Bit error rate evaluation of a dual-filter heterodyne FSK optical system

The frequency separation between the two channels of a dual-filter heterodyne FSK optical system is a very important parameter to evaluate in the presence of laser phase noise. In this work the impairment due to the crosstalk interference between the two transmitted tones of a weakly coherent FSK optical system is investigated. In order to make accurate computations, the method of moments seems to be the most suitable: to this aim, in this work an algorithm for the moments evaluation is proposed. The numerical results are then compared with a Monte Carlo simulation approach