A novel square shaped air hole based photonic crystal fiber (PCF) is proposed with three symmetrical rectangular slots in the core region. A highly nonlinear material Gallium phosphide (GaP) is doped in the middle rectangular slot to achieve high nonlinearity and birefringence as well. Finite element method (FEM) is used for numerical investigation of the structure. Different optical parameters of the proposed PCF are calculated by varying its geometrical parameters. The optical parameters are optimized for the core pitch (${\text{Λ}}_C)$ value between the rectangular slots as 0.18 μm. From simulation results, it can be concluded that an ultra-high nonlinear coefficient and birefringence values of 0.645 × 10⁵ W⁻¹ km⁻¹ and 0.385 are achieved along with very low confinement loss and effective area of 2.10 × 10^-08 dB/m and 4.18 × 10⁻¹³ m², respectively at the centre of communication wavelength 1.55 μm. The core power fraction (CPF) is also found high as 98.056195% with extremely low effective material loss (EML) of 0.018 cm^-1. Moreover, scattering loss, beat length, numerical aperture (NA), V-parameter and spot size have also been calculated. Therefore, the proposed PCF can be effectively used in single mode polarization splitter, polarization maintaining fiber, solitons generator, four wave mixer, optical signal processing, bio-medical imaging and also in sensing applications.

提出了一种新颖的基于正方形气孔的光子晶体光纤（PCF），在芯区具有三个对称的矩形槽。高度非线性的材料磷化镓（GaP）掺杂在中间的矩形槽中，以实现高度的非线性和双折射。有限元方法（FEM）用于结构的数值研究。通过改变其几何参数来计算所提出的PCF的不同光学参数。光学参数针对核心间距进行了优化（${\text{Λ}}_C）$矩形槽之间的数值为0.18μm。从仿真结果可以得出结论，获得了超高的非线性系数和0.645×10 ⁵ W ^-1 km ^-1和0.385的双折射值，以及非常低的限制损耗和有效面积2.10×10 ^-08 dB /在通信波长1.55μm的中心处分别为m和4.18×10 ^-13 m ²。还发现核心功率分数（CPF）高达98.056195％，而有效材料损耗（EML）仅为0.018 cm ^-1，非常低。此外，还计算了散射损耗，拍长，数值孔径（NA），V参数和光斑大小。因此，所提出的PCF可以有效地用于单模偏振分束器，保偏光纤，孤子发生器，四波混频器，光信号处理，生物医学成像以及传感应用中。