报道了一种用高频CO2激光脉冲在普通通信光纤包层边缘单侧写入的新型长周期光纤光栅。研究发现,这种长周期光纤光栅的折射率变化主要发生在光纤包层区域,而纤芯的折射率变化较小;同时该光栅的附加损耗低于0.5 dB。进一步折射率特性实验研究表明,由于其特殊的折变结构,这种光栅具有较高的外界环境灵敏度,当外界折射率在1.41～1.45范围内变化时,其谐振波长漂移量高达15.52 nm,比实验测得的用传统方法写入的长周期光纤光栅谐振波长漂移量高出近3倍,这种光栅结构在光纤传感中将具有重要的应用。

A novel long-period fiber grating (LPFG) is fabricated in common communication optical fiber by using a edge-written exposure method with high-frequency CO2 laser pulses. Studies show that this kind of long-period fiber grating has refractive index disturbance mainly in cladding of optical fiber, and its excess loss is less than 0.5 dB. Experimental results of the refractive index characteristic show that it has a resonant peak shift of 15.52 nm when the surrounding refractive index varies in the range of 1.41～1.45, which is three times higher than that of a conventional long-period fiber grating due to especial refractive index disturbance. The novel long-period fiber grating can find important applications in the field of optical sensing.