Operation principle of the InGaAsP/InP laser transistor

A laser transistor functions both as a semiconductor laser and a heterojunction bipolar transistor. It generates stimulated emission light from the base region. We have obtained, typically, a maximum laser power of 3 mW, a current gain of 2000, and a transition frequency of 2.5 GHz for the fabricated devices. We show that the novel light output control can be obtained by changing its collector voltage. Both laser output and collector current can also be simultaneously controlled by changing the base current.