Dispersion Compensating Fiber, often abbreviated DCF, is a type of specialty optical fiber that is designed and constructed to exhibit negative chromatic dispersion characteristics over a specific wavelength range. What is Chromatic Dispersion? Chromatic Dispersion, refers to the phenomenon where different wavelengths (colors) of light travel at different velocities when transmitted through an optical fiber. In plain terms, it helps correct pulse broadening that builds up as light travels through fiber, especially in long-distance and dense wavelength-division multiplexing. Double-clad fiber (DCF) is a class of optical fiber with a structure consisting of three layers of optical material instead of the usual two. The inner-most layer is called the core. DCF techniques increase the total losses non-linear effects and costs of.