Three-channel passive phase locking laser on a ring cavity

Phase difference locked three-channel coherent lasers are of great importance in multi-channel lasers interferometry processing and imaging research. In this paper, a three-channel passive phase-locked laser based on a triangular ring resonant cavity was designed and experimentally verified. The final locking of the phase difference of the three beams under mutual injection operation was analyzed in detail from the theoretical model when the initial phase difference values were different. A three-channel mutually injected laser was built and used as the laser source to carry out a three-beam interference experiment, and a three-beam far-field interference pattern with a periodic regular hexagonal lattice structure was obtained. The experimental results showed that the laser source has high coherence and is easy to adjust the three-beam interference period. This study provides a novel approach, to the best of our knowledge, to developing new solid-state laser coherent laser sources.