Fiber nonlinear impact on hybrid ultra-dense WDM based optical networks

This paper addresses the system impact of fiber nonlinear crosstalk on ultra-dense hybrid coherent optical WDM optical network. Using Volterra theory, the transmission performance in terms of error vector analysis is evaluated and different contributions of nonlinear crosstalk are calculated. Firstly Volterra theory is validated against split-step Fourier simulations considering both intensity-modulated direct-detected channels and quadrature phase-shift keying (QPSK) channels co-propagating into the fiber at a very high density: 32 × 1.25 Gbaud spaced at 3 GHz. Then, the transmission performance of QPSK channels employing coherent detection is evaluated under different network topologies.