Achieving OPD super-resolution of the fiber-optic white light interferometer

A numerical method of processing data obtained by the fiber-optic white light interferometer to achieve Optical path difference (OPD) super-resolution is presented. It is well known that the resolution of interference signal depends on the coherence length of light source. Signal will be overlapped when the OPD is less than the coherence length. The area variation caused by overlapped is related to the OPD. The relationship between OPD and the size of signal area to be measured are given. The experiment results demonstrate the possibility of obtaining OPD with a resolution exceeding the coherence length of light source by 3 times. We believe this paper is benefit to absolute measurement of distance.