Multiple-target laser rangefinding receivers using silicon photomultiplier arrays

A silicon photomultiplier (SiPM) is a silicon avalanche photodiode (Si-APD) that operates in Geiger mode. Due to its giant current gain, a SiPM can achieve high detection sensitivity. Thus, it is often used in photon counting where it can detect a single incoming photon. For 2-dimensional applications, SiPM devices in 2-D array are built on the same chip. The SiPM array has found applications in positron emission tomography (PET), scintillation, radiation detection, and gamma-ray cameras. In these applications, giant current gain, high sensitivity, and fast response are essential. In a SiPM array, each SiPM cell (pixel) of the array preserves the performance of a single SiPM device. This opens up a new application in laser range-finding receiver technology which can detect and measure the range of signals reflected from multiple targets. In this design, laser pulses from the transmitter illuminate upon the scene. Optical signals reflected from multiple targets within the field of view are collected and projected onto the SiPM array. Each pixel on the array corresponds to a specific space element on the scene. By measuring the round-trip transit time of the pulse returning from each space element, the range of the target in this space element can be determined.