Modified split-step fourier method for compensation of nonlinear fibre impairments

In this paper, we investigate a modified split-step Fourier method to enable computationally-efficient digital nonlinearity compensation for a coherently-detected 112 Gb/s polarization multiplexed quadrature phase shifted keying transmission over a 1,600 km link (20×80 km) with no inline compensation. We report up to 80% reduction in required stages to perform nonlinear compensation, in comparison to the conventional back-propagation algorithm. This method takes into account the correlation between adjacent symbols at a given instant using a weighted-average approach to enable practical digital nonlinearity compensation.