Polarisation-insensitive arrayed-waveguide gratings using dopant-rich silica-based glass with thermal expansion adjusted to Si substrate

A polarisation-insensitive arrayed-waveguide grating multiplexer is successfully fabricated on an Si substrate by adjusting the thermal expansion of dopant-rich silica-based glass to that of Si. The change in wavelength due to polarisation was kept to within 0.03 nm in a 1×8 arrayed-waveguide grating multiplexer with a flat and wide passband having a 3 dB bandwidth of 0.9 nm and a wavelength spacing of 1.6 nm