Systems and methods include, responsive to a fault affecting an optical service on an active path in an optical network operating at a frequency μ1 via an optical transceiver and having optical line protection via an optical protection switch, switching to an inactive path that now becomes the active path and finding a new route in the optical network for the inactive path that has the fault; responsive to being unable to find a route at the frequency μ1, switching the inactive path to a new route at a different frequency μ2; and implementing spectrum coordination relative to the inactive path to either determine the frequency μ1 is available on the new route or to find another new route for the inactive path where the frequency μ1 is available.

A method in a physical network controller (130) for configuring physical resources to provide a physical layer connection in a communications network (100). The physical layer connection provides physical connectivity for a higher layer network connection controlled by a higher layer network controller (120) in a hierarchical arrangement with the physical network controller (130). The method comprising the physical network controller (130) receiving (210) an indication for a minimum traffic capacity for the physical layer connection. The physical network controller configuring (220) physical resources according to the received indication.

Systems and methods for managing a list or restoration paths are provided. A method, according to one implementation, includes obtaining a list of restoration paths used for restoring transmission in a network when a home path between an originating node and a termination node is unavailable. The restoration paths are listed in a specific order based on ongoing transmission costs, where the ongoing transmission cost for each restoration path is based on characteristics associated with transmitting signals along the respective restoration path. The method also includes the step of reordering the restoration paths in the list based on restoration costs and the ongoing transmission costs. The restoration cost for each restoration path is based on a procedure for switching from the home path to the respective restoration path.

An apparatus includes a first reconfigurable optical add/drop multiplexer (ROADM) to receive a first optical signal and a second ROADM to receive a second optical signal. The apparatus also includes a reconfigurable optical switch that includes a first switch, switchable between a first state and a second state, to transmit the first optical signal at the first state and block the first optical signal at the second state. The reconfigurable optical switch also includes a second switch, switchable between the first state and the second state, to transmit the second optical signal at the first state and block the second optical signal at the second state. The reconfigurable optical switch also includes an output port to transmit an output signal that is a sum of possible optical signals transmitted through the first switch and the second switch.

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.

A method and an apparatus for spectrum defragmentation, where the method includes: obtaining, by a transmit end, a target data stream; sending the target data stream on one line using a to-be-adjusted frequency band; adjusting, on another line, an occupied frequency band of the target data stream from the to-be-adjusted frequency band to a target frequency band; switching the target data stream to the other line; and transmitting the target data stream using the target frequency band.

A control device includes: a transmission configuration information storage unit configured to manage a transmission path that connects the plurality of transmission apparatuses to each other, and whether a redundant configuration in a transmission layer is available for the transmission path; a route information storage unit configured to manage a route configured between the plurality of routers and a transmission path used on the route; and a transfer path establishing unit configured to, in response to an establishment request including a requirement for the redundant configuration for a transfer path connecting the plurality of routers to each other, refer to the transmission configuration information storage unit and the route information storage unit, establish a transfer path using a redundant route when a redundant configuration in a transfer layer is required as the requirement in the redundant configuration, and establish a transfer path not using the redundant route but being linked to the transmission path with the redundant configuration in the transmission layer when the redundant configuration in the transmission layer is required as the requirement for the redundant configuration.

Described herein is an apparatus including a continuous wave idler and an optical coupler that provide an optical signal having a power greater than optical channels carrying data, and positioned at a cross-over point between two spectral bands, with each band encompassing multiple optical channels.

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.

An apparatus includes a first reconfigurable optical add/drop multiplexer (ROADM) to receive a first optical signal and a second ROADM to receive a second optical signal. The apparatus also includes a reconfigurable optical switch that includes a first switch, switchable between a first state and a second state, to transmit the first optical signal at the first state and block the first optical signal at the second state. The reconfigurable optical switch also includes a second switch, switchable between the first state and the second state, to transmit the second optical signal at the first state and block the second optical signal at the second state. The reconfigurable optical switch also includes an output port to transmit an output signal that is a sum of possible optical signals transmitted through the first switch and the second switch.