Integrated optical semiconductor device.

摘要

In an integrated optical semiconductor device having an InGaAsP optical waveguide (13) and an InGaAs light absorption layer (14) integrated together therein, the light absorption layer (14) is formed to become gradually thicker in a traveling direction of light in the optical waveguide so that the effective absorption coefficient of the light absorption layer (14) with respect to the optical waveguide (13) can be set to become gradually larger in the traveling direction in the optical waveguide. <IMAGE> <IMAGE>