Abstract A photonic crystal fiber in square lattice architecture is numerically investigated and proposed for broadband dispersion compensation in optical transmission system. Simulation results reveal that it is possible to obtain an ultra-high negative dispersion of about −571.7 to −1889.7 (ps/nm.km) in the wavelength range of 1340 nm to 1640 nm. Experimentally it is demonstrated that the design fiber covers a high birefringence of order 4.74×10^‒3 at the wavelength of 1550 nm. Here, numerical investigation of guiding properties and geometrical properties of the proposed PCF are conducted using the finite element method (FEM) with perfectly match layers. Moreover, it is established more firmly that the proposed fiber successfully compensates the chromatic dispersion of standard single mode in entire band of interest. Our result is attractive due to successfully achieve ultra-high negative dispersion that is more promisor than the prior best results.