Numerical investigation of low level OSNR estimation based on gaussian fitting and non-linear least squares on AAH in noisy optical communication links

An extended digital estimation approach of optical signal to noise ratio (OSNR) based on statistical analysis of asynchronous amplitude histograms (AAH) of the received optical signal is presented and numerically investigated. Accurate OSNR estimation on highly noisy optical transmission link is achieved. Furthermore, the proposed OSNR estimation approach may be digitally adjusted to any Cartesian modulation format such as multilevel phase shift keying and quadrature amplitude modulated optical signals without degrading estimation accuracy. The OSNR estimation methodology is based on kernel density estimation with Gaussian kernels and non-linear least-squares regression (NLLS). Heuristic searches are no longer needed and the process becomes more reliable and robust. Reported results show accurate OSNR estimation with less than 15% error estimation on the simulated OSNR value for different signal modulation formats, exhibiting a more confident estimation system, with comparable results among formats because of the statistical nature histogram instead of the regular counting bins histogram.