Design of Polarization-Independent Si-Wire-Waveguide Wavelength Demultiplexer for Optical Network Unit

We report the design of a compact wavelength demultiplexer using a Si wire waveguide as an optical network unit. We use a Mach–Zehnder lattice interferometeric filter structure to attain a flat-top response. The large wavelength dispersion of the Si wire waveguide requires special design considerations for widely separated wavelength channels. Preliminary experimental results obtained by the device fabricated in a silicon-on-insulator wafer showed a flat-top filter response.