Abstract

Most high frequency quantum well lasers reported so far have been limited either by insufficient power or by electrical parasitics, but this paper addresses the ultimate bandwidth limit, set by damping due to gain suppression: $f_{\max }=\sqrt{8}\pi lk$, where k = Γ/f_O², where f_O is the resonance frequency, and where Γ is the damping rate. This limit is ~30 GHz for bulk lasers but is highly variable for quantum well lasers. Estimated values range from 4 GHz (for 1-μm strained SQW lasers¹) to 70 GHz (for 1.5μm strained MQW lasers²). Clearly it is important to understand the cause of this damping, not only for fundamental principles but also to guide the optimization of high frequency quantum well lasers.

© 1991 Optical Society of America