Optimized Backward Pumping Design for a 6-Mode Distributed Raman Amplifier for SDM Systems

We present the first optimized design and characterization of a six-mode distributed Raman amplifier (6M-DRA) for next-generation optical communication systems using space-division multiplexing (SDM) based on few-mode fibers (FMF). A genetic algorithm optimizes the pumping profile to minimize gain ripple and differential modal gain (DMG). Numerical results show an average on-off gain of 9.5 dB over 70 km, gain ripple below 1 dB, DMG under 2.10 dB, effective noise figure under 1.42 dB, optical signal-to-noise ratio larger than 29.5 dB, and pump efficiency of 9.30 dB/W, demonstrating its potential as an effective amplification solution for future SDM-FMF optical networks.