Measurement of birefringence dispersion in optical fiber using a method of white-light spectral interferometry

A white-light spectral interferometric method is used to measure directly the dispersion of the group modal birefringences for LP/sub 01/ and LP/sub 11/ spatial modes in elliptical-core fiber over a wide wavelength range. We employ a low-resolution spectrometer at the output of a tandem configuration of a Michelson interferometer and an optical fiber under test to record the spectral interference fringes resolved only in the vicinity of the so-called equalization wavelength. The spectral dependences of the group modal birefringences for LP/sub 01/ and LP/sub 11/ modes are measured directly by determining the equalization wavelength as a function of the path difference in the interferometer. Moreover, we showed that the spectral dependences of the phase modal birefringences for LP/sub 01/ and LP/sub 11/ modes can be determined by applying a polynomial approximation of the measurement results.