On-chip detection and counting of single-photons

We present a fully-integrated CMOS implementation of a sensor chip that contains a single-photon avalanche diode (SPAD), the driving active quenching circuit (AQC) for operating the detector above breakdown, and the digital counting and transmission electronics for remote control and data uploading via a remote computer. The technology is a standard double metal, single-poly 0.8mum-CMOS process. The on-chip photodetector is operated from 2V to 10V above breakdown, in order to detect single photons. After each ignition, the chip quenches and resets the detector with fast transitions of few nanoseconds and holds it off for an adjustable time duration from 5ns to 1 mus. Measurement time slots are generated on-chip and are adjustable in the 3mus-40ms range. Both free-running and gated-detector operation are provided. The achievable photon counting rate is 30Mphoton/s