Provided are a junction device and an undersea cable system capable of saving a branch line when a problem involving ground fault occurs in a power feed line on a branch station side. This junction device is inserted into a power feed line and a transmission line connecting first and second trunk stations and a branch station, and includes a switching means for controlling a switch so as to connect the transmission line between the branch station and the first or second trunk station when a current detection means detects that there is no longer current flowing through the power feed line between a junction unit and the branch station and when a first optical signal detection means detects an optical signal in the transmission line connecting the junction unit and the branch station.

Embodiments of the present disclosure include a pluggable optical line system module for amplification, multiplexing, and demultiplexing of coherent optical signals that can be integrated with a switch-router. Integration may include mechanical, electrical, and software control aspects. One example embodiment of the optical line system is in an industry standard small form factor pluggable module such as OSFP (octal small form factor pluggable) or QSFP (quad small form factor pluggable). When configured in a switch-router, the pluggable optical line is powered, managed and controlled by the switch-router which greatly reduces the cost, space, power and the management complexity of optical line systems.

Embodiments of the present disclosure include a pluggable optical line system module for amplification, multiplexing, and demultiplexing of coherent optical signals that can be integrated with a switch-router. Integration may include mechanical, electrical, and software control aspects. One example embodiment of the optical line system is in an industry standard small form factor pluggable module such as OSFP (octal small form factor pluggable) or QSFP (quad small form factor pluggable). When configured in a switch-router, the pluggable optical line is powered, managed and controlled by the switch-router which greatly reduces the cost, space, power and the management complexity of optical line systems.

A path protection method includes receiving, by a source node of a first path, a path event notify message from a first node on the first path. The path event notify message includes indication information that the first path is predicted to fail. The path protection method further includes obtaining, by the source node, information about a predicted protection path. The information about the predicted protection path includes resource information of a second path useable to protect a service on the first path. The first path and the second path include the source node and a same sink node. The path protection method further includes storing, by the source node, the resource information of the second path.

A polarization dependent loss (PDL) compensation device for an optical system can be configured to output a compensating PDL to at least partially cancel a PDL of the optical system. In certain embodiments, the device can include a first polarization controller configured to modify a state of polarization of an optical signal, a PDL emulator disposed upstream of the first polarization controller and configured to output the compensating PDL upstream of the first polarization controller, and a second polarization controller disposed upstream of the PDL emulator and configured to modify a state of polarization of the optical signal upstream of the PDL emulator.

A polarization dependent loss (PDL) compensation device for an optical system can be configured to output a compensating PDL to at least partially cancel a PDL of the optical system. In certain embodiments, the device can include a first polarization controller configured to modify a state of polarization of an optical signal, a PDL emulator disposed upstream of the first polarization controller and configured to output the compensating PDL upstream of the first polarization controller, and a second polarization controller disposed upstream of the PDL emulator and configured to modify a state of polarization of the optical signal upstream of the PDL emulator.

Techniques for determining an alternative communication mode for vehicle-to-vehicle communication at a host vehicle can include monitoring the primary mode of RF communication to ensure it is effectively communicating and, if not, intelligently selecting a backup communication mode comprising one or more other sensors and/or systems of the vehicle. The selection of the backup communication mode may take into account various factors that can affect the various modes of communication from which the backup communication mode is selected.

Techniques for determining an alternative communication mode for vehicle-to-vehicle communication at a host vehicle can include monitoring the primary mode of RF communication to ensure it is effectively communicating and, if not, intelligently selecting a backup communication mode comprising one or more other sensors and/or systems of the vehicle. The selection of the backup communication mode may take into account various factors that can affect the various modes of communication from which the backup communication mode is selected.

Techniques for determining an alternative communication mode for vehicle-to-vehicle communication at a host vehicle can include monitoring the primary mode of RF communication to ensure it is effectively communicating and, if not, intelligently selecting a backup communication mode comprising one or more other sensors and/or systems of the vehicle. The selection of the backup communication mode may take into account various factors that can affect the various modes of communication from which the backup communication mode is selected.

In order to provide a path switching apparatus capable of continuing communication by operation corresponding to the state of occurrence of a failure, this path switching apparatus is configured to be provided with a first switching device 1, a second switching device 2, a detection circuit 3, and a control circuit 4. The first switching device 1 switches, using a first switch, connection between a first submarine cable and either a predetermined optical path or a third submarine cable connected to an optical branching/insertion device. The second switching device 2 switches, using a second switch, connection between a second submarine cable and either the predetermined optical path connected to the first switch or the third submarine cable connected to the optical branching/insertion device.