Experimental demonstration of visualized multi-core fiber coupling alignment system for inter-core cross talk measurement

Transmitting signals independently over each core of a multi-core fiber (MCF) is a candidate technology to cope with the growing demand for communication capacity. However, precise coupling alignment of input light beams and corresponding fiber cores is needed in such communication systems. Here we propose and experimentally demonstrate a novel, to the best of our knowledge, scheme for visualized MCF coupling alignment and inter-core cross talk measurement. The inter-core cross talk matrix of a bent 20-m 5-core fiber is measured in the experiment to show the efficiency of this scheme. Once the setup is established and fixed, the coupled MCF can be replaced at will. Due to the flexibility and simplicity of this scheme, it may possess potential value in MCF-based sensing and optical communication applications. (C) 2022 Optica Publishing Group