Ultra high birefringence and lower beat length for square shape PCF: Analysis effect on rotation angle and eccentricity

In this article, a circular air hole organized in a square manner cladding with porous core using elliptical holes index-guiding photonic crystal fiber (IG-PCF) has been proposed and numerically examined. The numerical study is obtained by using finite element method (FEM) inclusion with an electromagnetic absorption boundary perfectly matched layer (PML). Investigation process runs over a broader wavelength range near IR region from 1.20 µm to 1.80 µm for evaluating modal properties of proposed square shaped PCF. S-PCF expresses higher birefringence (2.2 × 10−3), high nonlinearity (23.46 W−1 km−1) along with lower beat length (553.86 µm) at the pumping wavelength λ = 1.20 µm. Core holes angle orientation and eccentricity are tuned for gaining higher birefringence. Furthermore, beat length, Veff, spot size, beam divergence are inquired in details. Finally, this research is focused on birefringence and nonlinearity behaviors are highly affected by angle effect and eccentricity.