4-channel wavelength flattened demultiplexer integrated with photodetectors

We report the first 4-channel wavelength demultiplexer with flattened response, monolithically integrated with photodetectors. The demultiplexer is realized in InP-InGaAsP and operates around a centre wavelength of 1533 nm with a wavelength spacing of 2.0 nm. The response is flat within 1 dB for a 1.2 nm band centered around the transmission wavelength. Crosstalk remains below -20 dB. On-chip losses are estimated at -6.0 dB. Photodetector capacitances and dark currents at -5 V bias are 0.5 pF and better than 8 nA respectively