Large signal analysis of multiple quantum well transistor lasers: Investigation of imbalanced carrier and photon density distribution

Abstract

In this paper, we present a large signal and switching analysis for the Heterojunction Bipolar Transistor Laser (TL) to reveal its optical and electrical behavior under high current injection conditions. Utilizing appropriate models for carrier transport, nonlinear optical gain and optical confinement factor (OCF), we have simulated the large signal response of the HBTL in relatively low and high modulation frequencies. Our results predict that for multiple quantum well structures at low frequencies there should not be a difference in carrier density either the photon density. However, carrier concentration can be differently distributed between subsequent wells in case of a high speed yet large signal input. This leads to increased linewidth instead as it depends on {\Delta}Nqw. We show the effect of different structural parameters on the switching behavior by performing a switching analysis of the Single Quantum Well (SQW) and Multiple Quantum Well (MQW) structures using computationally efficient numerical methods. A set of coupled rate equations is solved to investigate the large-signal and switching behavior of MQW-HBTL. Finally, to have a comprehensive judgment about this optoelectronic device, we introduce a relative performance factor to taking into account all the optoelectronic characteristics such as output power, ac current gain, modulation bandwidth, and base threshold current as well as turn-on time in order to design a suitable TL for Opto-Electronic Integrated Circuits (OEICs).