Patent ID: 7747122

Claim:
An apparatus comprising: an optical waveguide having a rib region and a slab region, the optical waveguide further having first and second doped semiconductor regions of opposite doping types, the first and second regions adjoining each other at a junction, the junction extending in two different directions along two peripheral sides of the waveguide in the rib region of the waveguide; a first higher doped semiconductor region outside an optical path of the optical waveguide, an inner portion of the first higher doped region adjoining and coupled to the first doped region of the optical waveguide, the first higher doped region having a higher doping concentration than a doping concentration within the optical path of the optical waveguide; and a second higher doped semiconductor region outside an optical path of the optical waveguide, an inner portion of the second higher doped region adjoining and coupled to the second doped region of the optical waveguide, the second higher doped region having a higher doping concentration than a doping concentration within the optical path of the optical waveguide.