Abstract

Four-wave mixing (FWM) is a nonlinear process which is widely proposed to become the technique to be employed for all-optical wavelength conversion, because of its transparency to modulation format and bit rate, and its high efficiency. Transparency to modulation format is becoming increasingly important as the demand for capacity is pushing the optical communications industry towards the use of advanced modulation formats [1]. When FWM is used for all-optical wavelength conversion, it is important to understand the change in signal quality, from the signal (probe) to the converted wavelength (conjugate). In advanced modulation formats where information is encoded onto both the phase and amplitude of the optical carrier, the phase noise is a determining factor that influences the system performance as indicated by the bit error rate (BER). It has been shown that when two frequencies (ω_Pump and ω_Probe) undergo FWM in a nonlinear medium to generate a new frequency (conjugate, ω_Stokes at the lower frequency and ω_anti-Stokes at the higher frequency), the phase noise relationship is given by [2]

© 2013 IEEE