Abstract: Optical communication systems, terminal facilities of an optical communication system, optical communication methods, and methods of communicating within an optical network are provided. According to one aspect of the invention, an optical communication system includes: a plurality of optical communication conduits individually configured to communicate data communication signals; an optical switch adapted to optically couple a communication path of an associated data terminal with at least one of the optical communication conduits; and a controller configured to monitor the data communication signals and to control the optical switch responsive to the monitoring of the data communication signals.

Abstract: An method, apparatus, and computer program product for restoring a failed system in an optical mesh network. A system includes a first light termination element (LTE) and a second LTE. A first node in the network includes an optical switching unit (OSU) coupled to the first (LTE) of the system. A second node in the network includes a second OSU coupled to the second (LTE) of the system. The first node is coupled to the second node by a path. Optical data traffic can be transmitted between the first node and the second node via the path. Upon detection of a failure of the system, the first OSU and second OSU are notified of the failure. A primary role is assigned to one of the first and second OSUs, and a secondary role is assigned to the other one of the first and second OSUs. A primary restoration plan is determined by the primary OSU. Information identifying the primary restoration plan is sent from the primary OSU for effecting the restoration path to restore the system.

Abstract: A method of monitoring performance of an optical communications system measures (i) sub-carrier signal-to-noise ratio, (ii) optical signal signal-to-noise ratio, and (iii) measuring optical signal bit error rate, and diagnoses a system component failure based upon measured sub-carrier signal-to-noise ratio, optical signal signal-to-noise ratio, and optical signal bit error rate.

Abstract: An method, apparatus, and computer program product for restoring a failed system in an optical mesh network. A system includes a first light termination element (LTE) and a second LTE. A first node in the network includes an optical switching unit (OSU) coupled to the first (LTE) of the system. A second node in the network includes a second OSU coupled to the second (LTE) of the system. The first node is coupled to the second node by a path. Optical data traffic can be transmitted between the first node and the second node via the path. Upon detection of a failure of the system, the first OSU and second OSU are notified of the failure. A primary role is assigned to one of the first and second OSUs, and a secondary role is assigned to the other one of the first and second OSUs. A primary restoration plan is determined by the primary OSU. Information identifying the primary restoration plan is sent from the primary OSU for effecting the restoration path to restore the system.

Abstract: An optical telecommunications system node terminates a plurality of optical cable routes. Each of the optical cable routes includes a traffic route and a restoration route. The node includes a plurality of traffic wavelength division multiplexers and a plurality of restoration wavelength division multiplexers. A traffic wavelength division multiplexer is connected to each traffic route and a restoration wavelength division multiplexer is connected to each restoration route. The node includes a plurality of optical cross connect layers. Each optical cross connect layer includes a connection to each of the traffic wavelength division multiplexers and to each of the restoration wavelength division multiplexers.

Abstract: Optical loop-back is provided within an optical restoration system of an optical communication network. According to one embodiment, an optical restoration system includes first and second spare optical links (also called restoration paths) optically coupled in parallel between first and second optical cross-connect switches. Each restoration path includes a light regenerator and an optical amplifier. First and second optical cross-connect switches are each switched to provide respective optical loop-back paths between the first and second restoration paths or spare links. In one example, the optical loop-back paths can be configured within the optical cross-connect switches. In another example, the optical cross-connect switches are configured to couple optical signals between an external loop-back coupler and the first and second restoration paths or spare links.