Patent ID: 7180930
Filing Date: 2007-02-20
Classification: H01S

Abstract:
1. A distributed feedback (DFB) semiconductor laser device comprising: a laser cavity disposed between a first facet and a second facet of said laser device for emitting laser therefrom in an axial direction of said laser cavity; and a diffraction grating extending parallel to said axial direction for feedback of the laser to said laser cavity, said diffraction grating including a number (t) of corrugation patterns, which are arranged in said axial direction at a specified pitch except for some of said corrugation patterns, wherein: the number (t) of said corrugation patterns satisfies the following relationship: wherein Lg, λ the order of said corrugation patterns in said diffraction grating is not an integer; some of corrugation patterns are omitted at a constant pitch in the axial direction of the laser cavity; and the laser cavity has a cavity length of 500 micrometers or above.