Compact demultiplexer using cascaded planar concave grating and ring resonators on SOI

We present a compact demultiplexer based on cascaded planar concave grating and ring resonators. The demultiplexer has 28 channels, with 1 nm channel spacing. The device was fabricated on a silicon-on-insulator (SOI) platform using CMOS compatible deep UV lithography. The size of the structure is 1.5 times 3 mm. Insertion loss is 15 dB, channel to channel variation is 5 dB.