采用级联多个长周期光纤光栅的方法有效拓宽了长周期光纤光栅反射谱带宽。分析了LPFG透射谱的谐振峰的定位问题,并通过级联多段周期相同但长度和微扰不同的LPFG来形成一个级联型的长周期光纤光栅,然后通过使用传输矩阵的方法,对级联光栅的传输谱进行了数值分析。经过分析发现,如果适当地调整级联型长周期光纤光栅的各个参数如级联的段数以及各段的长度和微扰等值,则所得到的这个级联型长周期光栅的透射谱的有效带宽将显著地增大,其透射谱的形状也会发生显著改变。 The method of cascading multiple long-period fiber gratings effectively broadens the reflection spectrum bandwidth of long-period fiber gratings. The location problem of resonance peak in LPFG transmission spectrum was analyzed. A cascaded LPFG was formed by cascading LPFGs with the same period but different length and perturbation. Then by using the method of transfer matrix, The transmission spectrum of the grating was numerically analyzed. After analysis, it is found that if the parameters of cascade long-period fiber gratings are properly adjusted, such as the number of cascades and the length and perturbation of each section, the transmission spectrum of this cascaded long-period grating is valid The bandwidth will be significantly increased, and the shape of the transmission spectrum will change significantly.