基于耦合模理论,利用逆向递推传输矩阵方法,数值研究了光纤光栅透射输出端面存在反射时λ/4相移光栅的开关特性,以及啁啾的引入对其开关性能的影响.研究结果表明:对于反射相干叠加加强,可使λ/4相移光栅的阈值开关能量得到降低,但开关对比度将下降;在λ/4相移光纤光栅中引入负啁啾,能使开关对比度得到较大的提高,但双稳阈值开启能量会增加;引入正啁啾,可进一步降低开关阈值,但开关对比度会下降;啁啾的引入将对λ/4相移光栅的双稳环宽度产生较大影响. Based on the coupled mode theory and the inverse recursive transfer matrix method, the switching characteristics of the λ / 4 phase shift grating and the effect of the chirp on its switching performance are investigated numerically when the transmission output end of the fiber grating is reflected. The results show that: For the enhancement of reflection coherence, the threshold switching energy of λ / 4 phase shift grating can be reduced, but the switching contrast will decrease. Introducing negative chirp in λ / 4 phase shift fiber grating can greatly improve the switching contrast. , But the bistable threshold turns on the energy will increase; introducing a positive chirp can further reduce the switching threshold, but the switching contrast will decline; the introduction of chirp will have a greater impact on the bistable width of the λ / 4 phase shift grating.