British Telecommunications Public Limited Company

Anthony J Dann

Paul John Cannard

A vertical cavity surface emitting laser includes a mirror having first and second layers with first layers containing the elements aluminum, arsenic and antimony and second layers comprising the elements gallium, phosphorus and antimony. Both of these layers are lattice matched to the semiconductor material of the active zone. A VCSEL usually contains two mirrors and, preferably, both mirrors are formed of the elements as specified above. Beryllium can be used to confer p-type conductivity on one mirror and silicon to confer n-type conductivity on the other mirror. Preferably the active zone is formed of semiconductors containing at least one of indium and gallium and at least of phosphorus and arsenic. Conveniently the active zone has a lattice constant substantially equal to that of the indium phosphide and both mirrors are lattice matched to this constant.

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Ipswich, United Kingdom

Anthony J Dann