研究了采用非对称双侧曝光技术实现长周期光纤光栅(LPFG)的传感特性的调整方法。非对称热应力作用的理论分析结果表明，先后两次热应力作用的角度差的不同，将导致长周期光纤光栅谐振峰向长波或短波方向漂移。实验结果与理论分析结果一致，得出了长周期光纤光栅谐振波长漂移方向随方位角度差的变化规律。这一特性可用于谐振波长可调的长周期光纤光栅的制作，也可用于构造光纤传感应用系统。

By using bi-direction of the fiber cross-section asymmetric CO2 laser pulses exposure approach, the long period fiber grating (LPFG) sensing characteristics can be controlled and improved. This fabrication method is to write the LPFG on one side by CO2 laser, and then write the LPFG again on the other side with the same grating pitch and exposure energy. Under the action of the two exposure directions, the fiber refractive index was periodically modulated twice. Asymmetric thermal stress analysis results shown that the resonant peak of LPFG can shift in direction of either shorter or longer wavelengths, depending on the angle difference Δθ between two exposure directions changes in the second writing process. It is confirmed by the experimental results. We found this technique could be used in wavelength tunable LPFG fabrication or fiber optic sensors design to control and improve the characteristics of the components.