Lateral and Longitudinal Mode Discrimination in Index-Guided Circular Ring Semiconductor Lasers

TLDR: In this article, a WKB analysis of mode structure and thresholds of ridge-waveguide semiconductor lasers is presented, and coupled-mode theory of radially coupled dual ring lasers is discussed.

Abstract: Circular ring semiconductor lasers are promising sources of coherent light for integrated optoelectronics. There have been a number advances in these lasers [1-3]. We believe that the structures with relatively smal index step (Δn=0.1-0.2), for instance ridge- waveguide of buried heterostructure ring lasers, will have better performance characteristics than the devices with deep etching through active region. We present in this paper a WKB analysis of mode structure and thresholds of ridge-waveguide semiconductor lasers, and coupled-mode theory of radially coupled dual ring lasers. We show strong suppression of higher-order lateral modes due to leakage. We show also that radial coupling of concentric two ring lasers results in discrimination of longitudinal modes.