Comprehensive investigation of combining efficiency with a misaligned coherent fiber-optics-array collimator

Abstract

We propose a compact arrangement in a limited space for coherent beam combination, which is convenient to expand to the large-number channels. The presented arrangement for expanding combining channels utilizes the coherent fiber-optics-array collimator (CFAC), which employs a single unitary collimating lens to collimate the array beams, and a prism to adjust the tilt errors to ensure the array beams are projected parallel in a single aperture. We comprehensively investigate the influence of some perturbative errors on coherent combining efficiency with the seven-beam CFAC system. We have theoretically analyzed each type of error tolerance (80% of ideal combining efficiency) in this manuscript. Simulation results show that the errors introduced by edge beams cause the far-field beams to experience destructive interference, constructive interference and separation from the main lobe. The tolerance of the radial error, tangential error, defocus error and angular error of the prism are 0.015%, 0.16 mrad, 0.09% and 0.017%, respectively.

Optical Coupling Efficiency of a Coupler with Double-Combined Collimating Lenses and Thermally Expanded Core Fibers

“…An increasing amount of academics are using ZEMAX software to simulate couplers, reducing the cost of research. In 2019, Mingqian Zhang et al [14] proposed a coherent fiber array coupler to extend more channels and implemented the simulation with ZEMAX. However, imaging of a single lens has wide aberrations and is prone to divergence.…”