On-chip silicon nano-slab photodetector integrated wavelength division de-multiplexer in the 850 nm band.

We present an on-chip photodetector integrated wavelength filter on a SiN-on-silicon-on-insulator (SOI) platform in the 850 nm wavelength window. The wavelength filter is designed using an echelle grating with a distributed Bragg reflector as the grating reflectors. We present the design and experimental realization of a six-channel wavelength filter with a channel spacing of 10 nm. Experimentally, we achieve an insertion loss of 4.3 dB and an adjacent channel cross talk of 22 dB. We demonstrate a silicon nano-slab waveguide integrated metal-semiconductor-metal photodetector with a maximum responsivity of 0.56 A/W and dark current of 217 nA. Furthermore, we demonstrate the integration of the echelle grating with the detector and show the feasibility of a CMOS compatible SiN-on-SOI platform for various applications, including short-reach communication and sensing applications.