This work presents a three-pump technique for generating cascaded four-wave mixing spaced by only 0.8nm or 100 GHz, which is the standard separation between Dense- Wavelength Division Multiplexing channels. It consists of using very short optical fibers, few meters, and three closely pumps (100-200 GHz), but unequally spaced in frequency, and relatively close to the zero-dispersion wavelength of the fiber. It has obtained 275 FWM products locked to the 100 GHz standard telecommunications grid.