Embodiments of an optical detection apparatus are disclosed which may include one or more of a waveguide, a trench formed in the waveguide, a reflective surface, and a photodetector. The waveguide may be formed in a semiconductor substrate to propagate an optical signal received at a first end of the...http://www.google.ca/patents/US8057108?utm_source=gb-gplus-sharePatent US8057108 - Method and apparatus to generate and monitor optical signals and control power levels thereof in a planar lightwave circuit
