对长周期光纤光栅和双锥形光纤之间的倏逝波耦合作用进行了研究。理论分析和实验研究表明,由于锥形光纤和长周期光纤光栅物理边界外倏逝波之间的交叠,长周期光纤光栅产生的包层模,可以耦合到锥形光纤的包层模并从锥形光纤的纤芯输出。要获得高的耦合效率,应满足模式匹配的条件,同时要尽量减小两光纤之间的距离。耦合特性还与长周期光栅和双锥形光纤的相对位置有关,为获得高的耦合效率,耦合区应位于长周期光栅区的后面。这种倏逝波耦合作用,为监测实际应用系统中长周期光纤光栅的特性提供了一种新方法;为利用锥形光纤和长周期光纤光栅开发新型光纤器件,提供了一种可能的方案。 Evanescent coupling between long-period fiber gratings and biconical fibers has been studied. Theoretical analysis and experimental studies show that due to the overlap between the evanescent waves outside the physical boundary of the tapered fiber and the long-period fiber grating, the cladding modes produced by the long-period fiber grating can be coupled to the cladding modes of the tapered fiber and removed from Conical fiber core output. To achieve high coupling efficiency, the conditions for pattern matching should be met while minimizing the distance between the two fibers. The coupling characteristics are also related to the relative positions of long-period gratings and double-tapered fibers. To obtain high coupling efficiency, the coupling region should be located behind the long-period grating region. The evanescent coupling function provides a new method for monitoring the characteristics of long-period fiber gratings in practical applications. It provides a possible solution for the development of new optical fiber devices using tapered fibers and long-period fiber gratings.