Mitigation of Optical Multipath Interference Algorithms in IM-DD Transmission System

This paper aimed to propose two algo-rithms,DA-M and RF-M,of reducing the impact of multipath interference(MPI)on intensity modula-tion direct detection(IM-DD)systems,particularly for four-level pulse amplitude modulation(PAM4)sys-tems.DA-M reduced the fluctuation by averaging the signal in blocks,RF-M estimated MPI by subtracting the decision value of the corresponding block from the mean value of a signal block,and then generated interference-reduced samples by subtracting the inter-ference signal from the product of the corresponding MPI estimate and then weighting factor.This paper firstly proposed to separate the signal before decision-making into multiple blocks,which significantly re-duced the complexity of DA-M and RF-M.Simulation results showed that the MPI noise of 28 GBaud IM-DD system under the linewidths of 1e5 Hz,1e6 Hz and 10e6 Hz can be effectively alleviated.