利用变分法研究三芯非线性光纤耦合器中的短脉冲光开关 ,解析分析线性三耦合非线性Schr dinger方程的结果与数值模拟符合得很好 .并且得到在非线性光纤耦合器中孤子的耦合长度和开关阈值 ,与连续波情况和两芯光纤耦合器的结果不同 . Using the variational method to study the short-pulse optical switch in a three-core nonlinear optical fiber coupler, the analytical results of the linear three-coupling nonlinear Schr dinger equation are in good agreement with the numerical simulations, and the soliton in the nonlinear fiber coupler The coupling length and the switching threshold differ from the results of the continuous wave case and the two-core fiber coupler.