Non-zero dispersion-shifted fiber (NZDSF), specified in ITU-T G.655, is a type of

single-mode optical fiber In fiber-optic communication, a single-mode optical fiber, also known as fundamental- or mono-mode, is an optical fiber designed to carry only a single mode (electromagnetism), mode of light - the transverse mode. Modes are the possible solutio ...

which was designed to overcome the problems of dispersion-shifted fiber. NZDSF is available in two primary flavours: NZD+ and NZD-, which differ in their zero-dispersion wavelengths. These are typically around 1510 nm and 1580 nm, respectively. Because the zero-dispersion point of NZDSF is outside of the normal communications window,

four-wave mixing Four-wave mixing (FWM) is an intermodulation phenomenon in nonlinear optics, whereby interactions between two or three wavelengths produce two or one new wavelengths. It is similar to the third-order intercept point in electrical systems. Four-wave ...

and other non-linear effects are minimized. Other types of NZDSF include which has a reduced slope in its change of dispersion and large core NZDSF which further reduces residual non-linear distortion under high launch power. Some long-haul fiber paths will alternate NZD+ and NZD- segments to provide self-dispersion compensation with uniformly low dispersion across the minimum-loss window at 1550 nm.

References

Optical fiber {{Optics-stub