Fabrication of a low insertion loss and high productivity FI/FO device based on the different core couple method and tapered corrosion method

Two innovative methods, the different core couple (D-C) method and the tapered corrosion (T-C) method, are proposed to improve traditional fiber bundle corrosion techniques for fabricating fan-in/fan-out (FI/FO) devices. The D-C method utilizes fibers with varying core diameters to facilitate light transmission from smaller to larger diameters, enhancing the fault tolerance of a fiber core structure on the end-face of FI/FO devices and minimizing optical signal leakage at the multiplexer joint, thereby reducing insertion loss (IL). Taper-cut and fusion-splicing techniques ensure the compatibility of the device with standard optical communication systems. The T-C method presents the idea of tapered corrosion fibers applied to FI/FO device fabrication, significantly enhancing production efficiency through a simple, repeatable, and cost-effective process. The above two methods were used to fabricate the corresponding FI/FO device for four-core single-mode fibers (4C-MCF), which are employed for signal multiplexing and demultiplexing. The device has a low average IL value of less than 0.5 dB, with cross talk lower than -60 dB, meeting the requirements for fiber-optic communication. This work provides two techniques for the fabrication of FI/FO device in multi-core fiber (MCF) communication systems, which can be expected to promote the innovation and development of space division multiplexing (SDM) technology.