Planar Concave Grating Demultiplexers on an InP-Membrane-on-Silicon Photonic Platform

We present measurement results of a 0.25
${\rm mm}^{2}$
footprint eight-channel planar concave grating demultiplexer fabricated in a 300-nm-thick InP membrane adhesively bonded to silicon. The measured cross-talk between the different channels of the device is better than
${-}{\rm 18}~{\rm dB}$
, while the insertion loss is 2.8 dB. The power non-uniformity between the channels is 1.2 dB.