Tapered Multicore Fiber for High-Power Laser Amplifiers

Abstract

The problem of coherent amplification of the out-of-phase mode in tapered multicore fibers with cores arranged in a ring and in a square lattice is studied theoretically. The stability of out-of-phase field distributions with respect to both inhomogeneities of the refractive index and the initial wave field distribution is demonstrated in numerical modeling. Coherent combining of radiation into a single beam with good quality and efficiency of about 80% for ring cores arrangement and more than 90% for square cores arrangement is possible. Achievement of 55 MW of total power at the output of a fiber with 11 × 11 cores is numerically demonstrated.