Marconi Communications Gmbh

Polatis Limited

David Owen Lewis

Robert C Goodfellow

Andrew Nicholas Dames

Michael F Grant

Richard Andrew Jensen

Nicholas Parsons

Adrian Holdsworth

A network protection switching mechanism comprises a plurality of optical switches located at a plurality of nodes; a plurality of optical communication paths between said switches; switch based fault detectors located as part of at least two switches which generate detection results representative of the identification of a fault; switch based controllers located as part of said at least two switches; and internal switch-communication means between said fault detectors and said controllers which facilitate the transmission of detection results from said fault detectors to said controllers; wherein said controllers directly cause switching to an alternative optical communication path dependent upon the receipt of said detection results; whereby autonomous switch based protection without dependence on either inter-switch control communication or higher level network control communication is achieved.

Network protection switching mechanisms and methods of network protection

An optical connector () comprises at least one optical guide () for carrying optical radiations; a total internal reflection surface () upon which, in use, said radiations impinge, so that the radiation in the optical guide is reflected by said surface towards an optical element () of the connector and means enabling the connector () to interlock with any other optical connector which is appropriately matingly configured.

Optical connector with total internal reflection abutting surface

An optical communications system for communication of a plurality of wavelength multiplexed channels. The communications system comprises a node. The node comprises a plurality of add-drop multiplexers (ADM), one per channel. Each ADM comprises a tributary. The ADMs are interconnected by the tributaries.

Traffic switching between different wavelength multiplexed channels in optical communications systems

A method for upgrading an-optical communications system in which the system comprises a plurality of nodes linked by one or more optical paths. Each path for the communication of traffic includes a single optical channel. Each node comprises add/drop multiplexers (ADM) for adding and dropping signals in electrical form, and conversion circuitry for converting between electrical and optical form signals output by the ADM for transmission via a first one of the optical paths, and for converting signals received via a second one of the optical paths for input to the ADM. The method comprises the steps of installing optical demultiplexers for selecting signals received via the second one of the optical paths according to wavelength for input to the ADM; installing circuitry for converting the signals output by the ADM into a first stable narrow wavelength band optical signal; and installing optical multiplexers for guiding the first signal into the first optical path to allow one or more further stable narrow wavelength band optical signals having different wavelengths from the first signal to be added and combined with the first signal into the first optical path.

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Warwickshire, United Kingdom

David Owen Lewis