Coupling characteristics of high birefringence dual-core As2S3 rectangular lattice photonic crystal fiber

A type of As2S3 chalcogenide glass mid-infrared dual-core photonic crystal fiber has been proposed. The dual-core photonic crystal fiber (PCF) consists of two asymmetric cores. The high polarization property and the coupling characteristics have been studied by using the finite element method and mode coupling theory. Numerical results show that the birefringence at wavelength lambda = 10 mu m is up to 0.01386 and the coupling length can reach wavelength lambda = 5 mu m, 261 mu m and 271.44 mu m for x-polarized mode and y-polarized mode, respectively. It demonstrates that a 6.786-mm-long fiber can exhibit an extinction ratio of better than -10 dB and a bandwidth of 180 nm.