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.

Although routing schemes based on global knowledge make most optimal routing decisions, they will occupy many resources to keep the state information of the network up-to-date. In tiffs work, we describe a fuzzy least-congested path (FLCP) routing algorlitm based on hierarchical liformation. Simulation shows that the blocking probability using FLCP is very near to the blocking probability using the least-congested path routing (LCP) algorittm based on global information. Under heavy traffic load, the FLCP alg orlihm is superior to the exhaustive algorittm (EA) and the LCP algorittm with unit information cost. The FLCP algorlitm provides better routing, even withincomplete information. Thus, the algorlitm requires less information of the network, particularly under heavy traffic load. In addition, an improved remote-path routing approach is provided to reduce the blocking probability of connection requests to a node that is many hops away from the source node.