Ultracompact AWG Using Air-Trench Bends With Perfluorocyclobutyl Polymer Waveguides

Using air-trench bends, an ultracompact 8 times 8 arrayed waveguide grating (AWG) demultiplexer (200-GHz channel spacing) for wavelength-division multiplexing (WDM) has been designed and fabricated with perfluorocyclobutyl (PFCB) core and clad co-polymers on a polyimide substrate. Compared to a conventional AWG in the same material system, the air-trench bend AWG shrinks the required chip area by a factor of 20. The decreased size is a factor in reducing the measured thermal shift to -0.012 nm/degC and decreasing the polarization-dependent wavelength shift to 1.3 nm.