In transmission with Dense Wavelength Division Multiplexing( DWDM), nonlinear dispersions lead to interference and four-wave mixing between the light signals. For this reason, DWDM systems must use monomode fibers whose nonlinear dispersion range lies outside the wavelengths used.
The NZDSF fiber (Non Zero Dispersion Shifted Fiber), which is specified in ITU-T Recommendation G.655, is such a fiber. According to the ITU-T standard, NZDSF fibers have a minimum dispersion at a wavelength of 1,550 nm, an attenuation of 0.25 dB/km at 1,550 nm and a typical dispersion of 4.5 ps/nm relative to one kilometer. The NZDSF fiber has been optimized for transmission rates of 10 Gbit/s and 40 Gbit/s, can operate in C-band and L-band, and can bridge distances of up to 100 km without an amplifier. Peak values of 10 Tbit/s over 100 km were already achieved in 2001.