He Jianqing, Li Jianping, Qin Yuwen, Yu Xinkuo, Huang Tao, Zhang Jianbo, Zhou Gai, Fu Songnian
Opt Lett. 2024 Aug 15;49(16):4489-4492. doi: 10.1364/OL.530504.
Aiming to further improve the spectral efficiency (SE) of a continuous spectrum modulated nonlinear frequency division multiplexing (CS-NFDM) system, we propose a novel ,to the best of our knowledge, multiple-signal-joint-processing (MSJP)-based guard interval (GI) shortening method. In this method, multiple NFDM time-domain signals are jointly processed as a whole to carry out nonlinear Fourier transform and inverse nonlinear Fourier transform (NFT-INFT) operations. These operations can fuse the multiple NFDM time-domain signals together, which is equivalent to the corresponding inverse process of a fiber transmission. Experimental results show that the normalized SE of the proposed method can reach 0.99 when approaching the limit value of 1 and obtain a 2.33 dB Q-factor improvement compared with the pre-dispersion compensation (PDC) method under the same GI of 0.03 ns in an 80 km SSMF transmission of a 46 GHz signal bandwidth. Furthermore, in comparison with the PDC method, the proposed method can achieve 32.86% normalized SE improvement in the 1120 km SSMF transmission of 32 GHz signal bandwidth under the SD-FEC of 2.4E-2.
为了进一步提高连续谱调制非线性频分复用（CS-NFDM）系统的频谱效率（SE），据我们所知，我们提出了一种基于多信号联合处理（MSJP）的新型保护间隔（GI）缩短方法。在该方法中，多个NFDM时域信号被作为一个整体进行联合处理，以执行非线性傅里叶变换和逆非线性傅里叶变换（NFT-INFT）操作。这些操作可以将多个NFDM时域信号融合在一起，这等效于光纤传输的相应逆过程。实验结果表明，在46 GHz信号带宽的80 km单模光纤（SSMF）传输中，当接近极限值1时，所提方法的归一化SE可达0.99，并且在相同的0.03 ns保护间隔下，与预色散补偿（PDC）方法相比，品质因数提高了2.33 dB。此外，与PDC方法相比，在误码率为2.4E-2的软判决前向纠错（SD-FEC）下，所提方法在32 GHz信号带宽的1120 km SSMF传输中可实现32.86%的归一化SE提升。
