Evaluation of polarization mode coupling coefficient from measurement of polarization mode dispersion

Polarization mode coupling coefficient is evaluated from the measurement of polarization mode dispersion as a function of fiber length in a single-mode fiber having an elliptical-core with 10-percent ellipticity. The modal dispersion measurement are carried out by the improved spatial technique based on an optical heterodyne detection at the wavelengths of 0.85 and 1.3 μm. The coupling coefficients are evaluated from the measurements to be3.4 × 10⁻³and4.6 × 10⁻³m-1for modal-birefringence magnitudes of8 × 10⁻⁶and3 × 10⁻⁶, respectively. The coupling coefficients obtained from the dispersion measurement are coincident with those evaluated from the extinction-ratio measurements. In addition, dependence of the coupling coefficient on propagation constant difference between the two orthogonally polarized HE11modes is investigated based on Lorentzian power spectrum model.