Patent ID: 7076134

Claim:
A method of attenuating an optical signal propagating along a waveguide in a substantially planar lightwave circuit, said method comprising: providing a variable optical attenuator structure comprising a waveguide core, a cladding, an electrooptic polymer, and a set of control electrodes, wherein said electrooptic polymer is configured to define an index of refraction that varies under application of a suitable electric field generated by said control electrodes, said polymer comprises an un-poled electrooptic polymer selected such that said variation of said index of refraction is dominated by an electrooptic response resulting from the Kerr Effect, said core, said cladding, and said electrooptic polymer are configured such that an increase in said index of refraction of said polymer causes a substantial portion of an optical signal propagating along said waveguide core to couple into a relatively high index region of said electrooptic polymer, said core, said cladding, and said electrooptic polymer are configured such that said coupled portion of said optical signal does not return to said waveguide core, said waveguide core defines a core thickness occupying a core layer of said planar lightwave circuit, said core layer of said planar lightwave circuit extends generally parallel to the plane of said planar lightwave circuit, and said electrooptic polymer and said set of control electrodes are configured to define said high index region substantially above said core layer; generating said electric field in said electrooptic polymer by applying a driving voltage to said control electrodes; and controlling attenuation in said variable optical attenuator structure by varying said driving voltage.