为了探索一种高灵敏折射率传感器，基于CO₂激光技术制备出双峰谐振长周期光纤光栅（LPFG）。首先，利用CO₂激光器在腐蚀包层后的传统单模光纤和80 μm弯曲不敏感光纤上制备出周期分别为196 μm和73 μm的双峰谐振LPFG，证明了采用CO₂激光微加工技术在单模光纤上制备短周期LPFG的可能性。其次，利用CO₂激光器直接在2种80 μm单模光纤上制备出周期分别为110 μm和115 μm的双峰谐振LPFG。实验结果表明：在2种80 μm单模光纤上制备的LPFG具有谐振损耗大，插入损耗小和折射率灵敏度高等优点。基于以上优点，采用CO₂激光技术制备的双峰谐振LPFG在生物、化学及环境参数检测等重要领域的应用具有较大潜力。同时，也提供了一种操作简单、低成本制备双峰谐振LPFG的方法。

A dual-peak resonance long-period fiber grating (LPFG) based on CO₂ laser technology is proposed to investigate a highly sensitive refractive index sensor. First, dual-peak resonance LPFGs with grating periods of 196 and 73 μm are fabricated in conventional single-mode fiber and 80 μm bend-insensitive single-mode fiber, respectively,using a CO₂ laser after etching cladding. This demonstrates the possibility of fabricating an LPFG on a single-mode fiber with a shorter grating period using CO₂ laser micromachining technology. Dual-peak resonance LPFGs with grating periods of 110 and 115 μm are directly fabricated in two 80 μm single-mode fibers using a CO₂ laser. The results show that the dual-peak resonance LPFGs fabricated in two 80 μm thin single-mode fibers exhibit advantages of deep attenuation loss, low loss, and high refractive index sensitivity. Based on its excellent performance, the dual-peak resonance LPFG based on CO₂ laser technology is a prospective sensor applicable to fields such as biological, chemical, and environmental parameter detection. In addition, a simple-operation low-cost method for fabricating dual-peak resonance LPFGs is proposed.