Analysis of a modified adaptive least mean square frequency-domain algorithm for equalization in polarization division multiplexed-mode division multiplexed fiber transmission

Mode division multiplexed(MDM) in few mode fibers has gained attraction due to its potential to achieve ultrahigh capacity beyond the nonlinear Shannon limit of the single mode fiber. However, it cannot be ignored that the effect of crosstalk, mode coupling and differential mode group delay on optical signals exists in transmission and equalizing these impairments are required in the digital signal processing(DSP). In this paper, a modified frequency domain least mean square(LMS) algorithm as the adaptive algorithm is proposed for the digital dispersion equalizer of polarization multiplexed few mode fiber MDM coherent single-carrier system. The simulation results show that the modified algorithm can improve the clarity of constellation and get better equalization performance comparing to the traditional algorithm.