在未来的通信领域中，全光逻辑门是全光计算机和全光网络的基本单元。目前已经提出了很多实现全光逻辑门的结构和方法，但是全光逻辑的技术瓶颈也出现了，就是怎样能够将单个的全光逻辑门级联起来实现更复杂的逻辑关系。现存的全光逻辑门结构一般不具有很好的可以实现多级连接的级联性，而且现有的对于级联性的分析大都停留在理论层面，而没有与实际情况相结合，所以对于实际应用来说意义很小。提出了一种新型的基于高非线性Sagnac干涉仪的超高速全光NOT门，建立了它的数学模型，采用了与实际情况更加接近的高斯脉冲模拟输入光，并且在仿真结果的基础上分析了系统的级联性，对级联性的分析考虑了光纤损耗和走离效应的影响。得到的基本结论表明，所提出的全光逻辑门的结构能够在实际情况下保持良好的级联性。

All-optical logic gates are the basic unit of all-optical computer and all-optical network in the field of communication in the future. A variety of structures and methods has been proposed for the implementation of all-optical logic gate, however, the bottleneck of this technique has emerged, which is how to cascade the individual all-optical logic gates to achieve more complex logical relationships. The existing schemes for all-optical logic gate, generally, don’t have excellent cascade to realize multilevel connection. And the existing analysis on the cascade usually stays on the theoretical level without combination with the realistic situation, which have little sense for the practical application. This work has presented a novel ultrafast all-optical NOT gate based on high nonlinear Sagnac interferometer, has built its mathematical model and digital model, has adopted Gauss pulse as input light for simulation, which is more realistic, and has analyzed the system cascade on the basis of simulation results. The analysis of cascade has taken into account the influence of fiber loss and walk-off effect. The basic conclusions in this article show that the proposed scheme of all-optical logic gates can maintain excellent cascade under practical situation with interference factors.