Patent ID: 7263114

Claim:
A semiconductor laser diode comprising: an active layer, wherein the active layer is composed of a compound semiconductor of GaInP series; an upper clad layer formed above the active layer, wherein the upper clad layer is composed of p-(Al 0.7 Ga 0.3 ) 0.5 In 0.5 P; a first lower clad layer formed below the active layer; a second lower clad layer formed under the first lower clad layer; and a substrate formed beneath the second lower clad layer, wherein a refractive index of the first lower clad layer is identical with a refractive index of the upper clad layer and is lower than a refractive index of the second lower clad layer and wherein the first and second lower clad layers are composed of compound semiconductors of n-AlGaInP series and wherein the second lower clad layer is composed of n-(Al 0.68 Ga 0.32 ) 0.5 In 0.5 P.