A newly developed technique for directly measuring fiber dispersion in the frequency domain as a function of wavelength is described. A number of germanium‐ and boron‐doped fibers have been examined. The least dispersive borosilicate graded‐index fiber has a 1‐dB bandwidth of 1 GHz, after 1.07 km of propagation at &lgr;=908 nm. Frequency domain measurements were inverted into the time domain after assuming that the phase of a power transfer function could be calculated from its amplitude spectrum.