Multi-plane light conversion (MPLC) is a versatile technique that enables arbitrary manipulation of optical fields, and is numerically investigated as a novel avenue for coherent beam combining (CBC) applications. The optical parameters have been investigated to guide the MPLC design, indicating that the number of phase planes and plane spacing serve as pivotal factors. The channel scalability is simulated, revealing that the plane spacing should be increased in a larger array to maintain high performance under a few-plane limit. CBC of up to 1027 lasers has been numerically demonstrated with near-diffraction-limited beam quality (M2 of 1.16 and combining efficiency close to 100%) with only seven phase plates. Beam steering is investigated, revealing that steering capability is related to both the number of multiplexed modes in MPLC and their mode fidelities, and the main-lobe power ratio of 87.1% at one divergence angle is achieved in a 10-mode MPLC with five phase plates.
