Optimization of spin parameters for spun fibers having low polarization mode dispersion

摘要

Polarization mode dispersion (PMD) is a dispersive effect caused by the birefringence of the optical fiber. Spinning the fiber with periodic profiles during the drawing process from preform is known as a PMD-reducing process. In this paper, common spin parameters giving successful results in obtaining low PMD for three spin profiles, i.e. sinusoidal, amplitude modulation-suppressed carrier (AM-SC) and amplitude modulation-transmitted carrier (AM-TC), are searched and an optimization problem based on this research is defined. This optimization problem is solved by using Differential Evolution Algorithm (DEA) and common spin parameters suitable for all discussed spin profiles are obtained. For all spin profiles, optimum common spin parameters are found to be 8.81 turns/m for the spin amplitude and 3.69 m for the spin period. Numerical analysis performed with those optimum spin parameters show that in the short fiber regime the differential group delay (DGD) takes a value under 0.25 fs and the mean DGD value remains lower than 15 fs in long lengths of fiber. The obtained results show that PMD reduction with respect to unspun fibers can be achieved by using optimized spin profiles even in the case of random mode coupling.