Polarization-mode dispersion (PMD) is an optical effect that spreads or disperses an optical signal in single-mode fibers. In the case of a high data rate, long-length (>100 km) system, PMD can become a limiting factor for network spans when the effect of more traditional chromatic dispersion has. PMD occurs when light pulses of different polarizations travel at varying speeds through an optical fiber. Ideally, these pulses should move at the same speed, but small imperfections in the fiber's core and cladding cause them to spread over time, leading to overlap and interference between. Polarization Mode Dispersion (PMD) is a critical factor affecting the performance of high-speed optical communication systems. As data rates continue to soar, understanding and mitigating PMD becomes increasingly important. In digital multimode fiber systems, a light pulse separates into multiple spatial paths or modes.