British Telecommunications Corporation

British Telecommunications Public Limited Company

Ian D Henning

David W Faulkner

David Wake

Russell P Davey

Dianne M Russ

David I Fordham

Alistair Hutcheon

A communications network has a communications station, such as a telephone exchange, and at least one interface, such as a cabinet. A plurality of optical carriers are provided between the exchange and a cabinet, thereby allowing modulation of the signals, for example xDSL modulation, to be carried out at the exchange, rather than at the cabinet. This arrangement reduces the need to power the cabinet.

Broadband communications

Control of optical systems

Light is amplified in a semiconductor laser structure through which a current is passed and (a) the wavelength of the light is greater than the wavelength of maximum gain of the laser structure, or (b) injection locking is avoided, or (c) the current is controlled so as at least partly to compensate for the decrease in the monitored light output at a wavelength or over a wavelength range distinct from that of the emitted amplified signal. In this way relatively high input powers can be amplified.

Optical amplification

Growing community of inventors

Ipswich, United Kingdom

Ian D Henning