在国内首次研制了使用1个光纤放大器的10频道102km无再生中继“WDM+EDFA”全光光纤传输实验系统。每频道传输码率为140Mb/s或280Gb/s NRz。所用光纤放大器为增苴平坦型，小信号增苴为35dB。系统全部采用国产DFB激光器，奋频道连长分别为153l、1535、1537、1545、1547、1549、155l、1559、156lnm，在波长为155lnm的频道内布置了2路频分复用（FDM）系统。波长分市遍及整个光纤放大器的通带。经无再生中继传输102km后，在误码丰为1×10-9条件下，实测了尚有数dB以上（最大为12dB）的功丰裕量。系统使用光栅合、分波器作为波分复用和解复用器，频道间隔为2nm及其整数倍，系统具有18个频道的能力。

A five-node, eight-channel, wave-length division multiplexing (WDM) experimental all-optical network is present in China. The network has nodes of three 0ADMs and two OXCs, management function and self-healing function. Digital signal of 2.5 Gbit/s and analogue signals of CATV can be trans-mitted through and cross-connected. BER is less than 1.5

This paper is contributed to discuss the impacts of group velocity dispersion, nonlinear Kerr effect and polarization mode dispersion in optical fibers. Using split-step Fourier method, we first analytically analyze that the interaction of Kerr effect and polarization mode dispersion results in the pulse asymmetric spectra. Then we study that polarization mode dispersion and group velocity dispersion play their roles independently, and that, depending on the relative magnitudes, the two factors affect the pulse differently. Finally, we research the combined impacts of group velocity dispersion, Kerr effect and polarization mode dispersion. Detailed investigation reveals that the combined effects are different in anomalous and normal group velocity dispersion regime. We point out that increased Kerr effect can suppress the impact of polarization mode dispersion in anomalous chromatic dispersion regime, and that, for the given values of incident power and polarization mode dispersion, anomalous group velocity should be large enough for the polarization mode dispersion to be effectively suppressed by the Kerr effect.

在国内首次研制了10频道、102km无再生中继使用1个平坦增益光纤放大器的WDM光纤传输实验系统。每频道传输码率为140Mb/s（223-1 NRZ PRBS 或CMI PRBS）。系统全部采用国产DFB激光器，它们的波长分别为1531nm、1535nm、1537nm、1545nm、1547nm、1549nm、1551nm、1559nm、1561nm，在波稀薄为1551nm的频道内布置了2路频率间隔为10GHz的频分复用（FDM）系统，波长分布遍及整个光纤大器的通带。10个频道传输102km后，在误码率为1×10-2条件下，实测尚有数SB（最大为12dB）的功率裕量。系统使用了具有18个频道的能力且频道间隔为2nm的光■合、分波器，作为波分复用的解复用器。

Three group velocity dispersion (GVD) compensation schemes, i.e., the post-compensation, pre- compensation and hybrid-compensation schemes, are discussed with considering polarization mode disper-sion (PMD). In the 10- and 40-Gbit/s non-return-zero (NRZ) on-off-key (0OK) systems, three physical factors, Kerr effect, GVD and PMD are considered. The numerical results show that, when the impact of PMD is taken into account, the GVD pre-compensation scheme performs best with more than 1 dB better of average eye-opening penalty (EOP) when input power is up to 10dBm in the 10-Gbit/s system. However the GVD post-compensation scheme performs best for the case of 40 Gbit/s with input power less than 13dBm, and GVD pre-compensation will be better if the input power increased beyond this range. The results are different from those already reported under the assumption that the impact of PMD is neglected. Therefore, the research in this paper provide a different insight into the system optimization when PMD. Kerr effect and GVD are considered.