Computation of bit error ratios for a dense WDM system using the noise covariance matrix and multicanonical Monte Carlo methods

We extend the noise covariance matrix method to dense wavelength-division-multiplexed (DWDM) systems in order to efficiently and accurately compute the probability density function of the received voltage in the central channel of a DWDM 10-Gb/s chirped return-to-zero transmission system with a channel spacing of 50 GHz and a transmission distance of 6120 km. The results agree with those that we obtain using a multicanonical Monte Carlo method, which mutually validates both methods.