Optical semiconductor device

摘要

A semiconductor laser chip according to the present invention comprises: a p-type InP substrate; an InGaAsP active layer (optical waveguide) formed on said substrate; a p-n-p InP block layer formed on said substrate; a contact layer formed thereupon; an insulating film formed on said contact layer; a front surface electrode formed on said insulating film; a pair of alignment marks formed at the same time of the optical waveguide; and a back surface electrode formed on said substrate. The alignment marks are formed from the same material, i.e., the same crystal as said optical waveguide. Accordingly, it is possible to improve precision of the relative position between said optical waveguide and said alignment marks.