What are the types of dispersion in optical fiber and how do they affect transmission?

Dispersion causes pulse broadening, limiting fiber bandwidth. Types: Modal dispersion (multimode fiber only, different modes travel different paths), Chromatic dispersion (wavelength-dependent velocity, both material and waveguide components), and Polarization Mode Dispersion (PMD, random birefringence in fiber). Mitigation: Single-mode fiber eliminates modal dispersion, Dispersion-shifted fiber or compensation modules address chromatic dispersion, and PMD compensation for very high rates. Dispersion limits bandwidth-distance product and affects system reach at high data rates.