Patent ID: 7454111

Claim:
A waveguide optical device comprising: a waveguide comprising a core layer and a guide layer, wherein said core layer and said guide layer are formed from semiconductors having zinc blend crystal structures; wherein: said waveguide comprises fundamental mode waveguides and a multimode waveguide which has a width greater than a width of said fundamental mode waveguides; said multimode waveguide includes side faces structured from one or more of: planes equivalent to a (100) plane of said semiconductors, planes forming an angle of inclination of 7° or less with planes equivalent to the (100) plane, in a direction parallel to a surface formed between said core layer and said guide layer; and planes forming an angle of inclination with planes equivalent to the (100) plane, in a direction normal to the surface formed between said core layer and said guide layer; and said waveguide optical device further comprises a semiconductor layer, wherein said multimode waveguide is embedded as a buried layer within said semiconductor layer.