A research team led by Professor Haizhi Song from Southwest Institute of Technical Physics of China proposed a design of a near-infrared free-running single photon counting integrated module based on InGaAs/InP Negative Feedback Avalanche Diode (NFAD). InGaAs/InP NFAD achieves self-quenching through an integrated negative feedback resistor and is a new type of high-sensitivity all-solid-state semiconductor device based on the structure of Single Photon Avalanche Diode (SPAD). The module includes active quenching and extraction circuits, sampling and processing circuits, upper computer software design, TEC etc. It is designed to serve a NFAD adopting InGaAs/InP materials in Separate Absorption, Grading, Charge and Multiplication (SAGCM) structure and operating in Geiger mode. In this module, researchers specifically designed a fully differential amplifier and comparator to exploit the performance of NFAD by detecting and extracting the weak avalanche signal and converting it into TTL pulses. The avalanche detection discrimination threshold voltage is adjustable by an external high-precision DAC and the dead time can be programmed through FPGA. The system module provides timing logic to avoid false counting caused by coupling noise of the differential amplifier. By developing Graphical User Interface (GUI) program, parameters configuration, real-time counting data display and various application requirements can be achieved. The fabricated module exhibits good NFAD performance with Photon Detection Efficiency of 7.9% and 15.8%, Dark Count Rate of 1.37 kHz and 1.06 kHz, and Afterpulsing Probability of 34.2% and 16.8% at 223 K, 1550 nm with dead time of 200 ns and 1 μs, respectively. This indicates that a near-infrared single photon counting system with fast detection speed, short quenching time, flexible dead time tuning, small size and high integration will soon emerge to support lidar and quantum information facilities.

This research outcome was published at the International Conference on Optoelectronic Information and Functional Materials (OIFM 2023) held in San Francisco, California, USA on August 6, 2023.