Twin-core sunflower-type photonic quasicrystal fibers incorporated gold, silver, and copper microwire: an ultrashort and broad bandwidth polarization splitter

Polarization splitters are beneficial in the field of passive optical devices which are principally used in the coherent optical communication systems. An ideal polarization splitter must possess an efficient coupling with significant optical bandwidth. Hence, we proposed a novel metal-filled polarization splitter based on twin-core sunflower-type photonic quasicrystal fiber (PQF). The characteristics of the proposed splitter such as coupling length, extinction ratio, and available optical bandwidth were investigated by using the commercially available software, COMSOL Multiphysics. These aforementioned characteristics were determined by optimizing the geometrical parameters of proposed PQF—first by using gold-filled PQF (AuPQF). With optimized geometrical parameters, the splitter achieved an ultra-short coupling length of 132 µm and an ultra-broad bandwidth of 301 nm (wavelength range 1.36–1.68 µm) with an extinction ratio below than − 20 dB which comprised E + S+C + L+U band. Secondly, a comparative study to use silver- and copper-filled PQF (AgPQF and CuPQF) was explored. Both AgPQF and CuPQF retained a short length with adequate bandwidth and a significant extinction ratio below than − 20 dB. The AgPQF has a coupling length of 137 µm with a bandwidth of 136 nm which operated at 1.44 µm wavelength, while CuPQF with 134 µm lengths with a bandwidth of 149 nm and operated at 1.50 µm wavelengths.