Kilowatt-Level Narrow-Linewidth Cascaded Raman Fiber Laser Enabled by Stochastic Grating Feedback

We propose and experimentally validate a novel cascaded Raman fiber laser (CRFL) architecture featuring dual-grating cooperative feedback. Numerical modeling reveals the physical mechanism by which grating reflectivity fluctuations enable spectral redistribution and noise suppression through stochastic feedback effects. The experimental implementation demonstrates 1031W output at 1185 nm with 1.15 nm linewidth and 45 dB higher-order Stokes suppression, validating the theoretical predictions.