Time-Domain Learned Digital Back-Propagation
Time-Domain Learned Digital Back-Propagation
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DOI：
10.1109/sips50750.2020.9195253
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
E. Sillekens;Wenting Yi;Daniel Semrau;Alessandro Ottino;B. Karanov;D. Lavery;L. Galdino;P. Bayvel;R. Killey;Sujie Zhou;K. Law;Jack Chen
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文献类型：
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作者：
E. Sillekens;Wenting Yi;Daniel Semrau;Alessandro Ottino;B. Karanov;D. Lavery;L. Galdino;P. Bayvel;R. Killey;Sujie Zhou;K. Law;Jack Chen
通过数字化反转通道环境可以提高光纤传输的性能。当通过分离色散和克尔非线性来模拟短段来实现这一点时，这称为数字反向传播（DBP）。时域 DBP 有可能降低频域算法的复杂性。然而，当在算法中使用更精细的步骤时，各个较小步骤的准确性会受到影响。通过使各个步骤的色散滤波器适应模拟或测量数据，可以缓解这个问题。机器学习框架已经为大型算法实现了梯度下降风格的适应。这允许采用许多色散滤波器来准确地表示反向传输。所提出的技术已用于学习时域 DBP 的实验演示，该实验演示使用四通道 64-GBd 双极化 64-QAM 信号传输，在总长 1014 km 的 10 跨度循环环路上进行传输。信号处理方案由具有非线性相移的交替有限脉冲响应滤波器组成，其中滤波器系数使用实验测量进行调整。线性补偿在信噪比改进方面的性能增益与传统频域 DBP 所实现的性能增益相当。我们的实验研究表明，具有学习参数的数字信号处理技术在提高高数据速率长距离光纤传输系统性能方面具有潜力。
Performance for optical fibre transmissions can be improved by digitally reversing the channel environment. When this is achieved by simulating short segment by separating the chromatic dispersion and Kerr nonlinearity, this is known as digital back-propagation (DBP). Time-domain DBP has the potential to decrease the complexity with respect to frequency domain algorithms. However, when using finer step in the algorithm, the accuracy of the individual smaller steps suffers. By adapting the chromatic dispersion filters of the individual steps to simulated or measured data this problem can be mitigated. Machine learning frameworks have enabled the gradient-descent style adaptation for large algorithms. This allows to adopt many dispersion filters to accurately represent the transmission in reverse. The proposed technique has been used in an experimental demonstration of learned time-domain DBP using a four channel 64-GBd dual-polarization 64-QAM signal transmission over a 10 span recirculating loop totalling 1014 km. The signal processing scheme consists of alternating finite impulse response filters with nonlinear phase shifts, where the filter coefficient were adapted using the experimental measurements. Performance gains to linear compensation in terms of signal-to-noise ratio improvements were comparable to those achieved with conventional frequency-domain DBP. Our experimental investigation shows the potential of digital signal processing techniques with learned parameters in improving the performance of high data rate long-haul optical fibre transmission systems.