基于紫外刻写相移光栅的温度应力同时测量传感器

Simultaneous measurement sensor of temperature and stress based on UV lithography phase-shifted grating

传统光纤光栅传感器存在温度应力交叉敏感的问题,无法同时测量被测物体的温度应力变化情况。针对这种情况,提出一种新型的利用紫外光刻写相移光栅的方法,在刻写光栅前用电极放电的方法去除掉极小一段光纤的光敏性,使光纤原有的均匀周期分布状态被破坏,从而形成相移光栅,并对其进行理论分析。此种相移光栅的透射光谱存在2个明显的谐振峰,利用2个峰对温度和应变灵敏度不同的性质,可以通过建立解调矩阵来实现温度与应力的同时测量。实验结果表明:利用此种方法制成的相移布拉格光栅能够较为精确地实现温度、应力的同时测量,所制作的传感器温度灵敏度最高可达9.51 pm/℃,灵敏度方差低于2.125×10^(−7),应变灵敏度最高可达0.767 pm/με,灵敏度方差低于2.156×10^(−10)。

The traditional fiber grating sensors are cross-sensitive to temperature stress and cannot simultaneously measure the change of the temperature stress of the measured object.In view of this situation,a new method of lithographing phase-shifted gratings using ultraviolet light was proposed.Before lithographing the gratings,the method of electrode discharge was used to remove the photosensitivity of a very small section of the optical fiber,so that the original uniform periodic distribution of the fiber was destroyed to form a phaseshifted grating,and its theoretical analysis was carried out.There were two distinct resonance peaks in the transmission spectrum of this phase-shifted grating.Using the properties of two peaks with different sensitivity to temperature and dependent variable,the simultaneous measurement of temperature and stress could be achieved by establishing the demodulation matrix.The experimental results show that the phase-shifted Bragg grating made by this method can realize the simultaneous measurement of temperature and stress accurately.The maximum temperature sensitivity of the sensor can reach to 9.51 pm/℃,and the sensitivity variance is lower than 2.125×10^(−7).The maximum strain sensitivity can reach to 0.767 pm/με,and the sensitivity variance is lower than 2.156×10^(−10).