Low-Timing-Jitter GHz-Gated InGaAs/InP Single-Photon Avalanche Photodiode for LIDAR

Abstract

InGaAs/InP single-photon avalanche diodes (SPADs) attract increasing attention for the infrared light detection and ranging (LIDAR) due to the low-cost and compact-size construction. Although constant endeavor has been dedicated to improve the dead time and timing jitter, it remains challenging to implement high-speed and high-resolution LIDAR. Here, we develop a high-performance GHz-gated InGaAs/InP APD operated in the quasi-free-running mode, while its gating signal is unlocked from the light source. The used low-pass filtering technique enables us to continuously adjust the repetition frequency of the gate for carefully optimizing photon detection efficiency (PDE) and timing jitter. Increasing the gates’ repetition frequency from 1 GHz to 2.75 GHz, the PDE improves dramatically from 2.02% to 3.30%, while the timing jitter drops from 156 ps to 114 ps. Furthermore, we verify that changes in the PDE have little effect on the timing characteristics, making the SPAD more suitable for LIDAR with large dynamic range. Meanwhile, the dead time is about 4 ns, which is much shorter than that of the SPAD working in the free-running mode, guaranteeing rapid mapping of targets. Finally, as a proof-of-principle demonstration, the InGaAs/InP SPAD is used in a time-of-flight LIDAR system, which demonstrates a sub-centimeter depth resolution directly.