Patent ID: 7133430

Claim:
An AlGaAs-based ridge-stripe semiconductor laser element having a stacked structure formed on a GaAs substrate, said stacked structure comprising: an Al y Ga 1-y As (0<y<1) cladding layer having a same conductivity type as said substrate, an Al x Ga 1-x As (0<x<1) cladding layer having a same conductivity type as said substrate; a non-doped active layer section having an Al x Ga 1-x As (0<x<1) first cladding layer having a conductivity type opposite to said substrate and an Al z Ga 1-z As (0z≦1) etching stop layer; an Al x Ga 1-x As (0x<1) second cladding layer having a conductivity type opposite to said substrate; an Al y Ga 1-y As (0<y<1) third cladding layer having a conductivity type opposite to said substrate; and a GaAs contact layer having a conductivity type opposite to said substrate, wherein said second cladding layer, said third cladding layer and said contact layer are formed as a stripe-patterned ridge, and an Al compositional ratio “z” of said etching stop layer, an Al compositional ratio “x” of said first cladding layer and said second cladding layer, and an Al compositional ratio “y” of said third cladding layer satisfy the relations x<z and x<y, where a difference between “x” and “z” is set to 0.025 or more.