阅读说明：本技术 汇接设备和海底线缆系统 (Junction device and subsea cable system ) 是由 泷川欣也 于 2020-06-04 设计创作，主要内容包括：本发明提供了一种能够在分支站侧的馈电线路中发生涉及接地故障的问题时抢救分支线路的汇接设备及海底线缆系统。该汇接设备被插入到连接第一和第二干线站和分支站的馈电线路和传输线路中,并且包括用于当电流检测装置检测到不再有电流流过汇接单元和分支站之间的馈电线时,以及当第一光信号检测装置检测到连接汇接单元和分支站的传输线路上的光信号时控制开关以连接在分支站与第一或第二干线站之间的传输线路的切换装置。(The invention provides a junction device and a submarine cable system which can rescue a branch line when a problem related to a ground fault occurs in a feeder line on the branch station side. The junction device is inserted into a feeder line and a transmission line connecting the first and second trunk stations and the branch station, and includes a switching means for controlling a switch to connect the transmission line between the branch station and the first or second trunk station when the current detection means detects that no more current flows through the feeder line between the junction unit and the branch station, and when the first optical signal detection means detects an optical signal on the transmission line connecting the junction unit and the branch station.)

1. A branch apparatus inserted into a transmission path and a power supply path connecting a first trunk station and a second trunk station, comprising:

a branching unit that is connected to a branching station through a transmission path and a power supply path, and switches a route by controlling switches inserted into the transmission path and the power supply path; and

a reconfigurable optical add-drop multiplexer (ROADM) device that is inserted into a transmission path and a power supply path connecting the branching station and the branching unit and supplies a control signal for controlling the switch of the branching unit to the branching unit, wherein

The branch device further comprises

Current detection means for detecting that no current flows through a power supply path between the branch station and the branch unit,

a first optical signal detection device for detecting an optical signal in a transmission path connecting the branching station and the branching unit, an

A switching device that controls the switch so as to connect the transmission path between the branch station and any one of the first trunk station and the second trunk station and the branch station when the current detection device detects that no current flows through the power supply path between the branch station and the branch unit, and the first optical signal detection device detects an optical signal in the transmission path connecting the branch station and the branch unit.

2. The branch device according to claim 1, wherein

The first optical signal detection device includes: a first optical signal detection unit that detects an optical signal in a transmission path directed from the branch station to the first trunk station; and a second optical signal detection unit that detects an optical signal in a transmission path directed from the branch station to the second trunk station.

3. The branch apparatus according to claim 1 or 2, further comprising

A second optical signal detection means for detecting an optical signal in a transmission path connecting said first trunk station and a second said trunk station, wherein

The second optical signal detection device includes: a third optical signal detection unit that detects an optical signal in a transmission path directed from the first trunk station to the second trunk station; and a fourth optical signal detection unit that detects an optical signal in a transmission path directed from the second trunk station to the first trunk station.

4. A branching device as claimed in claim 2 or 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the first optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the first trunk station, the switching means controls the switch so that the transmission path between the first trunk station and the branch station is connected.

5. The branch apparatus according to claim 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, the first optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the first trunk station, and the fourth optical signal detection unit of the second optical signal detection means does not detect an optical signal in the transmission path directed from the second trunk station to the first trunk station, the switching means controls the switch so that the transmission path between the first trunk station and the branch station is connected.

6. A branching device as claimed in claim 2 or 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the second optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the second trunk station, the switching means controls the switch so that the transmission path between the second trunk station and the branch station is connected.

7. The branch apparatus according to claim 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, the second optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the second trunk station, and the third optical signal detection unit of the second optical signal detection means does not detect an optical signal in the transmission path directed from the first trunk station to the second trunk station, the switching means controls the switch so that the transmission path between the second trunk station and the branch station is connected.

8. The branch apparatus according to any one of claims 1 to 7, wherein

The current detection means and the first optical signal detection means are integrated.

9. A subsea cable system comprising:

said first and second trunk stations installed on land;

a subsea cable connecting the first trunk station and the second trunk station;

the branch device according to any one of claims 1 to 8, which is inserted halfway of the submarine cable; and

a branching station connected to the branching device and installed on land.

10. A control method of a branch device inserted into a transmission path and a power supply path connecting a branch station with a plurality of trunk stations, the control method comprising:

detecting that no current flows through a power supply path between the branch station and the branch device;

detecting an optical signal in a transmission path connecting the branching station and the branching device; and the number of the first and second groups,

when a current flowing through a power supply path between the branch station and the branch device is detected, and an optical signal in a transmission path connecting the branch station and the branch device is detected,

an optical switch on a route of the transmission path is switched so that the transmission path between one of the plurality of trunk stations and the branch station is connected.

11. The control method of a branch device according to claim 10, further comprising:

when it is detected that no current flows through the power supply path between the branch station and the branch device, and an optical signal in the transmission path directed from the branch station to the first trunk station is detected,

controlling an optical switch on a route of the transmission path so that the transmission path between the first trunk station and the branch station is connected.

12. The control method of a branch device according to claim 10, further comprising:

when it is detected that no current flows through the power supply path between the branch station and the branch device, an optical signal in the transmission path directed from the branch station to the first trunk station is detected, and an optical signal in the transmission path directed from the second trunk station to the first trunk station is not detected,

controlling an optical switch on a route of the transmission path so that the transmission path between the first trunk station and the branch station is connected.

13. The control method of a branch device according to claim 10, further comprising:

when it is detected that no current flows through the power supply path between the branch station and the branch device, and an optical signal on the transmission path directed from the branch station to the second trunk station is detected,

controlling an optical switch on a route of the transmission path so that the transmission path between the second trunk station and the branch station is connected.

14. The control method of a branch device according to claim 10, further comprising:

when a current flowing through a power supply path between the branch station and the branch device is detected, an optical signal in a transmission path directed from the branch station to the second trunk station is detected, and an optical signal in a transmission path directed from the first trunk station to the second trunk station is not detected,

controlling an optical switch on a route of the transmission path so that the transmission path between the second trunk station and the branch station is connected.

Technical Field

The present invention relates to a branching device and a submarine cable system, and particularly to control of a branching device inserted into a transmission path and a power supply path connecting a plurality of trunk stations and branch stations.

Background

An undersea optical fiber cable system includes a terminal station a, a terminal station B, and a terminal station C disposed on land. The terminal station a and the terminal station B disposed to face each other are connected by an undersea optical cable. End station a and end station B are end stations terminating an undersea optical fiber cable. The terminal station a and the terminal station B are called trunk stations. An undersea optical branching device (BU) is inserted midway in the undersea optical cable between the terminal station a and the terminal station B. A subsea optical branching device (BU) is placed on the seabed. The terminal station C is called a branch station.

In the submarine optical cable system, a configuration of connecting a submarine optical branch device (BU) and a reconfigurable optical add-drop multiplexer (ROADM) device is often adopted as a device for branching a part of wavelength-multiplexed optical signals on the side of a branch station. Since the submarine optical branch device (BU) and the ROADM device cannot be integrally configured due to the limitation of the size of the submarine device enclosure, a configuration in which ROADM devices connected to the vicinity of the submarine optical branch device (BU) via submarine cables are arranged may be adopted. ROADM devices can dynamically change the path routes of a network. As an optical device for implementing a ROADM device, a Wavelength Selective Switch (WSS) is known. As ROADM devices, parts of the wavelength multiplexed optical signal are dropped by the wavelength selective switch and a new optical signal to be transmitted to the opposite station is added.

Patent document 1(PTL1) relates to an optical network system including a branch device, and proposes control of switching a power supply path in accordance with a control signal received from an end station device. Patent document 2(PTL2) relates to a submarine cable system including a branch device, and proposes a submarine cable system capable of continuing existing functions to the maximum extent by using facilities in which no fault occurs even when a fault occurs in a submarine cable or the like.

[ list of references ]

[ patent document ]

[ PTL1] International publication No. WO2013/094266

[ PTL2] International publication No. WO2016/181642

Disclosure of Invention

[ problem ] to

Fig. 8 is a block diagram for describing a configuration of a branch device used in the background art submarine cable system. The branch apparatus used in the background art submarine cable system includes: a Branching Unit (BU) composed of an optical switch circuit; and a ROADM unit having a ROADM function such as a WSS. A Branching Unit (BU) of a branching device includes a part of an optical path configuration and a part of a circuit configuration, and a ROADM unit of the branching device also includes a part of the optical path configuration and a part of the circuit configuration. For convenience of description, the optical path configuration portion and the circuit configuration portion in the Branching Unit (BU) of the branching apparatus are referred to as a branching unit 101-1(BU 101-1) and a branching unit 101-2(BU101-2), respectively. For convenience of description, the optical path configuration section and the circuit configuration section in the ROADM unit of the branching device are referred to as a ROADM unit 105-1 and a ROADM unit 105-2, respectively.

The branching unit 101-1(BU 101-1) includes optical switches 102a to 102d (optical SWs 102a to 102d) that are inserted into optical fibers connecting terminal stations and are configured to change connection routes between the terminal stations by control signals. The branching unit 101-2(BU101-2) includes an optical switch circuit 103 (optical SW circuit 103) for detecting a current in a power supply path between the ROADM unit 105-2 and the seabed.

In the normal state of the branching device in fig. 8, the ROADM unit 105-2 is connected to the branch station side of the branch unit 101-2(BU101-2) and is operated by power supply from the branch station side of the branch unit 101-2(BU 101-2). The optical switch circuit 103 (optical SW circuit 103) is provided on the branch station side of the branch unit 101-2(BU101-2), and has a control function of the optical switches 102a to 102d (optical SWs 102a to 102d) of the branch unit 101-1(BU 101-1) and a detection function of power supply in the power supply path of the branch unit 101-2(BU 101-2).

Here, when power from the branch station side is applied to the branch unit of the branch apparatus in fig. 8, the optical switches 102a to 102d (optical SWs 102a to 102d)) of the branch unit 101-1(BU 101-1) become switchable by command signals from terminal stations on land.

In normal operation, as shown in fig. 8, the optical switches 102a to 102d (optical SWs 102a to 102d) in the branching unit 101-1(BU 101-1) are connected to contacts on the branch station side, and optical signals on the trunk station side are added or dropped with respect to the branch station side.

The case where a ground fault has occurred in the branching device of fig. 8 is described with reference to fig. 9. Fig. 9 illustrates a case where a ground fault has occurred in the power supply path on the branch station side of the branch device in fig. 8. In particular, fig. 9 illustrates a case where a ground fault has occurred in the supply path between the branch station of the branch device and the ROADM unit in the branch device in fig. 8. Here, it is assumed that a ground fault has occurred in the supply path between the branch station of the branching device and the ROADM unit, but the optical fiber is not disconnected.

In the case where a ground fault has occurred in the power supply path between the branch station of the branch device and the ROADM unit 105-2, the power from the branch station does not reach the ROADM unit 105-2, and the branch device becomes a state in which power is not applied to the ROADM unit 105-2. Therefore, the branching apparatus becomes a state in which power is not applied to the branch station side of the branching unit 101-2(BU101-2) as well.

In this state, the ROADM unit 105-2 becomes inoperable due to no power supply, and it is assumed that all the trunk stations and the branch stations are disconnected in a state where the optical switches 102a to 102d (optical SWs 102a to 102d) of the branch unit 101-1(BU 101-1) are switched to the branch station side. However, here, the optical switch circuit 103 (optical SW circuit 103) provided on the branch station side of the branch unit 101-2(BU101-2) detects that no power is supplied from the branch station, and the connection state of the optical switches 102a to 102d (optical SWs 102a to 102d) of the branch unit 101-1(BU 101-1) is initialized. By initializing the connection state of the optical switches 102a to 102d (optical SWs 102a to 102d), as shown in fig. 9, the optical switches 102a to 102d (optical SWs 102a to 102d) are switched to the trunk station side. In this way, even when a ground fault occurs on the branch station side of the branch apparatus, the branch apparatus can be configured so that the optical signal of the trunk station does not experience a disconnection.

Next, occurrence of another ground fault is described in association with the problem to be solved by the present invention.

Fig. 10 illustrates a case where a ground fault occurs in a power supply path on the branch station side of the branch device of fig. 8. Here, unlike fig. 9, fig. 10 illustrates a case where a ground fault has occurred in the power supply path between the branching unit 101-2(BU101-2) and the ROADM unit 105-2. When a ground fault has occurred in the power supply path between the branch unit 101-2(BU101-2) and the ROADM unit 105-2 as in this case, the power supply from the branch station to the ROADM unit 105-2 is maintained, and the power from the branch station is applied to the ROADM unit 105-2. Thus, ROADM unit 105-2 is operational and the branch lines of the branch station are not disconnected.

However, the optical switch circuit 103 (optical SW circuit 103) provided on the branch station side of the branch unit 101-2(BU101-2) detects that there is no power supply from the branch station, and initializes the connection state of the optical switches 102a to 102d (optical SWs 102a to 102d) of the branch unit 101-1(BU 101-1). In this way, the optical switch circuit 103 (optical SW circuit 103) detects that there is no power supply from the branch station, and as shown in fig. 10, the optical switch circuit 103 (optical SW circuit 103) is automatically switched to the main station side.

The optical switch circuit 103 (optical SW circuit 103) is provided on the branch station side of the branch unit 101-2(BU101-2), and thus detects that there is no power supply from the branch station side. Therefore, it is not possible to switch to the branch station side by controlling the optical switch circuit 103 (optical SW circuit 103) until the power supply of the branch station side of the branch unit 101-2(BU101-2) is restored. Therefore, in the case where a ground fault occurs in the power supply path between the branching unit 101-2(BU101-2) and the ROADM unit 105-2, as shown in fig. 10, there is a problem in that: it is impossible to rescue the branch line until the power supply on the branch station side of the branch unit 101-2(BU101-2) is restored.

There is a voltage difference equal to or greater than several thousand voltages between the trunk station power supply path and the power supply path of the branch station in the branching device (BU), and it is technically difficult to provide a detection circuit for branch power supply exemplified by the optical switch circuit 103 (optical SW circuit 103) in fig. 8 to 10 in the power supply path on the trunk station side.

An object of the present invention is to provide a branch device and a submarine cable system capable of rescuing a branch line when a ground fault occurs in a power supply path on the branch station side.

[ problem solution ]

To achieve the above object, a branching device according to the present invention is a branching device inserted into a transmission path and a power supply path connecting a first trunk station and a second trunk station, the branching device comprising:

a branching unit that is connected to the branching station through the transmission path and the power supply path, and switches the route by controlling switches inserted into the transmission path and the power supply path; and

a reconfigurable optical add-drop multiplexer (ROADM) device that is inserted into a transmission path and a power supply path connecting a branch station and a branch unit and supplies a control signal for controlling a switch of the branch unit to the branch unit, wherein

The branch device further comprises

Current detection means for detecting that no current flows through a power supply path between the branch station and the branch unit,

a first optical signal detection device for detecting an optical signal in a transmission path connecting the branch station and the branch unit, an

Switching means for controlling the switch so as to connect the transmission path between any one of the first trunk station and the second trunk station and the branch station when the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the first optical signal detection means detects an optical signal in the transmission path connecting the branch station and the branch unit.

A submarine cable system according to the present invention comprises:

a first and second trunk station installed on land;

a subsea cable connecting the first trunk station and the second trunk station;

a branching device inserted midway in the submarine cable; and

and the branch station is connected with the branch equipment and is installed on the land.

A control method of a branch apparatus according to the present invention is a control method of a branch apparatus inserted into a transmission path and a power supply path connecting a plurality of trunk stations and branch stations, the control method including:

detecting that no current flows through a power supply path between the branch station and the branch device;

detecting an optical signal in a transmission path connecting the branch station and the branch device; and the number of the first and second groups,

when a current flowing through a power supply path between the branch station and the branch device is detected, and an optical signal in a transmission path connecting the branch station and the branch device is detected,

the optical switch is switched on the way of the transmission path so as to connect the transmission path between one of the plurality of trunk stations and the branch station.

[ advantageous effects of the invention ]

The invention provides a branch device and a submarine cable system, which can rescue a branch line when a ground fault occurs in a power supply path on the branch station side.

Drawings

Fig. 1 is a configuration diagram for describing an ocean bottom cable system according to a first exemplary embodiment of the present invention.

Fig. 2 is a configuration diagram for describing a branching device according to a first exemplary embodiment of the present invention.

Fig. 3 is a configuration diagram for describing a submarine cable system according to a second exemplary embodiment of the present invention.

Fig. 4 is a configuration diagram for describing a switching operation of the submarine cable system in fig. 3.

Fig. 5 is a configuration diagram for describing a configuration of an optical switch in a branching device according to a second exemplary embodiment of the present invention.

Fig. 6 is a configuration diagram for describing the configuration of a branching device according to the second exemplary embodiment of the present invention.

Fig. 7 is a block diagram for describing a switching operation of the branching device according to the second exemplary embodiment of the present invention when a ground fault occurs.

Fig. 8 is a block diagram for describing a configuration of a branch device used in the background art submarine cable system.

Fig. 9 is a block diagram for describing a switching operation of the branching device in fig. 8 when a ground fault occurs.

Fig. 10 is a block diagram for describing a problem involved in the branch device in fig. 8 when a ground fault occurs.

Detailed Description

Preferred exemplary embodiments according to the present invention are described in detail with reference to the accompanying drawings. In the branching device and the submarine cable system according to the preferred exemplary embodiments of the present invention, it becomes possible to detect both the power supply from the branch station and the optical signal from the branch station, and to switch the optical switch of the branching device to an appropriate state according to the conditions. It also becomes possible to realize a branching device and an undersea cable system capable of controlling an optical switch only by power supply from a branching station or only by power supply from a trunk station.

[ first example embodiment ]

A branching apparatus and an undersea cable system according to a first exemplary embodiment of the present invention are described. Fig. 1 is a configuration diagram for describing a submarine cable system according to a first exemplary embodiment of the present invention. The submarine cable system in fig. 1 includes an end station a (50A) as one example of a first trunk station installed on land, an end station B (50B) as one example of a second trunk station, and a submarine cable connecting the end station a (50A) and the end station B (50B). The submarine cable system in fig. 1 further includes a branching device inserted midway of the submarine cable, and an end station C (50C) as one example of a branching station connected to the branching device and installed on land. The submarine cable includes transmission paths 84 to 86 composed of optical fibers and power supply paths 81 to 83. The power supply path 81 is disposed along the transmission path 84, the power supply path 82 is disposed along the transmission path 85, and the power supply path 83 is disposed along the transmission path 86.

The branching apparatus of the subsea cable system of fig. 1 comprises: a branching unit 51(BU51) as a device for separating a part of the wavelength-multiplexed optical signal on the side of the terminal station C (50C); and a reconfigurable optical add/drop multiplexer (ROADM) unit 52. The branching unit 51(BU51) is a branching unit connected to a terminal station C (50C) as a branching station through a transmission path 86 and a power supply path 83. The branching unit 51(BU51) is constituted by an optical switch circuit, and switches routes by controlling switches inserted in a transmission path and a power supply path to reach the terminal station a or the terminal station B. ROADM unit 52 has ROADM functions such as WSS. The ROADM unit 52 is inserted into a transmission path 86 and a power supply path 83 connecting a terminal station C (50C) as a branch station and the branch unit 51(BU51), and supplies a control signal for controlling the switching of the branch unit 51(BU51) to the branch unit 51(BU 51).

Fig. 2 is a configuration diagram for describing a branching device according to a first exemplary embodiment of the present invention. Specifically, the branching apparatus of fig. 2 is provided in branching unit 51(BU51) of fig. 1. The branching device of fig. 2 includes a current detection means 55, an optical signal detection means 56₁Optical signal detection device 56₂And a switching device 57.

The current detection means 55 monitors the current flowing through the power supply path 83 between the terminal station C (50C) as the branch station and the branch unit 51(BU51), and detects that no current flows through the power supply path 83. The current detection means 55 detects that no current flows through the power supply path 83 by monitoring, in particular, the current in the power supply path between the ROADM unit 52 and the sea ground in the power supply path 83 between the terminal station C (50C) and the branching unit 51(BU 51). Optical signal detection device 56₁An optical signal in a transmission path 86 connecting a terminal station C (50C) as a branch station and a branch unit 51(BU51) is detected. Optical signal detection device 56₂An optical signal in a transmission path 84 or a transmission path 85 connecting a terminal station a (50A) as one example of a first trunk station and a terminal station B (50B) as one example of a second trunk station is detected.

When the current detecting means 55 detects that no current flows through the power supply path 83 between the terminal station C (50C) and the branching unit 51(BU51), and the optical signal detecting means 56₁Detecting a connected terminal station C (50C) and a branchWhen an optical signal is present in transmission path 86 of unit 51(BU51), switching device 57 controls switching of branching unit 51(BU51) so that a transmission path between any one of terminal station a (50A) and terminal station B (50B) and terminal station C (50C) is connected. In particular, the optical signal detection device 56₂Upon detecting an optical signal in transmission path 84 or transmission path 85 connecting terminal station a (50A) and terminal station B (50B), switching device 57 performs control of switching of branching unit 51(BU51), which branching unit 51(BU51) connects the transmission path between any one of terminal station a (50A) and terminal station B (50B) and terminal station C (50C).

(operation of the example embodiment)

Next, the operation of the branching device and the submarine cable system according to the first exemplary embodiment is described. For example, it is assumed that the branch device is in a normal state as shown in fig. 8 referred to in the description of the background art. In this normal state, when power from the terminal station C (50C) as a branch station is applied to the branch unit 51(BU51) of the branching apparatus of fig. 2, the branch unit 51(BU51) becomes switchable by a command signal from a terminal station on land. In normal operation, an optical signal on the trunk station side is added to or dropped from the branch station side by being connected to the branch station side within the branching unit 51(BU 51).

The branching device according to the present exemplary embodiment detects that no current flows through the power supply path 83 by monitoring the current flowing through the power supply path 83 between the terminal station C (50C) as a branching station and the branching unit 51(BU 51). The current detection device 55 detects that no current flows through the power supply path 83 by monitoring, in particular, the current in the power supply path between the ROADM unit 52 and the sea ground in the power supply path 83 between the terminal station C (50C) and the branching unit 51(BU 51). Optical signal detection device 56₁An optical signal in a transmission path 86 connecting a terminal station C (50C) as a branch station and a branch unit 51(BU51) is detected. Optical signal detection device 56₂An optical signal in a transmission path 84 or a transmission path 85 connecting a terminal station a (50A) as one example of a first trunk station and a terminal station B (50B) as one example of a second trunk station is detected. When the current detecting means 55 detects that no current flows through the terminalA power supply path 83 between the station C (50C) and the branching unit 51(BU51), and an optical signal detection device 56₁Upon detecting an optical signal in transmission path 86 connecting terminal station C (50C) and branching unit 51(BU51), switching means 57 controls switching of branching unit 51(BU51) so that the transmission path between any one of terminal station a (50A) and terminal station B (50B) and terminal station C (50C) is connected.

(advantageous effects of embodiment)

For example, when a ground fault occurs in the power supply path between ROADM unit 52 and the sea ground, current detection device 55 detects that no current flows through power supply path 83. Optical signal detection device 56₁An optical signal in the transmission path 86 connecting the terminal station C (50C) as the branch station and the branch unit 51(BU51) is detected.

Then, when the current detecting means 55 detects that no current flows through the power supply path 83 between the terminal station C (50C) and the branching unit 51(BU51), and the optical signal detecting means 56₁Upon detecting an optical signal in transmission path 86 connecting terminal station C (50C) and branching unit 51(BU51), switching apparatus 57 controls switching of branching unit 51(BU51) so as to connect the transmission path between any one of terminal station a (50A) and terminal station B (50B) and terminal station C (50C). Therefore, even when a ground fault occurs in the power supply path between ROADM unit 52 and the sea ground, the branch device can rescue the branch line. Therefore, the branch line can be salvaged without waiting for the restoration of the power supply on the branch station side of the branch equipment.

In the branching device according to the present exemplary embodiment, even when a ground fault occurs in the power supply path between the terminal station C (50C) as the branching station and the ROADM unit 52 described in the background art with reference to fig. 9, the current detection means 55 detects that no current flows through the power supply path 83. However, in this case, since power is not supplied to the ROADM unit 52, an optical signal is not detected in the transmission path 86 connecting the terminal station C (50C) and the branching unit 51(BU 51). Therefore, similarly to the case described in the background art in fig. 9, the switch of the branch device is initialized, and the switch is switched to the trunk station side. In this way, the branching device can be configured such that the optical signal of the trunk station does not undergo disconnection even when a ground fault occurs on the branch station side of the branching device.

[ second example embodiment ]

Next, a branching device and an undersea cable system according to a second exemplary embodiment of the present invention are described. The branching apparatus and the submarine cable system according to the second exemplary embodiment have a configuration in which the branching apparatus according to the first exemplary embodiment is further specified. The same reference numerals are attached to elements similar to those in the first exemplary embodiment, and detailed description thereof is omitted. Fig. 3 is a configuration diagram for describing a configuration of the submarine cable system according to the present exemplary embodiment. Fig. 4 is a configuration diagram for describing a switching operation of the submarine cable system of fig. 3. Fig. 5 is a configuration diagram for describing the configuration of an optical switch of the branching device according to the present exemplary embodiment.

(configuration of the example embodiment)

As shown in fig. 3, the branching device according to the second exemplary embodiment includes an optical switch circuit 62 (optical SW circuit 62) as one example of current detection means for detecting that no current flows through a power supply path between the terminal station C as a branching station and the branching unit 51. The branching apparatus according to the second exemplary embodiment further includes a first optical switch circuit 61 as one example of first optical signal detection means for detecting an optical signal in a transmission path between the terminal station C as a branching station and the branching unit 51₁(first optical SW Circuit 61₁). In the branching device according to the present exemplary embodiment, the current detection means and the first optical signal detection means are integrated, and the optical switch circuit 62 (optical SW circuit 62) is incorporated in the first optical switch circuit 61₁(first optical SW Circuit 61₁) And (4) the following steps. The branch device according to the second exemplary embodiment further includes a second optical switch circuit 61₂(second optical SW Circuit 61₂) As one example of second optical signal detection means for detecting an optical signal in a transmission path 84 or a transmission path 85 connecting a terminal station a (50A) as one example of a first trunk station and a terminal station B (50B) as one example of a second trunk station. The optical coupler 63 in fig. 4 is about to be removed from the landControl command signals of optical switches transmitted by terminal station devices in a station building are branched, and the branched signals are respectively transmitted to the first optical SW circuits 61₁And a second optical SW circuit 61₂。

Fig. 3 illustrates a state in which a repeater 53A is inserted in a transmission path between a terminal station a, not illustrated, and the branch unit 51, a repeater 53B is inserted in a transmission path between a terminal station B, not illustrated, and the branch unit 51, and a repeater 53C is inserted in a transmission path between a terminal station C, not illustrated, and the branch unit 51. The repeater 53A, the repeater 53B, and the repeater 53C operate by power supply from a power supply path provided along the transmission path, and amplify the optical signal in the transmission path.

The optical switches 1-1 (optical SW 1-1), 1-2 (optical SW 1-2), SW 1-3 (optical SW 1-3) and 1-4 (optical SW 1-4) in fig. 5 are all 1 × 2 type optical switches switched to the trunk station side or the branch station side, and are controlled by a first optical SW circuit 61₁And (5) controlling.

The optical switch 2-1 (optical SW 2-1), the optical switch 2-2 (optical SW 2-2), the optical switch 2-3 (optical SW 2-3) and the optical switch 2-4 (optical SW 2-4) in fig. 5 are all 2 × 2 type optical switches switched to the trunk station side or the branch station side, and are controlled by the second optical SW circuit 61₂And (5) controlling.

As shown in the lower left part of fig. 5, the 1 × 2 type optical switch switches between the ON state and the OFF state, and the 2 × 2 type optical switch switches between the ON state and the OFF state. In the operation of the optical SW shown in the lower left part of fig. 5, when the 1 × 2 type optical switch and the 2 × 2 type optical switch are in the ON state, the transmission path between one trunk station and the branch station is set to the connected state, and when the 1 × 2 type optical switch and the 2 × 2 type optical switch are in the OFF state, the transmission path between one trunk station and another trunk station is set to the connected state.

When there is no power supply from the branch station side, the first optical SW circuit 61₁The light SW circuit 62 detects this state and automatically sets the light SW1-1, the light SW 1-2, the light SW 1-3 and the optical SW 1-4 to the OFF state.

First optical SW circuit 61₁Control light SW1-1, light SW 1-2, light SW 1-3 and light SW1-4. As a first optical SW circuit 61₁There are two methods, that is, a method of setting the lights SW1-1 to 1-4 to an ON state or an OFF state by a control command signal from the land station, and a method of setting the lights SW1-1 to 1-4 to an ON state or an OFF state by the first light SW circuit 61₁The light SW circuit 62 detects that the current on the branch station side is turned OFF and automatically sets the lights SW1-1 to 1-4 to the OFF state. First optical SW circuit 61₁Operated by power supply from the branch station side of the branch device.

Second optical SW circuit 61₂Control light SW2-1, light SW2-2, light SW2-3, and light SW 2-4. As a second optical SW circuit 61₂There are two methods, that is, a method of setting the lights SW2-1 to 2-4 to an ON state or an OFF state by a control command signal from the land station, and a method of detecting an optical signal ON the trunk station side and an optical signal ON the branch station side and automatically setting the lights SW2-1 to 2-4 to an ON state or an OFF state. Second optical SW circuit 61₂Operated by the mains station side supply from the branch device.

(operation of the example embodiment)

Next, the operation of the branch device according to the present exemplary embodiment is described. The upper part of fig. 5 illustrates the configuration of the transmission path of the optical signal directed from the terminal station a to the terminal station B, and the lower right part of fig. 5 illustrates the configuration of the transmission path of the optical signal directed from the terminal station B to the terminal station a. For convenience, a direction pointing from the terminal station a to the terminal station B in fig. 5 may be referred to as "downlink", and a direction pointing from the terminal station B to the terminal station a may be referred to as "uplink". The configuration of the downlink transmission path in fig. 5 is substantially the same as the configuration of the uplink transmission path in fig. 5.

Control and operation of the downlink transmission path in fig. 5 are described. In the downstream transmission path in FIG. 5, the optical SW1-1 and the optical SW 1-2 are controlled by the first optical SW circuit 61 in FIG. 3₁And the light SW2-1 and the light SW2-2 are controlled by the second light SW circuit 61 of FIG. 3₂And (5) controlling. When there is an optical signal from the branch station side, the first optical SW circuit 61₁The optical signal is detected. The second optical SW circuit 61 when there is an optical signal from the trunk station side₂The optical signal is detected.

Description of the inventionControl and operation of the uplink transmission path in fig. 5. In the upstream transmission path of FIG. 5, the optical SW 1-3 and the optical SW 1-3 are controlled by the first optical SW circuit 61 of FIG. 3₁Control, light SW2-3 and light SW2-3 by the second light SW circuitry 61 of FIG. 3₂And (5) controlling. When there is an optical signal from the branch station side, the first optical SW circuit 61₁The optical signal is detected. The second optical SW circuit 61 when there is an optical signal from the trunk station side₂The optical signal is detected.

Fig. 4 is a configuration diagram for describing a switching operation of the submarine cable system of fig. 3. In particular, fig. 4 shows a block diagram of a power supply circuit of the branching unit 51(BU 51). First optical SW circuit 61₁Operated by power supply from the branch station side. The optical SW1-1 and the optical SW 1-2 in the downstream transmission path of fig. 5 can be set to an ON state or an OFF state, and the optical SW 1-3 and the optical SW-4 in the upstream transmission path of fig. 5 can be set to an ON state or an OFF state, by command control signals from terminal station equipment (e.g., the land station a in fig. 4) in the land station building. Here, when there is no power supply from the branch station side, the first optical SW circuit 61₁The function of detecting the branch supply current is activated and control is switched to the main station side by automatically setting the optical switches 1-1 to 1-4 to the OFF state.

The second optical SW circuit 61 is operated by supplying power from the main station side₂And by command control signals from terminal station equipment in the land station building (e.g., land station a in fig. 4), it is possible to set the optical SW2-1 and the optical SW2-2 in the downstream transmission path of fig. 5 to the ON state or the OFF state, and to set the optical SW2-3 and the optical SW 2-4 in the upstream transmission path of fig. 5 to the ON state or the OFF state. Here, when there is no power supply from the branch station side, the first optical SW circuit 61₁The function of detecting the branch supply current is activated and control is switched to the trunk station side by automatically setting the lights SW1-1 to 1-4 to the OFF state.

The optical signal detection unit 71 has a function of detecting an optical signal input from the branch station, and particularly detects an optical signal in a transmission path directed from the terminal station C as the branch station to the terminal station a as the first trunk station. The optical signal detection unit 73 has a function of detecting an optical signal input from the branch station, and particularly detects an optical signal in a transmission path directed from the terminal station C as the branch station to the terminal station B as the second trunk station.

The optical signal detection unit 72 has a function of detecting an optical signal input from a trunk station, and particularly detects an optical signal in a transmission path directed from the terminal station a as a first trunk station to the terminal station B as a second trunk station. The optical signal detection unit 74 has a function of detecting an optical signal input from the trunk station, and particularly detects an optical signal in a transmission path from the terminal station B as the second trunk station to the terminal station a as the first trunk station.

The detection results of the optical signal detection unit 71, the optical signal detection unit 72, the optical signal detection unit 73, and the optical signal detection unit 74 are sent to the second optical SW circuit 61₂And the light SW2-1, the light SW2-2, the light SW2-3 and the light SW 2-4 are controlled to be in an ON state or an OFF state. Here, in consideration of the withstand voltage difference between the branch station and the trunk station, it is preferable that the passing optical signal is transmitted to the second optical SW circuit 61 via the optical fiber₂The detection results of the optical signal detection unit 71, the optical signal detection unit 72, the optical signal detection unit 73, and the optical signal detection unit 74 are transmitted.

As a control example of the downstream transmission path in fig. 5, when both the optical signal detection unit 71 and the optical signal detection unit 72 detect the arrival of an optical signal, the second optical SW circuit 61 is operated₂And the control is switched to the branch side by automatically setting the light SW2-1 and the light SW2-2 to the ON state. When either or both of the light signal detecting unit 71 and the light signal detecting unit 72 detects no signal, the light SW2-1 and the light SW2-2 are automatically set to the OFF state. The light SW2-1 and the light SW2-2 can also be switched to the ON side or the OFF side by a command control signal from a terminal station device in a land station building.

As a control example of the upstream transmission path in fig. 5, when both the optical signal detection unit 73 and the optical signal detection unit 74 detect the arrival of an optical signal, the second optical SW circuit 61 is operated₂And by automatically setting light SW2-3 and light SW2-3 to the ON stateControl is switched to the branch side. When either or both of the light signal detecting unit 73 and the light signal detecting unit 74 detects no signal, the light SW2-3 and the light SW 2-4 are automatically set to the OFF state. The light SW2-3 and the light SW 2-4 can also be switched to the ON side or the OFF side by a command control signal from a terminal station device in a land station building.

When the branching apparatus and the submarine cable system are normally operated, power from the trunk station side and power from the branch station side are applied to the branch unit 51(BU 51).

First optical SW circuit 61₁Operable by current supply from the branch station side. By control command signals from the land station A, the first optical SW circuit 61₁A command is received and light SW1-1, light SW 1-2, light SW 1-3 and light SW 1-4 are switched to the ON state. Thus, optical signals can be transmitted between the trunk station and the branch station.

When a ground fault occurs in the power supply path between the terminal station C (50C) as the branch station and the ROADM unit 52, as described with reference to fig. 9 of the background art, the power from the branch station does not reach the branch station side of the branch unit 51(BU51) and the ROADM unit 52. Accordingly, ROADM unit 52 becomes inoperable and the branch line is disconnected. However, the optical SW circuit 62 detects that there is no power supply from the branch station, and the first optical SW circuit 61₁Light SW1-1, light SW 1-2, light SW 1-3, light SW 1-4 are automatically switched to the OFF state. By this control, in the transmission path between the trunk stations, disconnection of the trunk line can be prevented without adding or dropping a signal to or from the substation side.

When a ground fault occurs in the power supply path between the branching unit 51(BU51) and the ROADM unit 52 of the branching device, as described with reference to fig. 10 of the background art, although power from the branching station reaches the ROADM unit 52, power from the branching station does not reach the branching unit 51(BU51) of the branching device.

Also in this case, the optical SW circuit 62 in fig. 7 detects that there is no power supply from the branch station, and the first optical SW circuit 61₁Automatically apply light SW1-1 and light SW1-2, light SW 1-3 and light SW 1-4 switch to the OFF state. In this state, since electric power does not reach the branch station side, even when a control command signal from the land station a is sent to the first optical SW circuit 61₁The optical switch of branching unit 51(BU51) cannot be controlled at this time. However, in the exemplary embodiments according to the present invention including the present exemplary embodiment, the restoration of the branch signal can be achieved.

When a ground fault occurs in the power supply path between the branching unit 51(BU51) and the ROADM unit 52 of the branching device, power from the branching station reaches the ROADM unit 52, and the ROADM unit 52 is operated. Therefore, the optical signal from the branch station side is input to the branching unit 51(BU 51). The optical signal from the trunk station side is also input to the branching unit 51(BU 51).

In this case, the optical signal detection units 71, 72, 73, and 74 detect optical signals from the trunk station and the branch station. As shown in fig. 6, the optical signal detection unit 71, the optical signal detection unit 72, the optical signal detection unit 73, and the optical signal detection unit 74 detect optical signals on the branch station side and the trunk station side, and the optical signals are sent to the second optical SW circuit 61₂. The optical signal detection unit 71, the optical signal detection unit 72, the optical signal detection unit 73, and the optical signal detection unit 74 convert optical signals into electrical signals by, for example, photodiodes or the like, thereby switching optical switches.

When the light signal detection unit 73 and the light signal detection unit 74 detect the light signal, the light signal detection unit 73 and the light signal detection unit 74 automatically switch the light SW2-1 and the light SW2-2 to the ON-state. When the light signal detection unit 71 and the light signal detection unit 72 detect the light signal, the light signal detection unit 71 and the light signal detection unit 72 automatically switch the light SW2-3 and the light SW2-3 to the ON state.

(advantageous effects of embodiment)

Therefore, even when a ground fault occurs in the power supply path between the branching unit 51(BU51) and the ROADM unit 52 of the branching device, it is possible to detect both the power supply from the branching station and the optical signal from the optical branching station, and switch the optical switch of the branching device to an appropriate state depending on the situation. In this way, even when a ground fault occurs in the power supply path between the branching unit 51(BU51) and the ROADM unit 52 of the branching device, recovery of the branched signal can be achieved.

In the branch device according to the present exemplary embodiment, even when power is not supplied from the branch station, the second optical SW circuit 61 can be operated only by power supply from the trunk station₂. By a second optical SW circuit 61₂Control command signals from the land station are received, and the light SW2-1, the light SW2-2, the light SW2-3, and the light SW 2-4 are turned off or on, so that it is possible to switch between a communication state only on the trunk station side and a communication state in which signals are added to or dropped from the branch station side.

In the configuration of the background art, when a ground fault occurs between a Branching Unit (BU) of a branch and a ROADM unit, it is difficult to recover the branched signal regardless of the operation of the ROADM unit. In contrast, the configuration of the above-described exemplary embodiment enables restoration of a branch line by detecting an optical signal from a branch even when power from the branch station side is not applied to the Branch Unit (BU).

Further, the optical switch of the Branch Unit (BU) can be switched to the main station side or the branch station side by a remote control command signal from the terminal station device in the land station building regardless of whether there is power supply from the branch station side. Therefore, the branch line can be salvaged without waiting for restoration of power supply on the branch station side of the branch apparatus, and switching can be made between only the communication state on the trunk station side and the communication state in which a signal is added to or dropped from the branch station side.

In the foregoing, preferred exemplary embodiments according to the present invention have been described. However, the present invention is not limited to these. Various modifications are possible within the scope of the present invention defined by the claims, and these are also included in the scope of the present invention.

All or a portion of the exemplary embodiments disclosed above may be described as, but not limited to, the following supplementary notes.

(supplementary notes 1)

A branch apparatus inserted into a transmission path and a power supply path connecting a first trunk station and a second trunk station, comprising:

a branching unit that is connected to a branching station through a transmission path and a power supply path, and switches a route by controlling switches inserted into the transmission path and the power supply path; and

a reconfigurable optical add-drop multiplexer (ROADM) device that is inserted into a transmission path and a power supply path connecting the branch station and the branch unit and supplies a control signal for controlling a switch of the branch unit to the branch unit, wherein

The branch device further comprises

Current detection means for detecting that no current flows through a power supply path between the branch station and the branch unit,

a first optical signal detection means for detecting an optical signal in a transmission path connecting the branching station and the branching unit, an

Switching means that controls the switch so as to connect the transmission path between any one of the first trunk station and the second trunk station and the branch station when the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the first optical signal detection means detects an optical signal in the transmission path connecting the branch station and the branch unit.

(supplementary notes 2)

The branch apparatus according to supplementary note 1, wherein

The first optical signal detection device includes: a first optical signal detection unit for detecting an optical signal in a transmission path from the branch station to the first trunk station; and a second optical signal detection unit for detecting an optical signal in a transmission path from the branch station to the second trunk station.

(supplementary notes 3)

The branch apparatus according to supplementary note 1 or 2, further comprising

Second optical signal detection means for detecting an optical signal in a transmission path connecting said first trunk station and a second said trunk station, wherein

The second optical signal detection device includes: a third optical signal detection unit for detecting an optical signal in a transmission path directed from the first trunk station to the second trunk station; and a fourth optical signal detection unit for detecting an optical signal directed from the second trunk station into the transmission path of the first trunk station.

(supplementary notes 4)

The branch apparatus according to supplementary note 2 or 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the first optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the first trunk station, the switching means controls the switch so as to connect the transmission path between the first trunk station and the branch station.

(supplementary notes 5)

The branch apparatus according to supplementary note 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, the first optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path from the branch station to the first trunk station, and the fourth optical signal detection unit of the second optical signal detection means does not detect an optical signal in the transmission path directed from the second trunk station to the first trunk station, the switching means controls the switch so as to connect the transmission path between the first trunk station and the branch station.

(supplementary notes 6)

The branch apparatus according to supplementary note 2 or 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, and the second optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the second trunk station, the switching means controls the switch so that the transmission path between the second trunk station and the branch station is connected.

(supplementary notes 7)

The branch apparatus according to supplementary note 3, wherein

When the current detection means detects that no current flows through the power supply path between the branch station and the branch unit, the second optical signal detection unit of the first optical signal detection means detects an optical signal in the transmission path directed from the branch station to the second trunk station, and the third optical signal detection unit of the second optical signal detection means does not detect an optical signal in the transmission path directed from the first trunk station to the second trunk station, the switching means controls the switch so as to connect the transmission path between the second trunk station and the branch station.

(supplementary notes 8)

The branch apparatus according to any one of supplementary notes 1 to 7, wherein

The current detection means and the first optical signal detection means are integrated.

(supplementary notes 9)

A subsea cable system comprising:

said first and second trunk stations installed on land;

a subsea cable connecting the first trunk station and the second trunk station;

the branching device according to any one of supplementary notes 1 to 8, which is inserted halfway in the submarine cable; and

a branch station connected with the branch device and installed on land.

(supplementary notes 10)

A control method of a branch device inserted into a transmission path and a power supply path connecting a plurality of trunk stations and branch stations, the control method comprising:

detecting that no current flows through a power supply path between the branch station and the branch device;

detecting an optical signal in a transmission path connecting the branching station and the branching device; and the number of the first and second groups,

when a current flowing through a power supply path between the branch station and the branch device is detected, and an optical signal in a transmission path connecting the branch station and the branch device is detected,

an optical switch on a route of the transmission path is switched so that the transmission path between one of the plurality of trunk stations and the branch station is connected.

(supplementary notes 11)

The branch device control method according to supplementary note 10, further comprising:

when it is detected that no current flows through the power supply path between the branch station and the branch device, and an optical signal on the transmission path from the branch station to the first trunk station is detected,

an optical switch on the route of the transmission path is controlled so that the transmission path between the first trunk station and the branch station is connected.

(supplementary notes 12)

The branch device control method according to supplementary note 10, further comprising:

when it is detected that no current flows through the supply path between the branch station and the branch device, an optical signal in the transmission path directed from the branch station to the first trunk station is detected, and an optical signal in the transmission path directed from the second trunk station to the first trunk station is not detected,

an optical switch on the route of the transmission path is controlled so that the transmission path between the first trunk station and the branch station is connected.

(supplementary notes 13)

The branch device control method according to supplementary note 10, further comprising:

when it is detected that no current flows through the power supply path between the branch station and the branch device, and an optical signal on the transmission path directed from the branch station to the second trunk station is detected,

controlling an optical switch on a route of the transmission path so that the transmission path between the second trunk station and the branch station is connected.

(supplementary notes 14)

The branch device control method according to supplementary note 10, further comprising:

when detecting a current flowing through a power supply path between the branch station and the branch device, detecting an optical signal in a transmission path directed from the branch station to the second trunk station, and not detecting an optical signal in a transmission path directed from the first trunk station to the second trunk station,

controlling an optical switch on a route of the transmission path so that the transmission path between the second trunk station and the branch station is connected.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the present invention is not limited to these exemplary embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

This application is based on and claims the benefit of priority from Japanese patent application No.2019-116239, filed 24.6.2019, the disclosure of which is incorporated herein by reference in its entirety.

[ list of reference signs ]

50A terminal station A

50B terminal station B

50C terminal station C

51 branching unit

52 ROADM unit

53A, 53B, 53C repeater

55 current detection device

56₁Optical signal detection device

56₂Optical signal detection device

57 switching device

61₁First optical switch circuit

61₂Second optical switch circuit

62 optical switch circuit

63 optical coupler

71. 72, 73, 74 optical signal detection unit

81. 82, 83 power supply path

84. 85, 86 transmission path