A novel 350 nm CMOS optical receiver based on a current-assisted photodiode detector

Integrating an optical receiver in CMOS optimized for near infrared light (NIR) remains appealing but at the same time challenging due to the deep photon penetration depth. A novel implementation of a light detector is demonstrated in a 350 nm CMOS technology, whereby, through adding a majority current with associated electric field distribution in the silicon detection volume, photo-generated minority electrons get quickly guided to the center of this volume. In the center, a tiny PN junction collects the photo-electrons. The detection speed subsequently increases, NIR light is received with improved responsivity and the detector capacitance gets drastically reduced to femtofarad level. The latter improvement also increases signal-to-noise performance and can be used to trade-off with other design parameters to improve global performance of the opto-electronic system. An optical datacom receiver at 1 Gbps is demonstrated at NIR-wavelength for proving useful Current-Assisted Photodiode detector operation in an actual CMOS system