The Post Office

Michael Robert Matthews

David R Smith

Alan G Steventon

David H Newman

A double heterostructure semiconductor laser having the configuration of its optical cavity arranged to impose a constraint on the lasing filament as the spatial distribution of the lasing filament changes from that occuring at the start of the lasing regime, so that the optical flux emitted by the laser has self-saturating properties. This protects the laser from catastrophic facet erosion and enables a simpler control circuit to be used to drive this laser when it is used as a light source for an optical communications system.

Self saturating semiconductor lasers

A dielectric optical waveguide coupler for optically coupling together two lengths of dielectric optical waveguide consists of a tube having a capillary bore, into which may be inserted, from each end of the tube, the two dielectric optical waveguides to be joined. The capillary bore is tapered at each end to facilitate the insertion of the dielectric optical waveguides. The dielectric optical waveguide coupler may be made by immersing a capillary bore tube with its capillary bore filled with water into an etchant solution.

Method of making an optical waveguide coupler

A coupler for optically connecting two lengths of dielectric optical waveguide has a plug and a socket. The socket consists of a sleeve having a first capillary bore tube rigidly fixed in the sleeve and a second capillary bore tube slidable in the sleeve. A length of dielectric optical waveguide is threaded through the first tube and partially threads the second tube. The plug consists of a capillary bore tube of similar cross-section to the second capillary bore tube, with a length of dielectric optical waveguide partially threading, and rigidly attached to the capillary bore tube. When the plug is inserted in the socket the second capillary tube slide back along the length of the dielectric optical waveguide which is thus guided into the plug capillary bore. A modification of the invention provides a plug and socket connection for simultaneously joining a large number of dielectric optical waveguides.

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London, United Kingdom

Michael Robert Matthews