Reducing multipath interference in quasi-single-mode transmission via distributed Raman amplification

Abstract

In this Letter, we show numerically and experimentally that multipath interference can be reduced significantly by distributed Raman amplification (DRA) in quasi-single-mode transmission using few-mode fibers, owing to the extra differential mode attenuation induced between the fundamental mode and higher-order modes. The experimental results show that the required number of equalization taps can be reduced by 1.6 times. Moreover, by carefully optimizing the intensity overlap between the LP01 and LP11 modes through structural adjustment of the two-mode fiber, a 3.5-times reduction in the required number of taps can be obtained.