Dispersion-shifted fiber (DSF) is a type of optical fiber made to optimize both low dispersion and low attenuation.
Dispersion Shifted Fiber is a type of single-mode optical fiber with a core-clad index profile tailored to shift the zero-dispersion wavelength from the natural 1300 nm in silica-glass fibers to the minimum-loss window at 1550 nm.
The group velocity or intramodal dispersion which dominates in single-mode fibers includes both material and waveguide dispersion.
However, when used in wavelength division multiplexing systems, dispersion-shifted fibers can suffer from four-wave mixing which causes intermodulation of the independent signals.
As a result, nonzero dispersion shifted fiber is often used.