Among various optical fiber distance sensing techniques, optical fiber sensors based on white-light Fabry-Perot interferometry offer the simplest configuration, the highest sensitivity, and the most precise distance measurement. Because a whitelight interferometric sensor can overcome the directional ambiguity problem encountered by the other interferometric techniques, it is especially attractive for applications where absolute distance measurement is desired. However, conventional two-fringe matching data demodulation technique can induce a half wavelength error to the distance measurement. In this paper, we present an improved fringe matching data interrogation technique that can overcome this problem. The data interrogation scheme consists of two steps: a rough estimation of the distance and the phase shift using the two fringe matching technique and a more precise estimation of the distance and the phase shift using the correctional terms derived from the fringe difference. Simulation results indicate that the algorithm can converge to the correct distance with sub-Armstrong accuracy over a large dynamic range.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.