Design of High Nonlinear Photonic Crystal Fiber with Low Loss Spiral Structure

【Objective】As a potential important optical device, chalcogenide high nonlinear fiber has a wide application prospect in the mid-infrared region. In order to meet the requirements of optical signal processing and transmission in infrared region, a chalcogenide high nonlinear fiber is proposed to improve the efficiency and performance of optical signal processing in the infrared region.【Methods】Using the finite element method as a design and analysis tool, combined with the selection of highly nonlinear materials and the optimization of fiber structure parameters, the fiber design with efficient nonlinear effects in the mid-infrared region is realized. The confinement loss, dispersion and nonlinear coefficient of the highly nonlinear Photonic Crystal Fiber (PCF) with spiral structure of As₂Se₃ material in the wavelength range of 1~7 μm are analyzed and optimized.【Results】The results show that the confinement loss can be as low as 10^-8 orders of magnitude at the wavelength range of no more than 6.25 μm. It has dispersion flattening characteristics at the mid-infrared region range of 2~5 μm. There are multiple zero dispersion points in the range of 1~7 μm, and the nonlinear coefficient can be as high as 248 630 W^-1·km^-1.【Conclusion】The fiber can realize ultra-wideband low loss dispersion flatness and high nonlinearity in the mid-infrared region, and has potential application prospects in the field of mid-infrared optical communication and optical sensing.