Phase-locking in fiber laser arrays

Evanescently coupled fiber laser arrays are investigated as a powerful and compact all-solid-state source of coherent radiation for high-power applications. The micro-structured multiple-core design provides a novel power scaling technique and overcomes traditional restrictions of single-core fiber lasers. The increased bending loss stability and the mode selectivity of the trigonal array was proven for the first time on the basis of a rigorous vector coupled-mode theory. Phase-locking in the in-phase supermode is predicted as a combined effect of the strong evanescent coupling and the bending loss mode selection. In its simplest configuration with three cores in a trigonal arrangement a 2.79 fold power scaling is expected with a almost diffraction limited beam quality.