OTDR trace distortion correction in Raman-amplified systems using transformer models

We present a Transformer model-based method for correcting optical time domain reflectometer (OTDR) trace distortions in Raman-amplified optical systems. Unlike prior approaches, the proposed model operates without requiring Raman pump power information or a reference trace, relying only on the distorted OTDR trace, fiber length, and pump wavelengths-parameters readily available in deployed networks. By predicting the accumulated stimulated Raman scattering (SRS) gain, the model effectively removes Raman-induced distortions in a single step, eliminating the need for additional curve fitting. Experimental results on a 180 km Raman-amplified span show that the model reduces mean squared error (MSE) by over an order of magnitude, restoring baseline trace features and connector losses with high fidelity. The method enhances robustness to Raman pump power-related uncertainties, simplifies the correction process, and enables scalable, in-service diagnostics for high-capacity fiber links.