Analytical Evaluation of Signal-to-Noise Ratios for Avalanche- and Single-Photon Avalanche Diodes

Abstract

Performance of systems for optical detection depends on the choice of the right detector for the right application. Designers of optical systems for ranging applications can choose from a variety of highly sensitive photodetectors, of which the two most prominent ones are linear mode avalanche photodiodes (LM-APDs or APDs) and Geiger-mode APDs or single-photon avalanche diodes (SPADs). Both achieve high responsivity and fast optical response, while maintaining low noise characteristics, which is crucial in low-light applications such as fluorescence lifetime measurements or high intensity measurements, for example, Light Detection and Ranging (LiDAR), in outdoor scenarios. The signal-to-noise ratio (SNR) of detectors is used as an analytical, scenario-dependent tool to simplify detector choice for optical system designers depending on technologically achievable photodiode parameters. In this article, analytical methods are used to obtain a universal SNR comparison of APDs and SPADs for the first time. Different signal and ambient light power levels are evaluated. The low noise characteristic of a typical SPAD leads to high SNR in scenarios with overall low signal power, but high background illumination can saturate the detector. LM-APDs achieve higher SNR in systems with higher signal and noise power but compromise signals with low power because of the noise characteristic of the diode and its readout electronics. Besides pure differentiation of signal levels without time information, ranging performance in LiDAR with time-dependent signals is discussed for a reference distance of 100 m. This evaluation should support LiDAR system designers in choosing a matching photodiode and allows for further discussion regarding future technological development and multi pixel detector designs in a common framework.

A Novel Advancing Signal Processing Method Based on Coupled Multi-Stable Stochastic Resonance for Fault Detection

“…When the noise component is less, the SNR is larger, and the effect of the SR system is better. The SNR output can be explained as follows [45][46][47]…”

Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

“…A typical number of accumulated measurements n meas = 1000 is applied. A distance determination method is assumed that requires a minimum SNR k SN,min = 3 for a successful target detection [21]. The SNR is discussed later in more detail.…”

Towards a solid‐state light detection and ranging system using holographic illumination and time‐of‐flight image sensing

“…Key advantages of SPADs include their high sensitivity, which enables detection in single-photon regime, and their ability to be densely integrated in large arrays. 11 Our imaging sub-system is based on the "QuantiCam" 192 Â 128 SPAD array, 12 which is used for counting and timing the photons of our laser illumination that return after being reflected from the scene. SPAD arrays show high potential in D-ToF LIDAR systems, thanks to their high sensitivity and temporal precision.…”

“…Despite their similarities, the nature of APDs is quite different from that of SPADs. Key advantages of SPADs include their high sensitivity, which enables detection in single‐photon regime, and their ability to be densely integrated in large arrays 11 …”