By combining self-mixing interferometer (SMI) and grating interferometer (GI), a self-mixing grating interferometer (SMGI) is proposed in this paper. Self-mixing interference occurs when light emitted from a laser diode is diffracted by the doublediffraction system and re-enters the laser active cavity, thus generating a modulation of both the amplitude and the frequency of the lasing field. Theoretical analysis and experimental observations show that the SMGI has the same phase sensitivity as that of the conventional GI and the direction of the phase movement can be obtained from inclination of the interference signal. Compared with the traditional SMI, the phase change of interference signal in SMGI is independent of laser wavelength, providing better immunity against environmental disturbances such as temperature, pressure, and humidity variation. Compared with the traditional GI, the SMGI provides a potential displacement sensor with directional discrimination and quite compact configuration.

Date Published: 28 August 2016
PDF: 5 pages
Proc. SPIE 9960, Interferometry XVIII, 996019 (28 August 2016); doi: 10.1117/12.2239519

Published in SPIE Proceedings Vol. 9960:
Interferometry XVIII
Katherine Creath; Jan Burke; Armando Albertazzi Gonçalves Jr., Editor(s)