Abstract—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 × 150 µ m. The on-chip loss is
7.5 dB, and the crosstalk is better than −30 dB.