Approaches that are, to our knowledge, novel, are proposed in this paper to improve the accuracy performance of self-mixing interferometry (SMI) for displacement measurement. First, the characteristics associated with signals observed in SMI systems are studied, based on which a new procedure is proposed for achieving accurate estimation of the laser phase. The studies also revealed the reasons for the inherent errors associated with the existing SMI-based techniques for displacement measurement. Then, this paper presents a new method for estimating the optical feedback level factor (denoted by C) in real time. Combining the new algorithms for estimating the laser phase and updating C value, the paper finally presents a novel technique for displacement measurement with improved accuracy performance in contrast to existing techniques. The proposed technique is verified by both simulation and experimental data.
© 2011 Optical Society of America
Instrumentation, Measurement, and Metrology
Original Manuscript: March 31, 2011
Revised Manuscript: July 5, 2011
Manuscript Accepted: July 19, 2011
Published: September 5, 2011
Yuanlong Fan, Yanguang Yu, Jiangtao Xi, and Joe F. Chicharo, "Improving the measurement performance for a self-mixing interferometry-based displacement sensing system," Appl. Opt. 50, 5064-5072 (2011)