Patent ID: 6788725
Filing Date: 2004-09-07
Classification: B82Y,H01S

Abstract:
A semiconductor laser device comprising:an InP substrate of a first conductivity type; a first cladding layer of the first conductivity type disposed on the InP substrate; an active layer including a multiple quantum well structure disposed on the first cladding layer and having uniformly flat upper and lower boundary surfaces in an optical waveguide direction; a second cladding layer of a second conductivity type disposed on the active layer; a diffraction grating layer having a phase-shifting structure in the optical waveguide direction, between the active layer and one of the first and second cladding layers, wherein the diffraction grating layer has a length L in the optical waveguide direction greater than zero but not exceeding 260 &mgr;m; mean coupling factor &kgr; of the diffraction grating layer is at least 150 cmâˆ’1; and 5.6>&kgr;L>3.0; and power supply electrodes opposite each other, wherein the phase-shifting structure is interposed between the power supply electrodes.