Patent ID: 6621845
Filing Date: 2003-09-16
Classification: B82Y,H01S

Abstract:
A semiconductor laser device comprising:a GaAs substrate of a first conductive type; a lower cladding layer of said first conductive type having a first refractive index and being formed above said GaAs substrate; a lower optical waveguide layer formed above said lower cladding layer; a compressive strain quantum well active layer made of Inx3Ga1âˆ’x3As1âˆ’y3Py3 and formed above said lower optical waveguide layer, where 03&lE;0.4 and 0&lE;y3&lE;0.1; a first upper optical waveguide layer made of Inx2Ga1âˆ’x2As1âˆ’y2Py2 and formed above said compressive strain quantum well active layer, where x2=(0.49Â±0.01)y2, 0&lE;x2&lE;0.3, and said first upper optical waveguide layer has a second refractive index; a first etching stop layer made of Inx9Ga1âˆ’x9P of a second conductive type and formed above said first upper optical waveguide layer, where 0&lE;x9&lE;1; a second etching stop layer made of Inx1Ga1âˆ’x1As1âˆ’y1Py1 and formed on said first etching stop layer other than a stripe area of the first etching stop layer so as to form a first portion of a stripe groove realizing a current injection window, where x1=(0.49Â±0.01)y1 and 0&lE;x1&lE;0.3; a current confinement layer made of In0.49Ga0.51P of the first conductive type and formed above said second etching stop layer so as to form a second portion of said stripe groove; a second upper optical waveguide layer made of AlGaAs formed so as to cover said current confinement layer and said stripe groove; an upper cladding layer of said second conductive type, made of one of AlGaAs and Inx4Ga1âˆ’x4As1âˆ’y4Py4 and formed over said second upper optical waveguide layer, where x4=(0.49Â±0.01)y4, 0.9&lE;y4&lE;1; a contact layer of said second conductive type; a first electrode formed on an exposed surface of said GaAs substrate; and a second electrode formed on said contact layer; wherein an absolute value of a first product of a first strain and a thickness of said compressive strain quantum well active layer is equal to or smaller than 0.25 nm, and each of said lower cladding layer, said lower optical waveguide layer, said first and second upper optical waveguide layers, said first and second etching stop layers, said current confinement layer, said upper cladding layer, and said contact layer has such a composition as to lattice-match with GaAs.