Absorptive-Grating Gain-Coupled Distributed-Feedback MQW Lasers with Low Threshold Current and High Single-Longitudinal-Mode Yield

Publisher Website
Google Scholar
Abstract
Although gain-coupled (GC) distributed-feedback (DFB) lasers of the absorptive-grating type have several merits over those of gain-grating type, there have been disadvantages which include threshold increase due to excess absorption, parasitic index coupling, and nonlinear operation. In this paper we describe some new concepts to cope with these problems, namely, grating duty-factor optimization, a conduction-type inverted absorptive grating, and an anti-phase index grating. We have applied these schemes to GaAlAs/GaAs multiple-quantum-well (MQW) GC DFB lasers. Consequently, low threshold current, high slope efficiency, high side-mode suppression railo, narrow linewidth, and high single-mode yield have been achieved concurrently in as-cleaved devices.