British Telecommunications Public Limited Company

Douglas L Williams

Graeme Douglas Maxwell

Jonathan R Armitage

Raman Kashyap

Benjamin J Ainslie

Stephen A Cassidy

Peter Paul Smyth

Andrew Gordon Davis

Richard Wyatt

Michael J Robertson

Timothy Sean Stevens

Michael Charles Brierley

Raymond P Smith

Roger Alyn Payne

Timothy Stevens

Howard John Wickes

Trevor Keith White

Philip Coackley

Gerard Sherlock

Robert John Campbell

A wireless access point () connected to a fixed telecommunications network () broadcasts codes relating to one or more network identities () identifying availability of wireless connection to the access point, If connection to the telecommunications network () is lost, it suspends one of the identity codes () and replaces it with a special identity code for a network identity () configured to co-operate with a mobile terminal () equipped to recognize the special identity code and transmit a message over another communications link () to alert a service center () to the fault ().

Network access fault reporting

It has been demonstrated that B containing glasses are sensitive to radiation in the band 225-275 nm and, therefore, B,O,glasses are particularly adapted to receive refractive index modulation, e.g., to make reflection gratings. Glasses containing SiO,and B,O,are particularly suitable when the grating is to be localized in the cladding of a fiber. Glasses containing SiO,, GeO,, and B,O,are suitable when the grating is in the path region of a waveguide, e.g., in the core of a fiber.

Photo induced grating in B2O3 containing glass

An optical device includes a waveguiding configuration and an electrical capacitive configuration. The capacitive configuration includes glass electrode region(s) and glass dielectric region(s) with electrical leads, e.g., metallic conductors, for applying electrical control signals to the electrode region(s). The preferred metals for the conductors are Ni, Ti and Au. The waveguiding structure is configured so that the fields associated with optical signals propagating therein interact with dielectric region(s). During the use of the device control signals are applied to the dielectric region(s) by the electrical leads. The control signals have the effect that temporary electric fields are applied to the dielectric region(s). The fields change the optical properties of the dielectric region(s) and this affects the propagation of the optical signals. The device can either be produced in planar or fibre configurations.

Optical waveguide device including an electrical capacitive configuration

Boron containing glasses are sensitive to radiation in the band 225-275 nm and therefore, B.sub.2 O.sub.3 glasses are particularly adapted to receive refractive index modulation, e.g., to make reflection gratings. Glasses containing SiO.sub.2 and B.sub.2 O.sub.3 are particularly suitable when the grating is to be localized in the cladding of a fibre. Glasses containing SiO.sub.2, GeO.sub.2 and B.sub.2 O.sub.3 are suitable when the grating is in the path region of a waveguide, e.g., in the core of a fibre.

Photoinduced grating in B.sub.2 O.sub.3 containing glass

Laser

Free space optical communication system

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Grundisburgh, United Kingdom

Douglas L Williams