Numerical modelling of far-field intensity patterns in coherent beam combining

Coherent Beam Combining (CBC) is one of the novel methods aiming to increase laser output power and intensity, especially in cases where applications require both high power and high beam quality. CBC offers a way of exceeding limitations of a single-fiber laser source, allowing for excellent scalability and high efficiency operation. Simulating and optimizing the intensity of the far-field is crucial when designing a CBC system. This paper focuses on a way of approaching numerical solution of the electric field intensity along the Rayleigh range of multiple Gaussian beams coherently combined over large distances. It aims to circumvent the restrictions of computational capacity faced by most numerical methods when solving for the optical field propagation over large geometries by combining ray and wave optics approach. Output intensity fields for coherent combination of 6, 12, and 20 channels operating at a wavelength of 1550 nm are presented, using a Cassegrain type telescope as beam combiner. Influence of design parameters and near field arrangement is examined and results are compared with previously reported experimental values.