Silicon -embedded photonic crystal fiber for high birefringence and nonlinearity

In this study, we propose a hexagonal photonic crystal fiber (PCF) including an elliptical Si core for high nonlinearity and birefringence, simultaneously. The propagation properties are rigorously investigated by numerical full-vector analysis. The designed fiber provides high nonlinearity and birefringence for a wide range of wavelengths, from 1.25 to 2 μm, maintaining low propagation loss by virtue of a high nonlinear coefficient and large Si refractive index. The optimal values of nonlinearity and birefringence are 2 × 105 W−1 km−1 and 0.92, respectively. In addition, the proposed hexagonal PCF can be easily fabricated with a conventional draw technique compared with other PCFs composed of complex structures to achieve high nonlinearity. It also has a high fabrication tolerance for the rotational angle of the elliptical Si core. We believe that this type of the fiber could be applied to various efficient nonlinear applications. © 2020 Elsevier GmbH