Abstract: A method of identifying a fault in an optical link comprises continually storing samples of a signal that represents a power of an optical signal received over the optical link. When a fault is detected on said optical link, at least one stored series of samples of the signal is retrieved. The method then comprises performing a classification on the retrieved series of samples, in order to classify the series of samples as resulting from one of a plurality of predefined faults.

Abstract: A communications network remote node having a downstream optical circuit configured to receive downstream, DS, optical signals from an active main node and from a standby main node, the downstream optical circuit switchable between a working mode and a protection mode. Optical receivers are configured to receive the demultiplexed downstream optical signals and output encapsulated downstream client signals. Optical transmitters are configured to receive encapsulated upstream client signals and to transmit upstream, US, optical signals at upstream wavelengths carrying the encapsulated upstream client signals. An upstream optical circuit is configured to multiplex the upstream optical signals carrying the encapsulated upstream client signals and to send the upstream optical signals to both main nodes.

Abstract: An indicator system (200) for optical ports (125) of a passive optical communications equipment (120). The indicator system comprises a plurality of photodetectors (510) configured to detect an optical signal on the optical ports and a plurality of (140) configured to indicate on which optical ports an optical signal is detected by the photodetector. The indicator system further comprises a power source (350) configured to provide power to the photodetectors (510) and indicators (140). The power source is self-contained at the passive optical communications equipment. The power source (350) comprises a mechanical to electrical converter (410).

Abstract: A method of identifying a fault in an optical link comprises continually storing samples of a signal that represents a power of an optical signal received over the optical link. When a fault is detected on said optical link, at least one stored series of samples of the signal is retrieved. The method then comprises performing a classification on the retrieved series of samples, in order to classify the series of samples as resulting from one of a plurality of predefined faults.

Abstract: A method of managing a node in a cluster of nodes in an SDN network. The method comprising receiving from the node a request to join the cluster and a list of references authenticating the node. The references are verified and if the referenced passed the verification the node is allowed to join the cluster. Then a trust level of the node is calculated based on the number of verified references, wherein a role of the node in the cluster depends on the trust level of said node.

Abstract: Optical protection switching apparatus (10), for a single fibre bidirectional WDM optical ring, comprising: first (12) and second (14) ports for coupling to first and second adjacent portions of a single fibre bidirectional WDM optical ring; an optical splitter (16) comprising an input to receive a WDM aggregate optical signal, and first and second outputs coupled to the first and second ports; an optical switch (108) between the second output and the second port; and processing circuitry (24) to receive at least one of an indication of transmission continuity in the optical ring and an indication of transmission discontinuity in the optical ring, and to generate a switch control signal (20) comprising instructions to cause the optical switch to be open when there is transmission continuity in the optical ring and to cause the optical switch to be closed when there is transmission discontinuity in the optical ring.

Abstract: Optical protection switching apparatus (10), for a single fibre bidirectional WDM optical ring, comprising: first (12) and second (14) ports for coupling to first and second adjacent portions of a single fibre bidirectional WDM optical ring; an optical splitter (16) comprising an input to receive a WDM aggregate optical signal, and first and second outputs coupled to the first and second ports; an optical switch (108) between the second output and the second port; and processing circuitry (24) to receive at least one of an indication of transmission continuity in the optical ring and an indication of transmission discontinuity in the optical ring, and to generate a switch control signal (20) comprising instructions to cause the optical switch to be open when there is transmission continuity in the optical ring and to cause the optical switch to be closed when there is transmission discontinuity in the optical ring.

Abstract: A method of managing a node in a cluster of nodes in an SDN network. The method comprising receiving from the node a request to join the cluster and a list of references authenticating the node. The references are verified and if the referenced passed the verification the node is allowed to join the cluster. Then a trust level of the node is calculated based on the number of verified references, wherein a role of the node in the cluster depends on the trust level of said node.

Abstract: A flexible array probe is disclosed suitable for use in the non-destructive testing and inspection of test pieces with varying cross-sectional geometries. Array elements—such as, but not limited to, eddy current sensors, piezoelectric sensor elements, and magnetic flux leakage sensors—are mounted on thin alignment fins and coupled together with pairs of pivot mechanisms along the axis of desired rotation. The pivot mechanisms allow rotation in exactly one dimension and force the flexible array probe to align its elements orthogonally to the surface of the structure under test. Alignment and coupling fixtures are also disclosed.

Abstract: A flexible array probe is disclosed suitable for use in the non-destructive testing and inspection of test pieces with varying cross-sectional geometries. Array elements—such as, but not limited to, eddy current sensors, piezoelectric sensor elements, and magnetic flux leakage sensors—are mounted on thin alignment fins and coupled together with pairs of pivot mechanisms along the axis of desired rotation. The pivot mechanisms allow rotation in exactly one dimension and force the flexible array probe to align its elements orthogonally to the surface of the structure under test. Alignment and coupling fixtures are also disclosed.