Combining IP with WDM is an attractive direction for research. WDM will play an impor-tant role in IP network in future. Now, an urgent problem is how to introduce wavelength routing in an IP network. We solve this problem by designing IP wavelength router, implementing DPDP (default path and dedicated path) method. We prove the reasonableness and feasibility of this design by a prin-ciple experiment. A lot of problems related to this design are also discussed.

Under the guidance of the related theory detailed in this paper, we propose to construct optical packet buffer element used in the optical packet switched networks (OPSN) with electromagnetically induced transparency (EIT) medium. Two different types of buffers (i.e., traveling-type buffer and storing-type buffer) and corresponding buffer structures constructed with them are given.

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.

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.