Semiconductor laser element including optical waveguide layers which have gradually varying bandgaps so as to reduce electrical resistance at interfaces

In a semiconductor laser element: a lower cladding layer of a first conductive type, a lower optical waveguide layer made of In.sub.0.49 Ga.sub.0.51 P which is undoped or the first conductive type, an active layer made of In.sub.x3 Ga.sub.1-x3 As.sub.1-y3 P.sub.y3 lattice-matching with GaAs (0 В элементе лазера полупроводника: более низкий слой первого проводного типа, более низкий оптически слой плакирования волновода сделанный In.sub.0.49 Ga.sub.0.51 п которое будет undoped или перво проводно типы, активно слой сделал In.sub.x3 Ga.sub.1-x3 As.sub.1-y3 P.sub.y3 решетк-sopr4ga4 с gaAs (0