Optical semiconductor device and fabrication method therefor

Abstract

An optical semiconductor device such as, for example, a quantum dot SOA and a fabrication method therefor are disclosed wherein an active layer and a current constriction structure can be formed leftwardly and rightwardly symmetrically to minimize the polarization dependency. The fabrication method for an optical semiconductor device includes the steps of forming a semiconductor layer on a semiconductor substrate, forming a groove by removing the semiconductor layer at an opening of a mask, forming a first clad layer in the form of a projection having two symmetrical inclined faces in the groove by selective growth by using the mask as a selective growth mask, forming an active layer on the two inclined faces of the first clad layer, and removing the mask and burying the active layer with a second clad layer.