SEMICONDUCTOR OPTICAL INTEGRATED DEVICE AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a semiconductor optical integrated device having several semiconductor optical devices integrated on a substrate and a method for manufacturing it by which deformation due to abnormal growth of the semiconductor layer structure in the neighborhood of the boundary between two optically connected semiconductor optical devices is reduced. SOLUTION: In the manufacture of the semiconductor optical integrated device by a butt-joint method, the angle θ of a side wall 11a of a first layer structure 31 after etching is set larger than 90 deg. and below 110 deg., and a form controlling layer 122 of a specified semiconductor material having a thickness (t) on a substrate 10 of 20-150 nm is formed as the lowermost layer of a second layer structure 12 which is formed afterward in such a way that its outer surface 12a on the side wall 11a is a vertical surface. In this way, the abnormal growth of the other layers of the second layer structure 12 is suppressed and the optical coupling between active layers 110 and 120, degradation of device characteristics and the like are prevented.