 2019-517169 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-088606 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the spread of cloud services has led to an increase in communication traffic between data centers (DCs) located around the world. As a result, cloud service providers other than telecommunications carriers have begun to directly invest in optical submarine cable transmission systems. As a result, there are cases where different users are involved in each optical fiber housed in a submarine cable or each wavelength band of the optical fiber.

[0008] In addition, submarine branching equipment has also been equipped with a Reconfigurable Optical Add / Drop Multiplexer (ROADM) function that switches the optical signal path on a wavelength-by-wavelength basis, and is equipped with a Wavelength Selectable Switch (WSS). Therefore, a failure in a WSS or other device can cause problems such as communication interruptions or degradation of transmission quality in only certain wavelength bands.

[0009] In such a case, if the route is switched on an optical cable basis or on an optical fiber contained in an optical cable basis in order to recover from the failure, as in the related optical submarine cable system described above, the following problems will arise.

[0010] When a fault occurs in one of the optical fibers in an optical cable, switching the optical cable (route) to a redundant configuration also requires switching the optical cable (route) of the optical fiber that is not faulty. This changes the optical transmission conditions and requires changing the optical transmission equipment installed in the terminal device. This is an unnecessary change for other users who use the optical fiber that is not faulty, and it causes a problem of impairing stable use of the optical transmission system. Furthermore, since the optical fiber that is not faulty is not used even though it is still usable, it causes a problem of ineffective use of the optical fiber wavelength band.

[0011] Furthermore, if a fault occurs in a wavelength band of an optical fiber, switching to a redundant configuration for each optical fiber housed in the optical cable will also result in switching to the optical fiber for optical signals in the normal wavelength band. This requires changing the optical transmission equipment installed in the terminal equipment. In this case, too, this change is unnecessary for other users using the normal wavelength band, and the stable use of the optical transmission system is impaired. Furthermore, since the normal wavelength band of the optical fiber will not be used even though it is still available, the wavelength band will not be used effectively.

[0012] In this way, if a fault occurs in part of an optical fiber in an optical cable, switching to a redundant configuration would impair stable use of the optical transmission system and prevent effective use of the wavelength band.

[0013] An object of the present invention is to provide an optical transmission system, an optical device, an optical network management device, and an optical transmission method that solve the above-mentioned problems. [Means for solving the problem]

[0014] The optical transmission system of the present invention includes a first optical device that changes the transmission path of a wavelength band signal propagating through a first optical transmission path to a second optical transmission path having the same route as the first optical transmission path, upstream of a fault location in the first optical transmission path, and a second optical device that changes the transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path, downstream of the fault location.

[0015] The optical device of the present invention has a switching means that performs either a first switching process or a second switching process, an input connection means that connects each of a first optical transmission line and a second optical transmission line that is the same route as the first optical transmission line to the input side of the switching means, and an output connection means that connects each of the first optical transmission line and the second optical transmission line to the output side of the switching means, wherein the first switching process is a process of changing the transmission line of a wavelength band signal propagating through the first optical transmission line to the second optical transmission line at a stage upstream of a fault location in the first optical transmission line, and the second switching process is a process of changing the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line at a stage downstream of the fault location.

[0016] The optical network management device of the present invention comprises a monitoring means for monitoring the occurrence of a fault in a first optical transmission line and, when the occurrence of a fault is detected, generating fault occurrence information; and a control means for, based on the fault occurrence information, instructing a first optical device located upstream of the location where the fault occurred to change the transmission line of the wavelength band signal propagating through the first optical transmission line to a second optical transmission line having the same route as the first optical transmission line, and instructing a second optical device located downstream of the location where the fault occurred to change the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line.

[0017] The optical transmission method of the present invention changes the transmission path of a wavelength band signal propagating through a first optical transmission path to a second optical transmission path having the same route as the first optical transmission path, upstream of a fault location in the first optical transmission path, and changes the transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path, downstream of the fault location.

[0018] The optical transmission method of the present invention propagates a first wavelength-multiplexed optical signal through a first optical transmission path, and propagates a second wavelength-multiplexed optical signal through a second optical transmission path that is the same route as the first optical transmission path, and if a fault occurs in the first optical transmission path, stops propagation of the second wavelength-multiplexed optical signal upstream of the location where the fault occurred, and changes the transmission path of the wavelength band signals that make up the first wavelength-multiplexed optical signal to the second optical transmission path, and changes the transmission path of the wavelength band signals from the second optical transmission path to the first optical transmission path downstream of the location where the fault occurred. [Effects of the Invention]

[0019] According to the optical transmission system, optical device, optical network management device, and optical transmission method of the present invention, even if a fault occurs in part of an optical fiber in an optical cable, fault recovery can be achieved while effectively utilizing the wavelength band without impairing stable use of the optical transmission system. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a block diagram showing a configuration of an optical transmission system according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram showing a configuration of an optical transmission system according to a first embodiment of the present invention, illustrating a case where, in addition to a wavelength band signal, another wavelength band signal propagates through a first optical transmission line. [Figure 3] 1 is a block diagram showing a configuration of an optical device according to a first embodiment of the present invention. [Figure 4] 1 is a block diagram showing a configuration of an optical network management device according to a first embodiment of the present invention. [Figure 5] FIG. 10 is a diagram illustrating the operation of the optical transmission system according to the second embodiment of the present invention. [Figure 6] FIG. 10 is a diagram illustrating another operation of the optical transmission system according to the second embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating the operation of the optical transmission system according to the third embodiment of the present invention. [Figure 8]FIG. 10 is a diagram for explaining the operation of the optical transmission system according to the third embodiment of the present invention, showing a case where a failure such as communication interruption or deterioration in transmission quality occurs only in a part of wavelength bands. [Figure 9] FIG. 10 is a diagram illustrating another operation of the optical transmission system according to the third embodiment of the present invention. [Figure 10A] 3A to 3C are diagrams for explaining the operations of the first and second optical devices according to the embodiment of the present invention. [Figure 10B] 10A and 10B are diagrams for explaining other operations of the first optical device and the second optical device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] [First embodiment] 1 is a block diagram showing the configuration of an optical transmission system 1000 according to a first embodiment of the present invention. The optical transmission system 1000 includes a first optical device 1110 and a second optical device 1120.

[0023] The first optical device 1110, at a stage upstream of the fault location 100 in the first optical transmission line 110, changes the transmission path of the wavelength band signal S100 propagating through the first optical transmission line 110 to a second optical transmission line 120 that is the same route as the first optical transmission line 110. The second optical device 1120, at a stage downstream of the fault location 100, changes the transmission path of the wavelength band signal S100 from the second optical transmission line 120 to the first optical transmission line 110.

[0024] With this configuration, in the optical transmission system 1000 of this embodiment, the wavelength band signal S100 propagates, bypassing the fault location 100 only between the first optical device 1110 and the second optical device 1120. Therefore, there is no need to change the optical transmission devices provided in the terminal devices connected to the first optical device 1110 and the second optical device 1120.

[0025] That is, the optical transmission system 1000 is configured such that after the first optical device 1110 switches the transmission path of the wavelength band signal S100, the second optical device 1120 switches it back to the original transmission path. Therefore, by bypassing the fault location 100, the wavelength band signal S100 is not placed on the other transmission path side in the terminal device. As a result, even if the users of the first optical transmission path 110 and the second optical transmission path 120 are different, user security can be ensured.

[0026] In this way, the optical transmission system 1000 can achieve failure recovery without impairing stable use of the optical transmission system.

[0027] As described above, in the optical transmission system 1000, the first optical device 1110 switches from the first optical transmission path 110 to the second optical transmission path 120 at a stage upstream of the fault location 100 in the first optical transmission path 110. Then, the second optical device 1120 switches back to the first optical transmission path 110 at a stage downstream of the fault location 100. Therefore, at the stage upstream of the first optical device 1110 and the stage downstream of the second optical device 1120, the second optical transmission path 120, which serves as a detour for the fault location 100, can be used as a transmission path for signals in other wavelength bands. As a result, it is possible to recover from the fault while effectively utilizing the wavelength bands.

[0028] Here, the first optical transmission line 110 and the second optical transmission line 120 are typically configured by optical fibers. The first optical transmission line 110 and the second optical transmission line 120 can be configured as the same route, for example, by being housed in the same optical cable. Furthermore, both the first optical transmission line 110 and the second optical transmission line 120 may be optical fibers for upstream lines, and may each form a fiber pair (FP) together with an optical fiber for downstream lines (not shown).

[0029] The first optical transmission line 110 is an operating optical fiber through which an operating optical signal propagates, and the second optical transmission line 120 may be a backup (spare) optical fiber for bypassing in the event of a fault. Note that, under normal circumstances (when a fault does not occur), the second optical transmission line 120 is used as an operating optical fiber, thereby enabling an increase in transmission capacity.

[0030] 1 shows only wavelength band signal S100, but as shown in Fig. 2, other wavelength band signals may propagate through the first optical transmission line 110 in addition to wavelength band signal S100. For example, wavelength band signal S100 may be at least a part of a plurality of wavelength band signals constituting a wavelength division multiplexing (WDM) optical signal.

[0031] Furthermore, when the first optical transmission line 110 includes a plurality of first optical fibers and a fault occurs in one of the plurality of first optical fibers, the first optical device 1110 can be configured to operate as follows.

[0032] That is, the first optical device 1110 determines a priority optical fiber from among the plurality of first optical fibers based on the priorities of the plurality of first optical fibers. Then, the first optical device 1110 changes the transmission path of the wavelength band signal S100 propagating through this priority optical fiber to the second optical transmission path 120. Here, the first optical device 1110 can determine the first optical fiber from among the plurality of first optical fibers that has detected a signal interruption earliest as the priority optical fiber, as the first optical fiber with the highest priority. However, without being limited to this, a first optical fiber with a preset high priority may be determined as the priority optical fiber.

[0033] Furthermore, when the second optical transmission line 120 includes a plurality of second optical fibers, the first optical device 1110 can be configured to operate as follows.

[0034] That is, the first optical device 1110 determines a low-priority optical fiber among the plurality of second optical fibers based on the priorities of the plurality of second optical fibers, and changes the transmission path of the wavelength band signal S100 to this low-priority optical fiber. In this case, it is possible to achieve failure recovery without providing a backup (spare) optical fiber as the second optical transmission path 120 for bypassing in case of a failure.

[0035] Next, the optical device according to this embodiment will be described. Fig. 3 shows the configuration of an optical device 1100 according to this embodiment.

[0036] An optical device 1100 according to this embodiment has a switching unit (switching means) 1101 that performs either a first switching process or a second switching process, an input connection unit (input connection means) 1102, and an output connection unit (output connection means) 1103. The input connection unit 1102 connects a first optical transmission line 110 and a second optical transmission line 120 that has the same path as the first optical transmission line 110 to the input side of the switching unit (switching means) 1101. The output connection unit 1103 connects the first optical transmission line 110 and the second optical transmission line 120 to the output side of the switching unit (switching means) 1101.

[0037] Here, the first switching process is a process of changing the transmission path of the wavelength band signal propagating through the first optical transmission path 110 to the second optical transmission path 120 at a stage preceding the fault location in the first optical transmission path 110. The second switching process is a process of changing the transmission path of the wavelength band signal from the second optical transmission path 120 to the first optical transmission path at a stage following the fault location.

[0038] The switching unit 1101 can typically be configured to include a wavelength selectable switch (WSS). The optical device 1100 includes submarine equipment used in an optical submarine cable transmission system, such as an optical branching device, a transmission device, a repeater, etc.

[0039] The optical device 1100 may further include a control unit (control means) that determines a priority optical fiber based on the priorities of the multiple first optical fibers among the multiple first optical fibers included in the first optical transmission path 110. In this case, the switching unit 1101 changes the transmission path of the wavelength band signal propagating through the priority optical fiber to the second optical transmission path 120 in the first switching process.

[0040] Furthermore, the control unit (control means) may determine a low-priority optical fiber based on the priorities of a plurality of second optical fibers among a plurality of second optical fibers included in the second optical transmission path 120. In this case, the switching unit 1101 changes the transmission path of the wavelength band signal to the low-priority optical fiber in the first switching process.

[0041] Next, the optical network management device according to this embodiment will be described. Fig. 4 shows the configuration of an optical network management device 1200 according to this embodiment.

[0042] The optical network management device 1200 includes a monitoring unit (monitoring means) 1210 and a control unit (control means) 1220 .

[0043] The monitoring unit 1210 monitors the occurrence of a fault in the first optical transmission line, and generates fault occurrence information when the occurrence of a fault is detected. Based on this fault occurrence information, the control unit 1220 instructs a first optical device located upstream of the location where the fault occurred to change the transmission path of the wavelength band signal propagating through the first optical transmission line to a second optical transmission line that is the same route as the first optical transmission line. The control unit 1220 further instructs a second optical device located downstream of the location where the fault occurred to change the transmission path of the wavelength band signal from the second optical transmission line to the first optical transmission line.

[0044] Next, the optical transmission method according to this embodiment will be described.

[0045] In the optical transmission method according to this embodiment, first, at a stage upstream of a fault location in a first optical transmission line, the transmission line of a wavelength band signal propagating through the first optical transmission line is changed to a second optical transmission line that is the same route as the first optical transmission line, and then, at a stage downstream of the fault location, the transmission line of the wavelength band signal is changed from the second optical transmission line to the first optical transmission line.

[0046] Here, the process of changing the transmission path to the second optical transmission path may include the following process: determining a priority optical fiber among a plurality of first optical fibers included in the first optical transmission path based on the priorities of the plurality of first optical fibers, and changing the transmission path of the wavelength band signal propagating through this priority optical fiber to the second optical transmission path.

[0047] Furthermore, when changing the above-mentioned transmission path to a second optical transmission path, a low-priority optical fiber may be determined based on the priorities of the second optical fibers among the second optical fibers included in the second optical transmission path, and the transmission path of the wavelength band signal may be changed to the low-priority optical fiber.

[0048] In another optical transmission method according to this embodiment, first, a first wavelength-multiplexed optical signal is propagated through a first optical transmission line, and a second wavelength-multiplexed optical signal is propagated through a second optical transmission line that is the same route as the first optical transmission line. If a fault occurs in the first optical transmission line, propagation of the second wavelength-multiplexed optical signal is stopped upstream of the fault, and the transmission line of the wavelength band signals that make up the first wavelength-multiplexed optical signal is changed to the second optical transmission line. Furthermore, downstream of the fault, the transmission line of the wavelength band signals is changed from the second optical transmission line to the first optical transmission line.

[0049] As described above, according to the optical transmission system 1000, optical device 1100, optical network management device 1200, and optical transmission method of this embodiment, even if a fault occurs in part of an optical fiber in an optical cable, fault recovery can be achieved while effectively utilizing the wavelength band without impairing stable use of the optical transmission system.

[0050] Second Embodiment Next, a second embodiment of the present invention will be described. As shown in Fig. 5, the configuration of an optical transmission system 2000 according to this embodiment is similar to the configuration of the optical transmission system 1000 according to the first embodiment, and includes a first optical device 2110 and a second optical device 2120.

[0051] The first optical device 2110, at a stage upstream of the fault location 100 in the first optical transmission line 110, changes the transmission path of the wavelength band signal propagating through the first optical transmission line 110 to a second optical transmission line 120 that is the same route as the first optical transmission line 110. At this time, the first optical device 2110 of this embodiment determines a priority band signal S11 as a wavelength band signal based on the priorities of multiple first wavelength band signals among multiple first wavelength band signals that constitute the first wavelength multiplexed optical signal S210 propagating through the first optical transmission line 110. Then, the first optical device 2110 changes the transmission path of this priority band signal S11 to the second optical transmission line 120.

[0052] The second optical device 2120 changes the transmission path of the priority band signal S11 from the second optical transmission path 120 to the first optical transmission path 110 at the downstream side of the fault location 100.

[0053] Here, the priority can be defined by a plurality of priority levels, for example, three levels of low, medium, and high, or five levels of 1, 2, 3, 4, and 5. The first optical device 2110 can be configured to give priority to wavelength band signals with higher priority levels and change their transmission paths. However, the first optical device 2110 may also give priority to wavelength band signals with a medium priority level and change their transmission paths. In this way, the order in which the transmission paths of the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal S210 are changed can be determined based on the priority.

[0054] Here, only the priority band signal S11 determined based on the priority propagates through the second optical transmission line 120. Therefore, even in the section corresponding to the fault location 100 (between the first optical device 2110 and the second optical device 2120), the second optical transmission line 120 can be used as a transmission signal band for wavelength bands other than the wavelength band occupied by the priority band signal S11. As a result, fault recovery can be achieved while making more effective use of the wavelength band.

[0055] 6, the optical transmission system 2001 may be configured such that the first optical device 2110 maps a wavelength band signal propagating through the first optical transmission line 110 to a portion of the wavelength band of the second wavelength multiplexed optical signal S220 propagating through the second optical transmission line 120. In this case, the first optical device 2110 determines a low-priority band B21 based on the priorities of the second wavelength band signals among the second wavelength bands occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal S220 propagating through the second optical transmission line 120. The first optical device 2110 may then map the wavelength band signal propagating through the first optical transmission line 110 to the low-priority band B21. FIG. 6 shows an example in which the above-described priority band signal S11 is mapped to the low-priority band B21 as the wavelength band signal.

[0056] The low-priority band includes an unused band that is not occupied by the second wavelength band signal that constitutes the second wavelength multiplexed optical signal S220.

[0057] As described above, the optical transmission systems 2000 and 2001 according to this embodiment are configured such that, after the first optical device 2110 switches the transmission path of the priority band signal S11, the second optical device 2120 switches it back to the original transmission path. Therefore, by bypassing the fault location 100, the priority band signal S11 is not placed on another transmission path in the terminal device. As a result, even if the users of the first optical transmission path 110 and the second optical transmission path 120 are different, user security can be ensured.

[0058] In this way, the optical transmission systems 2000 and 2001 can achieve failure recovery without impairing stable use of the optical transmission system.

[0059] Next, the optical device according to this embodiment will be described. The configuration of the optical device according to this embodiment is similar to the configuration of the optical device 1100 according to the first embodiment shown in FIG.

[0060] That is, the optical device according to this embodiment has a switching unit 1101 that performs either a first switching process or a second switching process, an input connection unit 1102, and an output connection unit 1103. The input connection unit 1102 connects the first optical transmission path 110 and the second optical transmission path 120, which has the same path as the first optical transmission path 110, to the input side of the switching unit 1101. The output connection unit 1103 connects the first optical transmission path 110 and the second optical transmission path 120 to the output side of the switching unit 1101.

[0061] Here, the first switching process is a process of changing the transmission path of the wavelength band signal propagating through the first optical transmission path 110 to the second optical transmission path 120 at a stage preceding the fault location in the first optical transmission path 110. The second switching process is a process of changing the transmission path of the wavelength band signal from the second optical transmission path 120 to the first optical transmission path at a stage following the fault location.

[0062] The optical device of this embodiment is configured to further include a control unit (control means) that determines a priority band signal as a wavelength band signal based on the priorities of a plurality of first wavelength band signals among a plurality of first wavelength band signals that constitute a first wavelength multiplexed optical signal propagating through the first optical transmission line 110. In this case, the switching unit 1101 changes the transmission line of this priority band signal to the second optical transmission line 120 in the first switching process.

[0063] Furthermore, the control unit (control means) may determine a low-priority band based on the priorities of the second wavelength band signals among the second wavelength bands occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal propagating through the second optical transmission line 120. In this case, the switching unit 1101 allocates the wavelength band signals to the low-priority band having a low priority in the first switching process. Note that the low-priority band includes an unused band that is not occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal.

[0064] Next, the optical transmission method according to this embodiment will be described.

[0065] In the optical transmission method according to this embodiment, first, at a stage upstream of a fault location in a first optical transmission line, the transmission line of a wavelength band signal propagating through the first optical transmission line is changed to a second optical transmission line that is the same route as the first optical transmission line, and then, at a stage downstream of the fault location, the transmission line of the wavelength band signal is changed from the second optical transmission line to the first optical transmission line.

[0066] In the optical transmission method according to this embodiment, the process of changing the transmission path to the second optical transmission path includes the following process: Among the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal propagating through the first optical transmission path, a priority band signal is determined as a wavelength band signal based on the priorities of the plurality of first wavelength band signals, and the transmission path of the priority band signal is changed to the second optical transmission path.

[0067] Furthermore, the process of changing the transmission path to the second optical transmission path may include the following process. That is, among the second wavelength bands occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal propagating through the second optical transmission path, a low-priority band may be determined based on the priorities of the second wavelength band signals, and the wavelength band signals may be allocated to the low-priority band. Note that the low-priority band includes an unused band that is not occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal.

[0068] As described above, according to the optical transmission systems 2000, 2001, optical devices, and optical transmission methods of this embodiment, even if a fault occurs in part of an optical fiber in an optical cable, fault recovery can be achieved while effectively utilizing the wavelength band without impairing stable use of the optical transmission system.

[0069] Third Embodiment Next, a third embodiment of the present invention will be described. The configuration of an optical transmission system 3000 according to this embodiment is similar to the configuration of the optical transmission system 1000 according to the first embodiment.

[0070] In this embodiment, as shown in Fig. 7, an example will be described in which an optical transmission system 3000 includes a first optical device 3111 and a first optical device 3112 as first optical devices, and a second optical device 3120. Also, the first optical transmission path will be described as including a plurality of first optical fibers 111 and 112, and a fault location 101 exists on the first optical fiber 111 between the first optical device 3111 and the first optical device 3112, and a fault location 102 exists within the first optical device 3112. Note that the fault locations 101 and 102 also include cases in which a fault such as communication interruption or transmission quality degradation occurs only in a part of the wavelength bands, as shown in Fig. 8.

[0071] The first optical device 3111 changes the transmission path of the wavelength band signal propagating through the first optical fiber 111 to the second optical transmission path 120, which is the same path as the first optical fiber 111, at a stage upstream of the fault location 101 in the first optical fiber 111 serving as the first optical transmission path. In addition, the first optical device 3112 changes the transmission path of the wavelength band signal propagating through the first optical fiber 112 to the second optical transmission path 120, which is the same path as the first optical fiber 112, at a stage upstream of the fault location 102 in the first optical fiber 112 serving as the first optical transmission path.

[0072] The second optical device 3120 changes the transmission path of the wavelength band signal from the second optical transmission path to the first optical fiber 111 and the first optical fiber 112 as the first optical transmission path at the downstream of the fault location 101 and the fault location 102.

[0073] Here, the first optical device determines a priority band signal as a wavelength band signal for each of the plurality of first optical fibers based on the priority of the plurality of first wavelength band signals among the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal propagating through each of the plurality of first optical fibers, and then changes the transmission path of each of the priority band signals to the second optical transmission path.

[0074] 7, the first optical device 3111 determines a priority band signal S31 as a wavelength band signal in the first optical fiber 111 from among a plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal S311 propagating through the first optical fiber 111. At this time, the first optical device 3111 determines the priority band signal S31 based on the priorities of the plurality of first wavelength band signals. Then, the first optical device 3111 changes the transmission path of the priority band signal S31 to the second optical transmission path 120. Meanwhile, the second optical device 3120, at a stage subsequent to the fault location 101, changes the transmission path of the priority band signal S31 from the second optical transmission path 120 to the first optical fiber 111 included in the first optical transmission path.

[0075] Furthermore, the first optical device 3112 determines a priority band signal S32 as a wavelength band signal in the first optical fiber 112 from among a plurality of second wavelength band signals constituting the second wavelength multiplexed optical signal S312 propagating through the first optical fiber 112. At this time, the first optical device 3112 determines the priority band signal S32 based on the priorities of the plurality of second wavelength band signals. Then, the first optical device 3112 changes the transmission path of the priority band signal S32 to the second optical transmission path 120. Meanwhile, the second optical device 3120, at a stage subsequent to the fault location 102, changes the transmission path of the priority band signal S32 from the second optical transmission path 120 to the first optical fiber 112 included in the first optical transmission path.

[0076] In this way, according to the optical transmission system 3000 of this embodiment, for example, if a fault occurs in each of the multiple operating optical fibers through which the operating optical signal propagates, it becomes possible to switch the wavelength band signal with a higher priority setting among the wavelength band signals propagating through each operating optical fiber to a backup (spare) optical fiber and propagate it.

[0077] This priority is defined by a plurality of priority levels, for example, three levels of low, medium, and high, or five levels of 1, 2, 3, 4, and 5. The first optical devices 3111 and 3112 can be configured to give priority to wavelength band signals with higher priority levels and change their transmission paths. However, the first optical devices 3111 and 3112 may also give priority to wavelength band signals with a medium priority level and change their transmission paths. In this way, the order in which the transmission paths of a plurality of wavelength band signals are changed can be determined based on the priority.

[0078] In the optical transmission system 3000 according to this embodiment, only the priority band signals S31 and S32 determined based on the priority are propagated through the second optical transmission line 120. Therefore, even in the section corresponding to the fault locations 101 and 102 (between the first optical device 3111 and the second optical device 3120), wavelength bands other than those occupied by the priority band signals S31 and S32 can be used as the transmission signal bands in the second optical transmission line 120. As a result, fault recovery can be achieved while more effectively utilizing the wavelength bands.

[0079] Here, the priority band signals S31, S32 propagating through each of the multiple first optical fibers 111, 112 can be configured to occupy wavelength bands that do not overlap with each other on the frequency axis. That is, in the first wavelength multiplexed optical signal S311 and the second wavelength multiplexed optical signal S312, for example, the priority band signals S31 and S32 with higher priorities can be assigned to wavelength bands that do not overlap with each other on the frequency axis. This makes it possible to transmit the wavelength band signals with higher priorities among the wavelength band signals propagating through each optical transmission path, even if a failure occurs in a plurality of optical transmission paths.

[0080] Furthermore, when a fault occurs in a plurality of operating optical fibers through which operating optical signals propagate, a priority band signal having a high priority setting among the wavelength multiplexed optical signals propagating through each operating optical fiber may be allocated to a low-priority band having a low priority among the wavelength bands of other operating optical fibers. The operation of the optical transmission system 3001 in such a case will be described with reference to FIG.

[0081] The first optical device 3111 changes the transmission path of, for example, priority band signals S31A and S31B having high priority among the multiple first wavelength band signals constituting the first wavelength multiplexed optical signal S311 propagating through the first optical fiber 111 to another first optical fiber 112. At this time, the first optical device 3111 allocates the priority band signals S31A and S31B to a low-priority band B12 having low priority among the wavelength bands occupied by the second wavelength multiplexed optical signal S312 propagating through the first optical fiber 112. As a result, in the first optical fiber 112, in addition to the priority band signals S32A and S32B included in the second wavelength multiplexed optical signal S312 propagating through the first optical fiber 112, the priority band signals S31A and S31B are propagating in the upstream stage of the first optical device 3112.

[0082] Furthermore, the first optical device 3112 changes the transmission path of the priority band signals S31A, S31B, S32A, and S32B to a second optical transmission path upstream of the fault location 102. Here, a case will be described in which the second optical transmission path includes a plurality of second optical fibers 121 and 122 as shown in FIG.

[0083] The first optical device 3112 determines a low-priority band from among the second wavelength bands occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal propagating through each of the second optical fibers 121 and 122. At this time, the first optical device 3112 determines the low-priority band for each of the second optical fibers based on the priorities of the second wavelength band signals. Fig. 9 shows an example in which the first optical device 3112 determines the low-priority band B21 for the second optical fiber 121 and the low-priority band B22 for the second optical fiber 122.

[0084] The first optical device 3112 then allocates the priority band signals as wavelength band signals to the low-priority band. In the example shown in Fig. 9, the first optical device 3112 allocates the priority band signals S31A and S32B to the low-priority band B21 of the second optical fiber 121, and allocates the priority band signals S31B and S32A to the low-priority band B22 of the second optical fiber 122. In this way, the priority band signals S31A, S31B, S32A, and S32B can be optimally allocated to the low-priority bands B21 and B22 of the second optical fibers 121 and 122, which are the destinations of the transmission path change. Note that the low-priority band includes unused bands that are not occupied by wavelength band signals.

[0085] On the other hand, the second optical device 3120 changes the transmission path of the priority band signal, which is a wavelength band signal, from the second optical transmission path to the first optical transmission path downstream of the fault locations 101 and 102. In the example shown in Fig. 9, the second optical device 3120 changes the transmission path of the priority band signals S31A and S31B from the second optical fibers 121 and 122 to the original first optical fiber 111. In addition, the second optical device 3120 changes the transmission path of the priority band signals S32A and S32B from the second optical fibers 121 and 122 to the original first optical fiber 112.

[0086] As described above, in the optical transmission systems 3000 and 3001 according to the present embodiment, the first optical devices 3111 and 3112 switch the transmission path of the priority band signal upstream of the fault locations 101 and 102. Thereafter, the second optical device 3120 switches the transmission path back to the original transmission path downstream of the fault locations 101 and 102. Therefore, by bypassing the fault locations 101 and 102, the priority band signal is not routed to another transmission path in the terminal device. As a result, user security can be ensured even when the first optical fibers 111 and 112 and the second optical fibers 121 and 122 are used by different users.

[0087] In this way, the optical transmission systems 3000 and 3001 can achieve failure recovery without impairing stable use of the optical transmission system.

[0088] Next, the optical device according to this embodiment will be described. The configuration of the optical device according to this embodiment is similar to the configuration of the optical device 1100 according to the first embodiment shown in FIG.

[0089] That is, the optical device according to this embodiment has a switching unit 1101 that performs either a first switching process or a second switching process, an input connection unit 1102, and an output connection unit 1103. The input connection unit 1102 connects the first optical transmission path 110 and the second optical transmission path 120, which has the same path as the first optical transmission path 110, to the input side of the switching unit 1101. The output connection unit 1103 connects the first optical transmission path 110 and the second optical transmission path 120 to the output side of the switching unit 1101.

[0090] Here, the first switching process is a process of changing the transmission path of the wavelength band signal propagating through the first optical transmission path 110 to the second optical transmission path 120 at a stage preceding the fault location in the first optical transmission path 110. The second switching process is a process of changing the transmission path of the wavelength band signal from the second optical transmission path 120 to the first optical transmission path at a stage following the fault location.

[0091] The optical device of this embodiment is configured to further include a control unit (control means). This control unit determines a priority band signal as a wavelength band signal for each of the plurality of first optical fibers among the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal propagating through each of the plurality of first optical fibers included in the first optical transmission line 110. At this time, the control unit determines the priority band signal based on the priorities of the plurality of first wavelength band signals.

[0092] In this case, the switching unit 1101 changes the transmission path of each priority band signal to the second optical transmission path 120 in the first switching process.

[0093] Here, the priority band signals propagating through each of the plurality of first optical fibers may be configured to occupy wavelength bands that do not overlap with each other on the frequency axis.

[0094] The control unit (control means) may also determine a low-priority band from among the second wavelength bands occupied by the plurality of second wavelength band signals. The plurality of second wavelength band signals constitute a second wavelength multiplexed optical signal propagating through each of the plurality of second optical fibers included in the second optical transmission line 120. In this case, the control unit determines a low-priority band for each of the plurality of second optical fibers based on the priorities of the plurality of second wavelength band signals. In this case, the switching unit 1101 allocates the wavelength band signals to the low-priority band in the first switching process. Note that the low-priority band includes an unused band that is not occupied by the second wavelength band signals.

[0095] Next, the optical transmission method according to this embodiment will be described.

[0096] In the optical transmission method according to this embodiment, first, at a stage upstream of a fault location in a first optical transmission line, the transmission line of a wavelength band signal propagating through the first optical transmission line is changed to a second optical transmission line that is the same route as the first optical transmission line, and then, at a stage downstream of the fault location, the transmission line of the wavelength band signal is changed from the second optical transmission line to the first optical transmission line.

[0097] In the optical transmission method according to this embodiment, the process of changing the transmission path to the second optical transmission path includes the following process. That is, among the plurality of first wavelength band signals, a priority band signal is determined as a wavelength band signal for each of the plurality of first optical fibers based on the priority of the plurality of first wavelength band signals, and the transmission path of each priority band signal is changed to the second optical transmission path. Here, the plurality of first wavelength band signals constitute a first wavelength multiplexed optical signal propagating through each of the plurality of first optical fibers included in the first optical transmission path.

[0098] In this case, the priority band signals propagating through each of the plurality of first optical fibers can be configured to occupy wavelength bands that do not overlap with each other on the frequency axis.

[0099] Furthermore, the process of changing the transmission path to the second optical transmission path may include the following process. That is, among the second wavelength bands occupied by the plurality of second wavelength band signals, a low-priority band may be determined for each of the plurality of second optical fibers based on the priorities of the plurality of second wavelength band signals, and the wavelength band signals may be allocated to the low-priority band. Here, the plurality of second wavelength band signals constitute a second wavelength multiplexed optical signal propagating through each of the plurality of second optical fibers included in the second optical transmission path. Note that the low-priority band includes an unused band that is not occupied by the second wavelength band signals.

[0100] As described above, according to the optical transmission systems 3000, 3001, optical devices, and optical transmission methods of this embodiment, even if a fault occurs in part of an optical fiber in an optical cable, fault recovery can be achieved while effectively utilizing the wavelength band without impairing stable use of the optical transmission system.

[0101] The optical transmission system, optical device, and optical transmission method described in each of the above embodiments can be used in an optical submarine cable transmission system. Here, the optical device can be an optical add / drop multiplexer (OADM) that has the function of adding (adding) and dropping (dropping) an optical signal of a specific wavelength.

[0102] The first optical device and the second optical device described in the above embodiment may be arranged in a trunk section connecting opposing landing stations (trunk stations) in an optical submarine cable transmission system. However, as shown in Figures 10A and 10B, the optical devices may be arranged in a branch section connecting a branch station. Figure 10A shows an example of an operation in which the first optical device 4110 and the second optical device 4120 extract (drop) an optical signal to the branch station side when a fault location 400 exists in the branch section. Figure 10B shows an example of an operation in which the first optical device 4110 and the second optical device 4120 add (add) an optical signal from the branch station side when a fault location 400 exists in the branch section.

[0103] Furthermore, the operations of the first optical device and the second optical device in the above embodiment may be controlled by a system monitoring device serving as an optical network management device provided in a terminal device of a landing station.

[0104] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0105] (Supplementary Note 1) An optical transmission system comprising: a first optical device, located upstream of a fault location in a first optical transmission line, that changes the transmission path of a wavelength band signal propagating through the first optical transmission line to a second optical transmission line having the same route as the first optical transmission line; and a second optical device, located downstream of the fault location, that changes the transmission path of the wavelength band signal from the second optical transmission line to the first optical transmission line.

[0106] (Appendix 2) An optical transmission system as described in Appendix 1, wherein the first optical transmission path includes a plurality of first optical fibers, and the first optical device determines a priority optical fiber among the plurality of first optical fibers based on the priorities of the plurality of first optical fibers, and changes the transmission path of the wavelength band signal propagating through the priority optical fiber to the second optical transmission path.

[0107] (Supplementary Note 3) The optical transmission system according to Supplementary Note 1, wherein the first optical device determines a priority band signal as the wavelength band signal based on the priority of the plurality of first wavelength band signals among the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal propagating through the first optical transmission path, and changes the transmission path of the priority band signal to the second optical transmission path.

[0108] (Supplementary Note 4) The optical transmission system according to Supplementary Note 1, wherein the first optical transmission path includes a plurality of first optical fibers, and the first optical device determines a priority band signal as the wavelength band signal for each of the plurality of first optical fibers based on the priority of the plurality of first wavelength band signals among a plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through each of the plurality of first optical fibers, and changes the transmission path of each of the priority band signals to the second optical transmission path.

[0109] (Supplementary Note 5) The optical transmission system according to Supplementary Note 4, wherein the priority band signals propagating through each of the plurality of first optical fibers occupy wavelength bands that do not overlap with each other on the frequency axis.

[0110] (Appendix 6) The optical transmission system according to any one of Appendices 1 to 5, wherein the second optical transmission path includes a plurality of second optical fibers, and the first optical device determines a low-priority optical fiber among the plurality of second optical fibers based on the priorities of the plurality of second optical fibers, and changes the transmission path of the wavelength band signal to the low-priority optical fiber.

[0111] (Supplementary Note 7) The optical transmission system according to any one of Supplementary Notes 1 to 6, wherein the first optical device determines a low-priority band among second wavelength bands occupied by a plurality of second wavelength band signals constituting a second wavelength multiplexed optical signal propagating through the second optical transmission path based on priorities of the plurality of second wavelength band signals, and allocates the wavelength band signals to the low-priority band.

[0112] (Supplementary Note 8) The optical transmission system according to any one of Supplementary Notes 1 to 5, wherein the second optical transmission path includes a plurality of second optical fibers, and the first optical device determines a low-priority band for each of the plurality of second optical fibers based on the priority of the second wavelength band signals among second wavelength bands occupied by the plurality of second wavelength band signals constituting the second wavelength multiplexed optical signal propagating through each of the plurality of second optical fibers, and allocates the wavelength band signals to the low-priority band.

[0113] (Supplementary Note 9) The optical transmission system according to Supplementary Note 7 or 8, wherein the low-priority band includes an unused band that is not occupied by the second wavelength band signal.

[0114] (Supplementary Note 10) An optical device comprising: switching means for performing either a first switching process or a second switching process; input connection means for connecting a first optical transmission line and a second optical transmission line of the same route as the first optical transmission line to an input side of the switching means; and output connection means for connecting the first optical transmission line and the second optical transmission line to an output side of the switching means, wherein the first switching process is a process for changing a transmission line of a wavelength band signal propagating through the first optical transmission line to the second optical transmission line at a stage preceding a fault location in the first optical transmission line; and the second switching process is a process for changing the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line at a stage following the fault location.

[0115] (Appendix 11) An optical device according to appendix 10, further comprising a control means for determining a priority optical fiber among a plurality of first optical fibers included in the first optical transmission path based on priorities of the plurality of first optical fibers, wherein the switching means changes the transmission path of the wavelength band signal propagating through the priority optical fiber to the second optical transmission path in the first switching process.

[0116] (Supplementary Note 12) An optical device according to Supplementary Note 10, further comprising a control means for determining a priority band signal as the wavelength band signal based on priorities of the plurality of first wavelength band signals among the plurality of first wavelength band signals constituting the first wavelength multiplexed optical signal propagating through the first optical transmission path, wherein the switching means changes the transmission path of the priority band signal to the second optical transmission path in the first switching process.

[0117] (Supplementary Note 13) An optical device according to Supplementary Note 10, further comprising a control means for determining a priority band signal as the wavelength band signal for each of a plurality of first optical fibers, based on priorities of the plurality of first wavelength band signals among a plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through each of a plurality of first optical fibers included in the first optical transmission path, wherein the switching means changes the transmission path of each of the priority band signals to the second optical transmission path in the first switching process.

[0118] (Supplementary Note 14) The optical device according to Supplementary Note 13, wherein the priority band signals propagating through each of the plurality of first optical fibers occupy wavelength bands that do not overlap with each other on the frequency axis.

[0119] (Appendix 15) An optical device according to any one of Appendices 10 to 14, further comprising a control means for determining a low-priority optical fiber among a plurality of second optical fibers included in the second optical transmission path based on the priorities of the plurality of second optical fibers, wherein the switching means changes the transmission path of the wavelength band signal to the low-priority optical fiber in the first switching process.

[0120] (Supplementary Note 16) The optical device according to any one of Supplementary Notes 10 to 15, further comprising a control means for determining a low-priority band among second wavelength bands occupied by a plurality of second wavelength band signals constituting a second wavelength multiplexed optical signal propagating through the second optical transmission path, based on priorities of the plurality of second wavelength band signals, wherein the switching means allocates the wavelength band signals to the low-priority band in the first switching process.

[0121] (Supplementary Note 17) The optical device according to any one of Supplementary Notes 10 to 14, further comprising: a control means for determining a low-priority band for each of the plurality of second optical fibers based on priorities of the second wavelength band signals among second wavelength bands occupied by the second wavelength band signals constituting the second wavelength multiplexed optical signal propagating through each of the plurality of second optical fibers included in the second optical transmission path; and the switching means for allocating the wavelength band signals to the low-priority band in the first switching process.

[0122] (Supplementary Note 18) The optical device according to Supplementary Note 16 or 17, wherein the low-priority band includes an unused band that is not occupied by the second wavelength band signal.

[0123] (Supplementary Note 19) An optical network management device comprising: a monitoring means for monitoring occurrence of a fault in a first optical transmission line, and generating fault occurrence information when the occurrence of the fault is detected; and a control means for instructing a first optical device located upstream of a location where the fault has occurred to change the transmission line of a wavelength band signal propagating through the first optical transmission line to a second optical transmission line having the same route as the first optical transmission line, based on the fault occurrence information, and for instructing a second optical device located downstream of the location where the fault has occurred to change the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line.

[0124] (Supplementary Note 20) An optical transmission method in which, at a stage preceding a fault location in a first optical transmission line, a transmission line of a wavelength band signal propagating through the first optical transmission line is changed to a second optical transmission line having the same route as the first optical transmission line, and, at a stage following the fault location, the transmission line of the wavelength band signal is changed from the second optical transmission line to the first optical transmission line.

[0125] (Supplementary Note 21) The optical transmission method according to Supplementary Note 20, wherein changing the transmission path to the second optical transmission path includes determining a priority optical fiber among a plurality of first optical fibers included in the first optical transmission path based on priorities of the plurality of first optical fibers, and changing the transmission path of the wavelength band signal propagating through the priority optical fiber to the second optical transmission path.

[0126] (Supplementary Note 22) The optical transmission method according to Supplementary Note 20, wherein changing the transmission path to the second optical transmission path includes determining a priority band signal as the wavelength band signal based on priorities of the plurality of first wavelength band signals among the plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through the first optical transmission path, and changing the transmission path of the priority band signal to the second optical transmission path.

[0127] (Supplementary Note 23) The optical transmission method according to Supplementary Note 20, wherein changing the transmission path to the second optical transmission path includes determining a priority band signal as the wavelength band signal for each of a plurality of first optical fibers based on priorities of the plurality of first wavelength band signals among a plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through each of a plurality of first optical fibers included in the first optical transmission path, and changing the transmission path of each of the priority band signals to the second optical transmission path.

[0128] (Supplementary Note 24) The optical transmission method according to Supplementary Note 23, wherein the priority band signals propagating through each of the plurality of first optical fibers occupy wavelength bands that do not overlap with each other on the frequency axis.

[0129] (Appendix 25) The optical transmission method according to any one of Appendices 20 to 24, wherein changing the transmission path to the second optical transmission path includes determining a low-priority optical fiber among a plurality of second optical fibers included in the second optical transmission path based on the priorities of the plurality of second optical fibers, and changing the transmission path of the wavelength band signal to the low-priority optical fiber.

[0130] (Supplementary Note 26) The optical transmission method according to any one of Supplementary Notes 20 to 25, wherein changing the transmission path to the second optical transmission path includes determining a low-priority band from among second wavelength bands occupied by a plurality of second wavelength band signals constituting a second wavelength multiplexed optical signal propagating through the second optical transmission path, based on priorities of the plurality of second wavelength band signals, and arranging the wavelength band signals in the low-priority band.

[0131] (Supplementary Note 27) The optical transmission method according to any one of Supplementary Notes 20 to 24, wherein changing the transmission path to the second optical transmission path includes determining a low-priority band for each of the second optical fibers based on priorities of the second wavelength band signals among second wavelength bands occupied by the second wavelength band signals constituting a second wavelength multiplexed optical signal propagating through each of the second optical fibers included in the second optical transmission path, and arranging the wavelength band signals in the low-priority band.

[0132] (Supplementary Note 28) The optical transmission method according to Supplementary Note 26 or 27, wherein the low-priority band includes an unused band that is not occupied by the second wavelength band signal.

[0133] (Supplementary Note 29) An optical transmission method in which a first wavelength-multiplexed optical signal is propagated through a first optical transmission line, a second wavelength-multiplexed optical signal is propagated through a second optical transmission line that is the same route as the first optical transmission line, and when a fault occurs in the first optical transmission line, propagation of the second wavelength-multiplexed optical signal is stopped upstream of the location where the fault occurred, and the transmission line of wavelength band signals constituting the first wavelength-multiplexed optical signal is changed to the second optical transmission line, and the transmission line of the wavelength band signals is changed from the second optical transmission line to the first optical transmission line downstream of the location where the fault occurred.

[0134] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0135] This application claims priority based on Japanese Patent Application No. 2020-041096, filed on March 10, 2020, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0136] 1000, 2000, 2001, 3000, 3001 Optical Transmission Systems 1100 Optical equipment 1101 Switching unit 1102 Input connection 1103 Output connection 1110, 2110, 3111, 3112, 4110 First optical device 1120, 2120, 3120, 4120 Second optical device 1200 Optical Network Management Device 1210 Monitoring Department 1220 Control Unit 100, 101, 102, 400 Fault location 110 First optical transmission path 111, 112 First optical fiber 120 Second optical transmission path 121, 122 Second optical fiber

Claims

1. a first optical device that changes a transmission path of a wavelength band signal propagating through a first optical transmission path to a second optical transmission path having the same route as the first optical transmission path, at a stage preceding a fault location in the first optical transmission path; a second optical device that changes a transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path at a downstream side of the fault location, The first optical transmission path and the second optical transmission path are constituted by an operational optical fiber. Optical transmission system.

2. the first optical transmission line includes a plurality of first optical fibers that are operational optical fibers; The first optical device determines a priority optical fiber among the plurality of first optical fibers based on the priorities of the plurality of first optical fibers, and changes the transmission path of the wavelength band signal propagating through the priority optical fiber to the second optical transmission path.

2. An optical transmission system according to claim 1.

3. The first optical device determines a priority band signal as the wavelength band signal based on priorities of the first wavelength band signals among a plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through the first optical transmission path, and changes the transmission path of the priority band signal to the second optical transmission path.

2. An optical transmission system according to claim 1.

4. the first optical transmission line includes a plurality of first optical fibers that are operational optical fibers; The first optical device determines a priority band signal as the wavelength band signal for each of the plurality of first optical fibers based on the priority of the plurality of first wavelength band signals among the plurality of first wavelength band signals constituting a first wavelength multiplexed optical signal propagating through each of the plurality of first optical fibers, and changes the transmission path of each of the priority band signals to the second optical transmission path.

2. An optical transmission system according to claim 1.

5. The priority band signals propagating through each of the plurality of first optical fibers occupy wavelength bands that do not overlap with each other on a frequency axis.

5. An optical transmission system according to claim 4.

6. the second optical transmission line includes a plurality of second optical fibers that are operational optical fibers; The first optical device determines a low-priority optical fiber among the plurality of second optical fibers based on the priorities of the plurality of second optical fibers, and changes the transmission path of the wavelength band signal to the low-priority optical fiber.

6. An optical transmission system according to claim 1.

7. The first optical device determines a low-priority band among second wavelength bands occupied by a plurality of second wavelength band signals constituting a second wavelength multiplexed optical signal propagating through the second optical transmission line, based on priorities of the plurality of second wavelength band signals, and allocates the wavelength band signals to the low-priority band.

7. An optical transmission system according to claim 1.

8. A switching means for performing either a first switching process or a second switching process; an input connection means for connecting a first optical transmission line and a second optical transmission line having the same path as the first optical transmission line to an input side of the switching means; an output connection means for connecting each of the first optical transmission line and the second optical transmission line to an output side of the switching means; the first switching process is a process of changing a transmission path of a wavelength band signal propagating through the first optical transmission path to the second optical transmission path at a stage preceding a fault location in the first optical transmission path, the second switching process is a process of changing a transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path at a downstream side of the fault location, The first optical transmission path and the second optical transmission path are constituted by an operational optical fiber. light device.

9. a monitoring means for monitoring occurrence of a fault in the first optical transmission line and generating fault occurrence information when the occurrence of the fault is detected; Based on the failure occurrence information, instructing a first optical device located upstream of a location where the fault has occurred to change a transmission path of a wavelength band signal propagating through the first optical transmission path to a second optical transmission path having the same route as the first optical transmission path; Instructing a second optical device located downstream of the location where the fault has occurred to change the transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path. A control means; The first optical transmission path and the second optical transmission path are constituted by an operational optical fiber. Optical network management device.

10. changing a transmission path of a wavelength band signal propagating through a first optical transmission path to a second optical transmission path having the same route as the first optical transmission path, at a stage preceding a fault location in the first optical transmission path; changing a transmission path of the wavelength band signal from the second optical transmission path to the first optical transmission path at a downstream side of the fault location; The first optical transmission path and the second optical transmission path are constituted by an operational optical fiber. Optical transmission method.

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