Planar concave grating demultiplexer fabricated on a nanophotonic silicon-on-insulator platform

We show that a nanophotonic silicon-on-insulator (SOI) platform offers many advantages for the implementation of planar concave grating (PCG) demultiplexers, as compared with other material systems. We present for the first time the design and measurement results of a PCG demultiplexer fabricated on a nanophotonic SOI platform using standard wafer scale CMOS processes including deep-UV lithography. Our PCG device has four wavelength channels with a channel spacing of 20 nm and a record-small footprint of 280 x 150 mu m. The on-chip loss is 7.5 dB, and the crosstalk is better than -30 dB.