Semiconductor laser having an AlGaInP cladding layer

摘要

A semiconductor laser includes a GaAs substrate, an active layer made of a semiconductor material having a band gap energy smaller than that of GaAs, and a top clad having an AlGaInP cladding layer. An index antiguiding type semiconductor laser is constituted based on the above structure. The top clad includes a base layer formed on the active layer and a protrusion strip for current injection protruding from the base layer and having an AlGaInP cladding layer. An AlGaInP light diffusion layer with an Al proportion smaller than that of the AlGaInP cladding layer and inclusive of zero is formed on the base layer adjacent to the protrusion strip. The base layer has a thickness so as to allow laser oscillation light to leak out to the light diffusion layer.