Nonlinear frequency division multiplexing (NFDM) systems have been showing remarkable progress in the past few years. However, the majority of the demonstrations have neglected the impact of laser phase noise by employing narrow-linewidth lasers and self-homodyne receivers. The impact of transmitter laser linewidth on NFDM transmission is here numerically and experimentally investigated for dual-polarization discrete NFDM systems. The scaling of linewidth tolerance is analyzed for different signal symbol rates and the results are validated experimentally at 250 MBd. Numerical and experimental analysis show a limited degradation due to laser phase noise with relevant penalty appearing only for linewidth-symbol duration products ( $\Delta \nu \times T_{s}$ ) above $10^{-3}$ . The 250-MBd experimental results indeed show limited penalty for laser linewidths up to 750-kHz and 100-kHz, for back-to-back and 2000-km transmission, respectively.

中文翻译：

---

发射机相位噪声对离散频谱调制的 NFDM 传输的影响

非线性频分复用 (NFDM) 系统在过去几年中取得了显着进展。然而，大多数演示都忽略了采用窄线宽激光器和自零差接收器的激光器相位噪声的影响。发射器激光线宽对 NFDM 传输的影响在这里对双偏振离散 NFDM 系统进行了数值和实验研究。针对不同的信号符号率分析了线宽容差的缩放比例，结果在 250 MBd 下进行了实验验证。数值和实验分析表明，由于激光相位噪声造成的退化有限，相关惩罚只出现在线宽-符号持续时间乘积中（ $\Delta \nu \times T_{s}$ ） 以上 $10^{-3}$ . 250-MBd 的实验结果确实表明，对于背对背和 2000 公里的传输，最高 750-kHz 和 100-kHz 的激光线宽的损失有限。