Reactively ion etched nonuniform-depth grating for advanced DFB lasers

Abstract

An ethane (C/sub 2/H/sub 2/) reactive ion etching (RIE) technique that offers smooth-etched morphology, high controllability of depth, and anisotropic geometries for forming a nonuniform-depth grating on an InP substrate is discussed. The fabrication of a lambda /4-shifted multiple quantum well (MQW) distributed feedback (DFB) laser with a 900 mu m cavity and a nonuniform-depth grating is described. It is shown that the larger threshold gain difference predicted by theory is obtained despite strong hole-burning.<>