Evaluating SOA nonlinearity effects by high-order susceptibility on constant envelope signals in WDM systems

摘要

Nonlinearity effects, arising within a semiconductorudoptical amplifier, have been deeply investigated with particularudinterest for exploiting them in wavelength conversion. This applicationudshrinks the research area to a precise scenario: a strongudpump signal travels through the active medium simultaneouslyudwith a modulated signal to be converted. In this case it is possibleudto neglect the spectral distribution of the optical power and phaseudrelationship between propagating signals. SOAs have been alsoudstudied as line amplifiers for WDM phase modulated signals.udAim of this paper is to extend the propagation model in a SOA,udin order to simulate nonlinearities occurring in the amplificationudof a WDM comb signal evaluating FWM on constant envelopeudmodulation schemes (DPSK). This can be carried out thanksudto an enanched analytical model based on the optical field andudmedium interaction, overcoming the wide-used Rate Equationudapproach, which is based on the overall photons density.