Theory for voltage modulation of transistor lasers using Franz-Keldysh absorption in the presence of optoelectronic feedback

Abstract

Compared with typical diode lasers (DLs), transistor lasers (TLs) support not only current-controlled but also voltage-controlled modulation. In this work, we theoretically investigate the small-signal voltage modulation of TLs based on the Franz-Keldysh (F-K) absorption and related optoelectronic feedback. In addition to the conventional rate equations relevant to DLs, our model physically includes various F-K effects. An optically induced current due to the F-K absorption may dramatically alter the voltage response of TLs. A model composed of the intrinsic optical response and an electrical transfer function which is fed back by this optical response is proposed to explain the true behaviors of voltage modulation in TLs. (C) 2016 Optical Society of America