We report a novel technique in which by combining the output from two multimode laser diodes a synthesized source with an extremely short coherence length is produced for use in white-light interferometric sensingsystems. Experimentally and theoretically it is demonstrated that, by summing the autocorrelation function of two multimode laser diodes with a wavelength difference of 108nm, a synthesized source with an equivalentcoherence length of ～4μm is generated, greatly reducing the signal-to-noise ratio required to identify the centralfringe position.