Field trial yquist-WDM transmission of 8×216.4Gb/s PDM-CSRZ-QPSK exceeding 4b/s/Hz spectral efficiency

Jianjun Yu, Ze Dong, Hung Chang Chien, Zhensheng Jia, Di Huo, Hong Yi, Meng Li, Zhiliang Ren, Nan Lu, Li Xie, Kai Liu, Xiaochao Zhang, Yan Xia, Yao Cai, Matthias Gunkel, Paul Wagner, Heinz Mayer, Achim Schippel