Nonlinear calibration of frequency modulated continuous wave LIDAR based on a microresonator soliton comb

Abstract

Traditional frequency modulated continuous wave (FMCW) LIDAR ranging is based on heterodyne detection, calculating unknown distance by extracting the frequency of the interference signal, while the main error source is frequency modulation (FM) nonlinearity. In this paper, a ranging system based on a microresonator soliton comb is demonstrated to correct the nonlinearity by sampling the ranging signals at equal frequency intervals, producing a ranging error lower than 20 µm, while at the range of 2 m. Advantages of fast data acquisition, light computation requirements, and a simple optical path, without long optical fiber, give this method a high practical value in precision manufacturing.

High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

“…The experimental results show that in indoor environment, the ranging error is better than 13.96 μm, and the standard deviation is less than 17.59 μm when comparing with commercial interferometers. Also, the minimum Allan deviation of this position is 65 nm at 10.24 s. Compared with the nonlinear calibration scheme based on the soliton microresonator comb in our previous work, the scheme proposed in this study has better ranging accuracy, simpler system, higher integration, and wider applicability. Even at an outdoor distance of 438 m, the minimum Allan deviation is 420 nm at 10.24 s, realizing high accuracy measurement at any distance.…”

“…The third is based on the OFCs. , With the development of the OFC locking technology, each comb of the OFCs can be precisely locked, which provides a stable frequency reference for measurement. By detecting the beat frequency of FMCW laser and OFCs, the phase information can be obtained by phase unwrapping, and the frequency value of the beat signal can be obtained by differentiating.…”

“…This method can realize the real-time frequency measurement but need precision measuring the self-beating frequency of OFC, which has higher requirements on hardware. In 2021, Jia et al improved this scheme by using high repetition soliton microcombs − to calibrate the nonlinear problems in FMCW ranging and eliminating the detection of self-beating frequency of soliton microcombs with a high repetition rate. The measurement accuracy is better than 20 μm in the range of 2 m .…”

“…In 2021, Jia et al improved this scheme by using high repetition soliton microcombs − to calibrate the nonlinear problems in FMCW ranging and eliminating the detection of self-beating frequency of soliton microcombs with a high repetition rate. The measurement accuracy is better than 20 μm in the range of 2 m . However, it is necessary to build a complex optical system to accurately adjust the detuning and power of the laser, and the survival time of the soliton comb is also limited, which limits the application prospect of this scheme.…”

Phase Unwrapping and Frequency Points Subdivision of the Frequency Sweeping Interferometry Based Absolute Ranging System

“…Moreover, an optical frequency comb can calibrate the sweeping frequency of a continuous wave (CW) laser [23]. Jia et al [24] corrected the nonlinearity by sampling the ranging signals at equal frequency intervals with a microresonator soliton comb. However, this measurement method is not suitable for industrial environments because of its complex structure and considerately high cost [25].…”