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• Chinese Optics Letters
• Vol. 20, Issue 2, 021202 (2022)
Di Wu1, Lei Yang1, Xiuliang Chen1, Zhaohui Li1、*, and Guang Wu1、2
Author Affiliations
• 1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
• 2Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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Abstract

We demonstrate a multi-channel pseudo-random coding single-photon ranging system. A pseudo-random multiplexing technique is proposed, which realizes multi-channel pseudo-random ranging only by using one single-photon detector and processing circuit. Compared with the time division multiplexing technique, it will not reduce the maximum unambiguous range while increasing the number of the ranging channel. Eight-channel pseudo-random coding single-photon ranging was realized with the ranging accuracy better than 2 cm. Moreover, photon counting imaging was realized through scanning the laser beams of the eight-channel pseudo-random ranging system. There is no crosstalk between channels, which is suitable for multi-beam long-distance single-photon Lidar.

1. Introduction

Single-photon ranging attracted much attention in the field of vehicle-mounted Lidar[13], satellite-ground measurement[4], and unmanned aerial vehicle Lidar[5,6]. Most single-photon ranging systems use the time-of-flight (TOF) method[7,8]. The time correlated single-photon counting (TCSPC)[911] technique is widely used to extend the measurement sensitivity and precision, when the laser pulse energy remains unchanged. On the other hand, the multi-beam method is introduced for single-photon Lidar to improve the measurement speed[1215]. The Leica SPL100 splits a 532 nm laser into $10×10$ laser beams and receives the echo photons by a $10×10$ single-photon detection array of photomultiplier tubes (PMTs)[16]. It increases the sampling rate by increasing the number of laser beams. However, the detection array is complicated and expensive. In order to simplify the multi-beam detection system, researchers have proposed technologies such as time division multiplexing (TDM)[17,18] or repetition frequency multiplexing[19] to improve the utilization of the detection system, so that one single-photon detector (SPD) and timing circuit can detect the echo photons of multiple beams at the same time. The TDM method uses multiple pulsed lasers with the same repetition frequency and different pulse delays. In order to distinguish the echo photons of each laser beam, it is necessary to ensure that the echo photons of the previous laser beams have been detected before the next laser beam is emitted. If the number of channels increases, the delays between the laser beams should be decreased, resulting in decreasing the maximum unambiguity range.

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Di Wu, Lei Yang, Xiuliang Chen, Zhaohui Li, Guang Wu. Multi-channel pseudo-random coding single-photon ranging and imaging[J]. Chinese Optics Letters, 2022, 20(2): 021202