Patent ID: 6873637

Claim:
A semiconductor laser element comprising: a substrate of a first conductive type; a lower cladding layer of the first conductive type, formed above said substrate; a lower optical waveguide layer formed above said lower cladding layer, and made of In 0.49 Ga 0.51 P which is undoped or the first conductive type; an active layer which is formed above said lower optical waveguide layer, and made of In x3 Ga 1-x3 As 1-y3 P y3 lattice-matching with GaAs, where 0<x3≦0.3 and 0≦y3≦0.5; an upper optical waveguide layer formed above said active layer, and made of In 0.49 Ga 0.51 P which is undoped or a second conductive type; and an upper cladding layer of the second conductive type, formed above said upper optical waveguide layer; wherein said lower optical waveguide layer has a bandgap which gradually decreases with increase in elevation within the lower optical waveguide layer, and said upper optical waveguide layer has a bandgap which gradually increases with increase in elevation within the upper optical waveguide layer.