Experimental demonstration of XPM compensation for WDM fibre transmission

Introduction: Coherent detection combined with digital signal processing is emerging as one of the most promising techniques for longhaul fibre transmission. One of the benefits of coherent detection is that the complete information of the optical field including amplitude and phase can be obtained, which enables the compensation of dispersion and nonlinearity by digital backward propagation [1, 2]. Digital backward propagation (DBP) can be implemented by solving the total-field nonlinear Schrödinger equation (NLSE) or the coupled NLSEs. By solving the coupled NLSEs, cross-phase modulation (XPM) can be compensated while neglecting the effects of four-wave mixing (FWM). In comparison with XPM+ FWM compensation by solving the total-field NLSE, XPM compensation via coupled NLSEs requires a smaller computational load [3]. Moreover, XPM compensation does not need phase-locked local oscillators to reconstruct the total optical field. Distributed nonlinearity and dispersion compensation by solving the total-field NLSE has been experimentally demonstrated [4]. In this Letter, we experimentally demonstrate XPM compensation via coupled NLSEs for WDM transmission.