Study on coherent coupling of multi-core PCFs

In this work, we used R-Soft software to simulate the coupling between multi-core photonic crystal fibers (PCFs) with different core diameters and distances. The simulation results show that the core distance within two wavelengths, different core diameters between the mode fields can be effectively coupled. The results are consistent with the evanescent wave propagation length of calculation. According to the designed structure based on the high temperature melting method, the multi-core PCF can be obtained by using two times technique of the optical fiber drawing tower. The core production of (2-, 7-, 19-core PCF) of coherent synthesis experiment, observed apparent interference fringes in the experiment, which shows that the mode fields of the multiple cores meet the coherent conditions. This article provides a theoretical basis and guidance to effectively achieve a coherent coupling for the further design and preparation of multi-core fibers (more than 19 cores).