Optical Bandwidth Enhancement Of Heterojunction Bipolar Transistor Laser Operation With An Auxiliary Base Signal

摘要

We report the improvement, from 10.5 to 22 GHz, in the optical modulation bandwidth of a quantum-well (QW) heterojunction bipolar transistor laser (TL) by the use of an ac auxiliary base signal. Because of the three-terminal form of the TL, an auxiliary signal can be used to peak the photon output, e.g., stimulated recombination which simultaneously reduces the operating current gain, β(=I_(CO)/I_(BO)), and increases the laser differential gain. A shorter effective base carrier lifetime, t, owing to the increased QW recombination rate (stimulated recombination), enhanced carrier transport to the "faster" QW collector (reduced β) and differential gain, result in a higher 3 dB bandwidth (f_(3 dB)=1/2πt).