Measurements of birefringence dispersion and intermodal dispersion in a two-mode elliptical-core optical fibre using an interferometric method

摘要

A spectral-domain white-fight interferometric technique is used in measurement of the dispersion of the group modal birefringences for the LP01 and LP11 spatial modes in an elliptical-core optical fibre. The dispersion of the intermodal group optical path differences (OPD) between the LP01 and LP11 modes of each polarization is also measured. The technique, which employs a low-resolution spectrometer at the output of a tandem configuration of a Michelson interferometer and a two-mode optical fibre, utilizes the resolving of so-called equalization wavelengths at which the OPD in the interferometer is the same as the differential or intermodal group OPD. The measured data are fitted to polynomials to obtain the dispersion of both the phase modal birefringences and the differences between propagation constants of two LP modes. The results obtained are compared with the results of an adequate theoretical analysis.