Fei Zhu

Nonlinear Phase Noise Mitigation With Soft-Differential Decoding and Nonredundant Error Correction for Hybrid 10G/100G Transmission

We report experimental results of 112-Gb/s po larization-division-multiplexed return-to-zero quaternary phase-shift-keying (PDM-RZ-QPSK) transmission over dis persion-managed 1200-km links embedded between 10.7-GBaud on-off keying nonreturn-to-zero (OOK-NRZ) neighbors. Taking into account implementation constraints for equalization and synchronization of the digital signal processing (DSP) by means of processing delay and parallelization, the performances without differential decoding, with hard-differential decoding, and with soft-differential decoding are evaluated. The combination of soft-differential decoding with nonredundant error correction is identified to provide the best mitigation of cross-phase modulation (XPM)-induced nonlinear phase noise.

MMSE-Based Optimization of Perturbation Coefficients Quantization for Fiber Nonlinearity Mitigation

In perturbation-based digital fiber nonlinearity mitigation methods, such as pre-distortion and post-equalization, quantization of perturbation coefficients is employed to reduce the computational and implementation complexity. However, quantization introduces errors, which results in performance penalties. By analyzing the occurrence probability of the perturbation coefficients, an MMSE-based optimization of perturbation coefficients quantization is proposed and demonstrated in ultra-large-area-fiber transmission systems with a 36Gbd DP-16QAM modulation format. Compared to conventional uniform quantization schemes, a significant reduction in quantization errors has been realized for both the real and imaginary parts of the perturbation coefficients. Compared with the nonquantization case, computational term reduction by a factor of 50 is achieved in 2400 km ULAF transmission with <; 0.2 dB Q degradation. For the same Q improvement, optimized quantization scheme further reduce the computational term by 50% compared to that of the uniform quantization method. We also analyze the tolerance to link dispersion.

Experimental comparison of terabit nyquist superchannel transmissions based on high and low baud rates

We report experimental results comparing two-types-of terabit Nyquist-pulse-shaped superchannel transmissions. A 50-subcarrier low-baud-rate system with potential of significant DSP simplification has shown similar transmission performance compared with a 10-subcarrier high-baud-rate system.

Optimum quantization of perturbation coefficients for perturbative fiber nonlinearity mitigation

MMSE-based optimum quantization of the perturbation coefficients for the perturbative nonlinearity mitigation is proposed and experimentally demonstrated. Computational term reduction by a factor of 20 is realized in 2400km ULAF 16QAM transmission with <;0.2dB Q degradation.

Extending perturbative nonlinearity mitigation to PDM-16QAM

For 16QAM, we propose a QAM decomposition method enabling simple processing of perturbative nonlinearity mitigation. After 1920-km SSMF, our simple approach exhibits only ~0.1-dB penalty compared with the complex conventional method and ~0.5-dB gain over the degenerate method.

1.2 Tb/s Superchannel Transmission Over 80

Employing 8-bit 65GSps digital-to-analog converters with pre-equalization and Nyquist pulse-shaping, we generated a terabit superchannel based on both low-baud-rate Nyquist frequency-division-multiplexing (FDM) dual polarization quadrature-phase-shift-keying (DP-QPSK) and high-baud-rate Nyquist DP-QPSK signals. The 1.2-Tb/s superchannel transmission over 80 × 100 km ultra-large-area fiber with effective area (Aeff) of 125 μm2 was demonstrated using erbium doped fiber amplifier only spans. We further discussed the roll-off factor (α) in Nyquist pulse-shaping on the system optimization. It has been found that the Nyquist FDM DP-QPSK signal outperforms the high-baud-rate Nyquist DP-QPSK. Given the same data capacity, the Nyquist FDM DP-QPSK scheme exhibits better tolerance to fiber nonlinearities.

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A QAM decomposition method for 16QAM signal and MMSE-based optimum quantization of perturbation coefficient method have been proposed and demonstrated experimentally. Computational term reduction by a factor of 20 is realized in 2400km ULAF transmission.

100 km ULAF Using Nyquist FDM DP-QPSK

In this paper we review the prior works on the fiber nonlinearity mitigation methods and compare their performance in a 12x80km SSMF link.

On the Reduction of Computational Complexity of Digital Fiber Nonlinearity Mitigation for 16QAM Signals

We discuss terabit superchannel transmission exploring low-baud-rate Nyquist pulse shaped subcarriers. This technique can enable the transmission with much smaller propagation penalty, while having the potential of significant reduction of power consumption.