A Self-Mixing Laser Diode for Micro-Displacement Measurement

Authors

Han Wang, University of WollongongFollow
Yanguang Yu, University of WollongongFollow
Jiangtao Xi, University of WollongongFollow
Qinghua Guo, University of WollongongFollow
Jun Tong, University of WollongongFollow

RIS ID

133614

Publication Details

H. Wang, Y. Yu, J. Xi, Q. Guo & J. Tong, "A Self-Mixing Laser Diode for Micro-Displacement Measurement," in IFCS 2018 - IEEE International Frequency Control Symposium, 2018, pp. 1-4.

Abstract

A laser diode with the laser intensity and optical frequency altered by external optical feedback is often called as a self-mixing laser diode (SMLD). It can be used as a sensor for measuring various geometric parameters. This paper presents an SMLD design for micro-displacement measurement. The laser diode (LD) is modulated by the injection current in a form of triangular waveform and installed on a mechanic scanning device. The target to be tested and the SMLD forms the external cavity. The light reflected by the target contains the distance/displacement information. The information is carried within the laser intensity and can be pickup by a photo diode (PD) packaged in the rear of the SMLD. We call this laser intensity as self-mixing interferometric (SMI) signal. A new algorithm is developed to retrieve the micro-displacement from the SMI signal. Simulation results show that the proposed design is able to accomplish the measurement of displacement under weak feedback with high resolution and great accuracy.