Extremely small polarization independent phased-array demultiplexers on InP

Compact, polarization insensitive phased-array wavelength demultiplexers are demonstrated with a deep ridge waveguide. Good agreement with the modeling is found for the birefringence and the refractive index. Zero birefringence is effectively obtained around 1.53 μm. The guiding structure allows curvatures of 100 μm; thus, the grating size of the 4- and 16-channel demultiplexers is reduced to 0.33×0.30 and 1.1×1.1 mm², with crosstalk below -16 and -14 dB respectively. These are the smallest demultiplexers reported to date.