The technique of high power laser beam combination using liquid crystal spatial light modulator

Abstract

Based on the phase modulation characteristics of optically addressed liquid crystal spatial light modulator (OA-LC-SLM) which is realized by controlling the power of addressing light, a physical model of coherent beam combination fiber laser using a bunch of fibers and a device of OA-LC-SLM is established on the theory of diffraction optics and liquid crystal birefringence effect. On the basis of this model, the properties of given scheme of coherent beam combination fiber laser are investigated including main lobe distribution and ability of phase modulation. Meanwhile, the plot functions of phase modulation versus the optical power of addressing light are obtained on different given driving voltage conditions and fiber alignment parameters such as core diameter and filling factor. After the numerical simulation, it shows that, this coherent beam combination fiber laser using OA-LC-SLM demonstrates an ability of coherent beam combination on the far field. With the increase of core diameter, the combination efficiency is improved better, and the divergence angle decreases narrower.