Fourier transform method to measure of the chromatic dispersion in an optical fiber

Abstract

The measurement of phase is important in multiple applications, such as in interferometry, radar applications, tomography, among others. As a particular application, phase extraction can be used to evaluate the chromatic dispersion coefficient in optical fibers. There are multiple setups that employ the phase of an interferometric signal to evaluate this coefficient. Usually in those systems the phase shift evaluation of the sine-like interferometric signal is performed measuring the shift of a single maximum. This means that only a few points in the interferogram are used and many other are wasted. In this work a Fourier Transform method to obtain interferogram phase shift to evaluate chromatic dispersion of an optical fiber is presented. Results of the dispersion coefficient of fiber with a length of hundreds of meters evaluated by using a Sagnac interferometer are shown.