Mode-division multiplexing of signals and Raman pumps in low differential mode group delay multimode optical fiber

We numerically model and experimentally demonstrate the Raman-based amplification of optical signals in a mode-division multiplexed multimode optical fiber. We used mode multiplexers and demultiplexers using the multi-plane light conversion technology, and an 8km span of low-differential mode group delay specialty graded-index fiber supporting 15 modes. Inter-modal stimulated Raman scattering between signal and pump beams, coupled in distinct modes of the multimode optical fiber, permits to fully compensate for transmission fiber losses.