This paper proposes a novel hexagonal-shaped dual-core photonic crystal fiber (HX-PCF) for a wide telecom window. We test different optical parameters including birefringence (Bi), power fraction ($\eta \prime$), effective area (Aeff), numerical aperture (NA), nonlinear coefficient ($\gamma$), v-parameter, chromatic dispersion ($\beta 2$), transmittance) ($Tx$), and relative sensitivity ($Rs$) and loss profiles including effective material loss, confinement loss ($\alpha c$), scattering loss ($\alpha sc$), and bending loss ($\alpha bl$) compared with the most recent models. In addition, the finite element method is employed on wavelength-division multiplexing with 310,534 mesh elements over a wide telecom window wavelength range of 1500–3000 nm and porosity of 30–60%. The proposed HX-PCF displays outstanding performance for these parameters. The optimal key performance indicator profiles are 2.2 × 10−3, 99.79%, 1.69 × 10−11 m2, 0.99, 0.203 m−1, 10−9 dB/m, 18.5 × 10−3 dB/m, 10−8 dB/m, 9.1 × 1010 W−1 km−1, 185 ps/(nm.km), −240 dB, and 41.75%, respectively, for the corresponding optical parameters of Bi, $\eta \prime$, Aeff, NA, $\alpha EML$, $\alpha c$, $\alpha sc$, $\alpha bl$, $\gamma ,$$\beta 2$, $Tx$, and $Rs$. This fiber is more promising than any previous model, based on ultra-flattened dispersion, high nonlinearity, high NA, transmittance, and relative sensing, along with very low loss profiles. Moreover, it is shown to be a good candidate for telecommunication, optoelectronics, four-wave mixing, fiber loop mirroring, and other high-speed transmission media.