Semiconductor light emitting device in which high-power light output can be obtained with a simple structure

Semiconductor light emitting device includes a semiconductor substrate formed from indium phosphide; an active layer at an upper side of the substrate; and an n- and p-type cladding layers formed from indium phosphide for holding the active layer. Semiconductor light emitting device (30) includes a semiconductor substrate (11) formed from indium phosphide; an active layer (14) at an upper side of the substrate; and an n- and p-type cladding layers formed from indium phosphide for holding the active layer. The n-type cladding layer (32) is formed from indium gallium arsenic phosphide. The refractive index of n-type cladding layer is (na) and that of the p-type cladding layer is (nb), such that na is greater than nb. The optical loss by intervalence band light absorption at the p-type cladding layer (18) is suppressed when the distribution of light generated by the active layer is deflected to the n-type cladding layer.