Low complexity digital back propagation method using phase linear approximation for nonlinear distortion compensation for long haul transmission systems

Abstract

We propose a novel nonlinear distortion compensation technique using linear phase transition approximation for long haul optical communication system. Self-phase modulation (SPM) for phase change, and amplified spontaneous emission (ASE) from erbium-doped fiber amplifier (EDFA) are taken into consideration in simulation. It is confirmed that phase of 28Gbaud return to zero - quadrature phase shift keying (RZ-QPSK) signals compensated with split-step Fourier methods (SSFM) change almost linearly. They can be estimated using linear approximation with only two points of any span for low computational complexity. The performance of this technique is evaluated by bit error rate (BER) with numerical analysis. The achieved reduction of computational amount is 70.0% when transmission distance is 2500km and input power is 0dBm at a FEC limit of BER < 10⁻³.