Zero-dispersion slope

Zero-dispersion slope: In a single-mode optical fiber, the rate of change of dispersion, with respect to wavelength, at the fiber's zero-dispersion wavelength.

Note 1: In silica-based optical fibers, the zero-dispersion wavelength occurs at approximately 1.3 μm, but this wavelength may be shifted toward the minimum-loss window by the addition of dopants to the fiber material during manufacture.

Note 2: Doubly and quadruply clad single-mode fibers have two zero-dispersion points, and thus two zero-dispersion slopes.

Source: from Federal Standard 1037C