Patent ID: 8457170

Claim:
A vertical cavity surface emitting laser diode device, comprising a substrate; a first layer stack of semiconducting layers on said substrate, said first layer stack forming a first distributed Bragg reflector; an active region comprising one or more quantum well layers on said first layer stack; a second layer stack of semiconducting layers on said active region, said second layer stack forming a second distributed Bragg reflector; first and second terminal contacts for injecting electrical current into said active region; and, layers forming a distributed phototransistor sensitive to the laser light generated by said vertical cavity surface emitting laser diode, said layers forming the distributed phototransistor which in use provides a distributed active current confinement, the distributed phototransistor comprising at least one base layer, at least one emitter layer and at least one collector layer, said at least one base layer being arranged between said at least one emitter layer and said at least one collector layer so that the current flowing in direction vertically to said substrate flows through said emitter layer, said collector layer and said base layer, and wherein said base layer is arranged between the lowest layer of said first layer stack nearest to said substrate and the topmost layer of said second layer stack.