An n-InP cladding layer, a GRIN-SCH-MQW active layer, a p-InP cladding layer, p-InGaAsP contact layer and a p-side electrode are laminated sequentially on an n-InP substrate. Moreover, a film having high reflectivity is laminated on a reflection side end surface, and a transmission film is laminated on an emission side end surface. The transmission film has a first film and a second film. The second film is composed of an equivalent film composed of three layers.