Patent ID: 7046435

Claim:
A reflective semiconductor optical amplifier comprising: a substrate; an optical waveguide with a buried heterostructure formed by sequentially laminating a lower cladding, an active layer, and an upper cladding on the substrate, and including a straight line waveguide region having an end, a curved waveguide region, and a tapered waveguide region having an end; a current blocking layer formed around the optical waveguide to prevent electric current from flowing to a region other than the active layer of the optical waveguide; a trench formed by selectively etching portions of the current blocking layer and the substrate around the optical waveguide in order to reduce parasitic capacitance due to electric current leaked around the active layer; a window region formed on the end of the tapered waveguide region, the window region having an end; an anti-reflection surface formed on the end of the window region; and a high-reflection surface formed on the end of the straight line waveguide region to reflect inputted light.