Improved BER monitoring based on amplitude histogram and multi-Gaussian curve fitting

We present an improved multi-Gaussian curve-fitting method for monitoring bit error rate (BER) of optical channels that suffer from various kinds of impairments including ASE noise, in-band crosstalk, dispersion, self-phase and cross-phase modulations, and four-wave mixing. The new method is more flexible and computationally efficient, as compared with our previously proposed method. Computer simulations using commercial software are carried out to verify the effectiveness of the new method. The results show that the new method can achieve better accuracy in estimating BER over the conventional single-Gaussian approximation method, especially when the signal is severely distorted.