Self-mixing interferometer: analysis of the output signals

Abstract

This paper presents the calculation of amplitude and relative phase of signals at the three outputs available in a self-mixing interferometer, i.e. the front output on the target side, the back output on the rear of the chip, and, for diode laser, the junction voltage output. Front and rear outputs are observed to be in phase for the He-Ne laser while they are in phase opposition in the diode laser. This discrepancy can now be explained theoretically. It will also be shown how the junction voltage output is always in phase opposition with respect to the rear output. Experimental measurements were carried out on two sources: a laser diode and a He-Ne laser, validating the calculations.