British Telecommunications Public Limited Company

Other

British Telecommunications Corporation

Ian F Lealman

Michael J Robertson

Paul C Spurdens

Simon Cole

William J Devlin

Makoto Okai

Simon D Perrin

David M Cooper

Andrew W Nelson

Adrian R Thurlow

Michael J Harlow

Roger Alyn Payne

John Vincent Collins

Joseph J Isaac

Philip John Fiddyment

William James Duncan

An optical filter is formed from at least two grating located in a waveguide region of a semiconductor optical device. Each grating has a multiple peak optical passband. The gratings are spaced apart in the waveguide region and form an optical cavity having a comb-filter characteristic. The gratings may be located in the active region of an optical gain element and in a preferred example are superstructure gratings (SSGs). A number of filters may be joined together in series.

Optical filters

A semiconductor optical device, for example a laser, has a composite optical waveguide including a tapered, MQW active waveguide in optical contact with a substantially planar, passive waveguide. The fundamental optical mode supported by the composite waveguide varies along the length of the composite waveguide so that, in a laser, the laser mode is enlarged and is a better match to single mode optical fibre. A method for making such semiconductor optical devices is also disclosed.

Method for making optical device with composite passive and tapered

Packaged optical device

A semiconductor optical device, for example a laser, has a composite optical waveguide including a tapered, MQW active waveguide in optical contact with a substantially planar, passive waveguide. The fundamental optical mode supported by the composite waveguide varies along the length of the composite waveguide so that, in a laser, the laser mode is enlarged and is a better match to single mode optical fiber. A method for making such semiconductor optical devices is also disclosed.

Optical device with composite passive and tapered active waveguide

Electrical barrier structure for semiconductor device doped with

An optical filter is formed from at least two gratings (102,103) located in a waveguide region (104) of a` semiconductor optical device (101). Each grating has a multiple peak optical passband. The gratings are spaced apart in the waveguide region and form an optical cavity having a comb-filter characteristic. The gratings may be located in the active region of an optical gain element and in a preferred example are superstructure gratings (SSGs). A number of filters may be joined together in series.

Optical comb filters used with waveguide, laser and manufacturing method

Semiconductor laser amplifiers

In a semiconductor buried heterostructure laser having a mesa (2, 3, 4) and confinement layers (5, 6, 7) on a substrate (12), at least the lowermost of the confinement layers (5, 6, 7) is substantially planar up to the mesa. This is achieved by MOVPE growth of InP against lateral surfaces of the mesa (2, 3, 4) which are defined by distinct crystallographic planes of the material of the mesa. In particular (111) B InP planes are used. The laser is particularly for use in the field of optical communications.

Method of manufacturing semiconductor structures

Growing community of inventors

Ipswich, United Kingdom

Ian F Lealman