设计了一种低开关功率的全光开关.将掺铒光纤和微结构光纤引入Sagnac环镜中，信号光在泵浦光作用下经过掺铒光纤被放大，破坏了环镜的平衡，利用交叉相位调制效应使两束反向传输的信号光产生非线性相移，实现了光开关效应.理论分析表明：信号光经过掺铒光纤后，增益越大微结构光纤的非线性系数越高，开关功率越低，并且环镜信号光的透射率随两束反向传输信号光的相移差成余弦变化.仿真得到开关功率约为26.73 mW，与理论分析一致.

A low switchingpower alloptical switch was designed. The erbiumdoped fiber and the microstructure fiber were inserted into the Sagnac loop mirror simultaneously. Under the effect of the pump modulation, signal light was amplified when passing the erbiumdoped fiber. The symmetry of the loop was broken, two counterpropagating signal lights in the loop acquire nonlinear phase due to the crossphase modulation effect, and the light switch was realized. The theoretical analysis shows that while the signal light goes through erbiumdoped, the larger gain it gets, and the higher coefficients of the microstructure fiber is, the lower switch power is. Furthermore, the transmission rate of signal light in the loop varies with the phase difference of the two counterpropagating signal lights into cosine changes. the simulation results shows that switching power is 26.73 mW, which agrees with the theory.