Trace Back Method of the Distributed Noise in Optical Transmission Systems

Noise is an inevitable phenomenon in optical data transmission systems, significantly impacting data quality. While noise has been a disturbance that researchers have made substantial efforts to mitigate, at the same time, it is a rich source of information about the underlying system. By comprehending the noise characteristics, we can deepen our understanding of the entire system including the topologies, performances, and even dynamics. Nonetheless, a challenge persists because the only noise we encounter is the cumulative one at the receiver, making it impossible to decompose the noise contributions by their source locations without specialized physical devices in the middle of the transmission link. This letter aims to shift the perspective on noise by exploring the potential insights gained through the analysis of noise inherently embedded in signals. We propose an innovative approach that leverages the received noise to trace back distributed link noise, eliminating the need of optical monitoring devices. By regenerating local nonlinear distortions using the received signal and employing correlation-based methods, we experimentally demonstrate the local noise detection and generalized optical signal-to-noise ratio estimation with commercial transceivers.