Current optical fibre transmission systems rely on modulation, coding and multiplexing techniques that were originally developed for linear communication channels. However, linear transmission techniques are not fully compatible with a transmission medium with a nonlinear response, which is the case for an optical fibre. As a consequence, the Kerr nonlinearity in fibre imposes a limit on the performance and the achievable transmission rate of the conventional optical fibre communication systems. Here we show that a transmission performance beyond the conventional Kerr nonlinearity limit can be achieved by encoding all the available degrees of freedom and nonlinearly multiplexing signals in the so-called nonlinear Fourier spectrum, which evolves linearly along the fibre link. This result strongly motivates a fundamental paradigm shift in modulation, coding and signal-processing techniques for optical fibre transmission technology.

中文翻译：

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超出Kerr非线性极限的用于通信的非线性信号多路复用

当前的光纤传输系统依赖于最初为线性通信信道开发的调制，编码和复用技术。但是，线性传输技术与具有非线性响应的传输介质并不完全兼容，这是光纤的情况。结果，光纤中的Kerr非线性限制了常规光纤通信系统的性能和可达到的传输速率。在这里，我们表明，通过对所有可用自由度进行编码并在所谓的非线性傅里叶频谱中对信号进行非线性复用，可以实现超出常规Kerr非线性限制的传输性能，该非线性傅里叶频谱沿着光纤链路线性发展。这一结果强烈地激发了调制的根本范式转变，