Dispersed fringe sensor (DFS) is a phasing sensor based on principle of white-light double-slit interferometry. We theoretically and experimentally analyze characteristics of capture range of the DFS, propose mathematic description of capture range of the DFS and put forward a simple but practical strategy to maximize capture range of the DFS in our project. Finally, the experimental demonstration verifies validities of the mathematic description of capture range of the DFS and the strategy for optimizing...