In quasi pattern, photonic crystal fiber (PCF) with Ge₂₀Sb₁₅Se₆₅ rectangular core is modeled. In this article, few optical properties of PCFs like power fraction, nonlinearity, effective mode area, birefringence, beat length, waveguide dispersion are obtained using finite element method (FEM). The proposed structure demonstrates significant effect on few optical properties for two polarization modes. It produces a high nonlinearity of 6.161 × 10³ W⁻¹Km⁻¹and birefringence of 1.46 × 10⁻¹ inside infrared region (IR). This proposed structure may play a vital role in multitasking applications.