In a single-mode optical fiber, the Wavelength or wavelengths at which material Dispersion and Waveguide dispersion cancel one another.

Note: In all silica-based optical fibers, minimum Material Dispersion occurs naturally at a wavelength of approximately 1.3 m. Single-mode fibers may be made of silica-based glasses containing dopants that shift the material-dispersion wavelength, and thus, the zero-dispersion wavelength, toward the minimum-loss Window at approximately 1.55 m. The engineering tradeoff is a slight increase in the minimum Attenuation coefficient.

2. Loosely, in a Multimode optical fiber, the wavelength at which material dispersion is minimum, i.e. , essentially zero. Synonym minimum-dispersion wavelength .