Patent ID: 6259718
Filing Date: 2001-07-10
Classification: H01S

Abstract:
A distributed feedback laser device comprising an optical waveguide having one end facet serving as a beam emission surface and the other end facet serving as a reflection surface, an active layer formed between said beam emission and said reflection surfaces, and a diffraction grating formed in said optical waveguide so as to extend along a lengthwise direction of said active layer, wherein:said active layer has a first region extending in the lengthwise direction of said active layer and located nearer to said beam emission surface than to said reflection surface and a second region extending in the lengthwise direction of said active layer, adjoining said first region, and located nearer to said reflection surface than to said beam emission surface, said first region being narrower in width than said second region;said diffraction grating having first and second portions located along said first and said second regions, respectively, said first portion being longer in pitch than said second portion.