The frequency spectrum of a phase-modulated interferometer illuminated by a Gaussian source

A detailed theoretical analysis with numerical calculations was conducted to study the frequency spectrum resulting from the application of a sinusoidal phase modulation to a two-beam interferometer illuminated by a low-coherence source with a Gaussian spectral profile. Results of these calculations show behavior of the frequency components which was unexpected from earlier derivations of the frequency spectrum. The results of the calculations have been experimentally confirmed using an all-fiber interferometer illuminated by a source with a Gaussian spectral profile. The results will be useful for the signal processing of tandem interferometers for ''white light'' interferometry in the field of optical sensing.