Athermalized wavelength division multiplexer/demultiplexer with polymer compensation region and methods of manufacturing

An athermalized optical waveguide circuit device exhibiting reduced signal power losses includes an optical phased-array comprising a plurality of curved waveguide cores of different lengths supported on a planar substrate, wherein each of the waveguide cores of the array includes a first silica segment, a second silica segment, and a central polymer segment connecting the first silica segment with the second silica segment to form a continuous waveguide core. The device is prepared by forming a plurality of adjacent curved silica waveguide cores on a planar substrate, overcladding the silica waveguide cores with a silica overclad, etching at least one groove into a central portion of the optical phased-array through the overclad and silica waveguide cores, forming a plurality of polymer waveguide core segments connecting a first silica waveguide core segment with a corresponding second silica waveguide core segment to form a continuous waveguide core, and overcladding the polymer waveguide core segments to define a composite optical phased-array comprising a plurality of adjacent composite waveguides. The polymer waveguide core segments have a negative variation of index of refraction as a function of temperature to compensate for the positive variation of the silica waveguide core segments, while providing an uninterrupted waveguide with low power loss of optical signals.