Theoretical investigation of DFSI with immunity to both Doppler effect and frequency-sweep nonlinearity

Frequency-swept interferometry (FSI) is a well-known ranging technique, but it suffers from three problems, namely, the Doppler effect, the frequency-sweep nonlinearity, as well as the slow frequency-sweep rate. The first two problems hinder the measurement accuracy, while the third problem limits t...

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Bibliographic Details
Published in:Optoelectronics letters 2022-11, Vol.18 (11), p.662-667
Main Authors: Zheng, Feiteng, Shao, Bin, Sun, Shufeng, Zhang, Wu, Tan, Qinggui, Zhang, Wei
Format: Article
Language:English
Subjects:
Doppler effect
Error analysis
Interferometers
Interferometry
Lasers
Nonlinearity
Optical Devices
Optics
Photonics
Physics
Physics and Astronomy
Signal processing
Vibration meters
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Summary:Frequency-swept interferometry (FSI) is a well-known ranging technique, but it suffers from three problems, namely, the Doppler effect, the frequency-sweep nonlinearity, as well as the slow frequency-sweep rate. The first two problems hinder the measurement accuracy, while the third problem limits the measurement rate. In this paper, we present a dynamic FSI (DFSI) that solves these three fundamental problems simultaneously. The DFSI consists of two auxiliary interferometers (AU1 and AU2) and two measurement interferometers (FSI and frequency-fixed interferometry (FFI)). We use FSI to obtain the Doppler and nonlinearity affected ranging signal, AU1 to monitor the frequency-tuning nonlinearity in the frequency-swept laser (FSL), and FFI and AU2 to constitute a laser vibrometer for monitoring the target motion-induced Doppler effect. Then, a novel signal fusion processing technique is applied to reconstruct the real dynamic distance from the above-measured signals. The dynamic ranging error caused by the Doppler effect and frequency-sweep nonlinearity in FSI can be eliminated and the dynamic distance at each sampling point can be obtained. The validity of this method is demonstrated by numerical experiments.
ISSN:1673-1905
1993-5013
DOI:10.1007/s11801-022-2090-x