We present an optimized technique to generate frequency combs by four-wave mixing in highly nonlinear low-dispersion fibers. Three-pumps with unequally spaced frequencies (separation of 100 and 200 GHz) were used. The pumps were located relatively close to the zero-dispersion wavelength of the fiber. Using this three-pump technique we obtained a total of 275 FWM products experimentally, with a 100 GHz spacing and a spanning of over 220 nm. © 2009 Elsevier B.V. All rights reserved.