Intensity modulation of orthogonally polarized laser with two weak light reinjection beams of the bifurcated sub-cavity

Abstract

This paper proposes a specially designed laser cavity with two reinjected beams to achieve coupled self-mixing interference. Based on the orthogonally polarized laser, a wave plate is employed to construct the bifurcated sub-cavity, and the oscillating laser mode splits into two. Under the domination of the sub-cavity, both the intensity and frequency of the orthogonally polarized beams exhibit near-sinusoidal modulation with a certain phase difference. The modulated intensity also has a long period envelope if the sub-cavity is tuned with pitch angle. Thus, it has potential to acquire the extension and bending displacement of such key components in a space-borne instrument.