Patent ID: 7106922

Claim:
A method, comprising: propagating a multiple wavelength optical signal into a waveguide formed in a semiconductor substrate; splitting the optical signal into first and second substantially equal portions to respectively propagated in second and third planar waveguides formed in the semiconductor substrate; reflecting a selected wavelength of the first portion with a first plurality of silicon and polysilicon interfaces disposed in the second planar waveguide to propagate the selected wavelength in the second planar waveguide; reflecting the selected wavelength of the second portion with a second plurality of silicon and polysilicon interfaces disposed in the third planar waveguide to propagate the selected wavelength in the third planar waveguide; combining the reflected wavelengths from the first and second portions to propagate in a fourth planar waveguide formed in the semiconductor substrate; and filtering the combined reflected wavelengths to transmit the selected wavelength.