Patent ID: 7136553

Claim:
A tunable demultiplexer comprising: an input waveguide for guiding beams having a plurality of different wavelengths to an optical deflector, wherein the end of the input waveguide through which the beams enter into the optical deflector is defined as an actual light source, the optical deflector comprising: a peripheral region having a first effective refractive index; and a non-prism deflection pattern region having a second effective refractive index and having a predetermined nonlinear shape bounded by the peripheral region wherein the beams in the deflection pattern region radially spread out from the actual light source, wherein the radially spreading beams are deflected by an angle at the nonlinear boundary as the deflected radially spreading beams propagate in the peripheral region, wherein the deflected radially spreading beams in the peripheral region is equivalent to non-deflected beams radially spreading from a virtual light source the location of which virtual light source is different from the location of the actual light source, wherein the location of the virtual light source is variable by varying the second effective refractive index by which the angle of deflection is controlled, and wherein the deflected radially spreading beams propagate through the peripheral region to a grating; the grating for diffracting the deflected radially spreading beams according to different wavelengths; and output waveguides for selecting and outputting the diffracted beams from the grating.