High-Precision Laser Self-Mixing Displacement Sensor Based on Orthogonal Signal Phase Multiplication Technique

A new signal processing method named orthogonal signal phase multiplication (OSPM) is proposed, which is used to improve the precision of vibration measurement in a phase-modulating self-mixing interferometer (SMI). The modulated signal is acquired by an electro-optic modulator, which is placed in t...

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Bibliographic Details
Published in:Photonics 2023-05, Vol.10 (5), p.575
Main Authors: Wang, Xiulin, Zhong, Zhengjian, Chen, Hanqiao, Zhu, Desheng, Zheng, Tongchang, Huang, Wencai
Format: Article
Language:English
Subjects:
Accuracy
Algorithms
Fourier transforms
Interferometry
Lasers
Measurement techniques
Methods
micro-displacement reconstruction
Optical components
phase modulation
phase multiplication
self-mixing interference
Sensors
Signal processing
Vibration
Vibration measurement
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Summary:A new signal processing method named orthogonal signal phase multiplication (OSPM) is proposed, which is used to improve the precision of vibration measurement in a phase-modulating self-mixing interferometer (SMI). The modulated signal is acquired by an electro-optic modulator, which is placed in the external cavity. Higher measurement precision is realized by performing the phase multiplication algorithm on the orthogonal signals extracted from the harmonic components of the signal spectrum. Theoretically, the displacement reconstruction precision of OSPM is higher than that of conventional modulation methods, and it can be continuously improved by increasing the multiplication times. The feasibility and performance of the proposed method are verified by simulated signals and confirmed by experiments; the absolute error is less than 11 nm, and relative error is less than 0.75%, within the amplitude range from 661 nm to 2013 nm. This method does not involve additional optical elements, and its effectiveness meet the requirements for real-time high-precision measurements.
ISSN:2304-6732
2304-6732
DOI:10.3390/photonics10050575