Miniature integrated spectrometer fabricated on a silicon-on-insulator substrate

We demonstrate a compact and cost-effective 30-channel integrated spectrometer fabricated on a nanophotonic silicon-on-insulator (SOI) platform. The spectrometer consists of a planar concave grating (PCG) demultiplexer with heterogeneously integrated III–V photodetectors. The device has a resolution of 3.2nm and a small footprint of ∼2mm². The photodetectors have a dark current of ∼3nA at 5V bias and a responsivity of 1A/W. The on-chip loss for the central PCG channels is 3dB, resulting in an on-chip responsivity of 0.5A/W.