Design of photonic crystal fiber with elliptical air-holes to achieve simultaneous high birefringence and nonlinearity**Project supported by the National Natural Science Foundation of China (Grant No. 61475029).

Abstract

A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high birefringence and nonlinearity at a wavelength of 1.55 μm. The full vector finite element method was adopted to investigate its characteristics, including birefringence, nonlinearity, and dispersion. The PCF exhibited a very high birefringence of 2.89×10−2 and very high nonlinear coefficient of 102.69 W−1⋅km−1. In particular, there were two zero-dispersion wavelengths (ZDWs) in the visible (X: 640–720 nm and Y: 730–760 nm) and near-infrared regions (X: 1050–1606 nm and Y: 850–1500 nm). The combination of high birefringence and nonlinearity allowed the PCF to maintain the polarization state and generate a broadband super continuum, with potential applications in nonlinear optics.