Lateral mode controlled wide-stripe-lasers by modal reflector

A modal reflector having a high reflective (about 40 percent) region with 24 microns, 48 microns or 96 microns width on the output facet, and applied to gain-guided wide (150 microns) stripe lasers, is described. The partially high reflective region composing the modal reflector consists of an Al2O3/a-Si multilayer whose thickness is determined so as to match in phase between a part of the output from the highly reflective region and remaining outupt from the low reflective ( about 1 percent) region in order to reduce side peaks (fringes) in far-field patterns. Single-lobed far-field patterns for lateral direction as narrow as from 0.88 deg to about 3.5 deg are observed at up to 0.4 W under CW condition.