Adaptive Frequency-Domain Equalization for Mode-Division Multiplexed Transmission

We propose single-carrier adaptive frequency-domain equalization (SC-FDE) for mode-division multiplexed transmission. A two-mode fiber long haul transmission system is simulated. The performances of both FDE and time-domain equalization (TDE) are verified and compared. The FDE approach reduces the computational complexity significantly compared to the TDE while maintaining the same performance. For a two-mode transmission of 2000 km, FDE decreases the complexity by a factor of as much as 77 compared with TDE at the expense of a large memory length of 2048 that may require higher hardware complexity. The dynamic response of the adaptive equalizer is simulated by using a mode scrambler. FDE achieves the same tracking speed as TDE