Multiple-Target Laser Rangefinding Receiver Using a Silicon Photomultiplier Array

In this paper, a silicon photomultiplier (SiPM) array module is evaluated and implemented as the receiver of laser rangefinding experiments to simultaneously measure the range of multiple targets. The array consists of 4 × 4 SiPMs on a single chip. Each SiPM is followed by a transimpedance amplifier to have an adequate output signal voltage. The 4 × 4 array is capable of measuring the range of 16 targets. A SiPM is an avalanche photodiode that operates in Geiger mode, where a huge multiplication factor, as high as 1000000, is obtainable. Thus, it can achieve high sensitivity. Our performance evaluation results show that the sensitivity of the measured SiPMs actually approaches the quantum limit. The SiPM can detect one single photoelectron in the depletion region. Each SiPM has a large active area, i.e., 8 mm², and can collect much more returned light compared with typical silicon avalanche photodiodes (Si-APDs). The rise time of output voltage waveforms from SiPMs varies from 6 to 300 ns, depending on incident light power. The rising edges of output waveforms are compared for time measurement. Using a digital oscilloscope, the time of flight can be measured with 1-ns accuracy. This corresponds to a range resolution of 15 cm.