铌酸锂晶体波导散斑温度传感器的研究

Study on Speckle Temperature Sensor With Lithium Niobate Crystal Waveguide

采用飞秒激光直写技术在铌酸锂晶体中写入圆柱形包层光波导,利用激光在波导中传输所产生的散斑,基于平均散斑强度变化算法实现了对外界温度的传感,并验证了波导芯径对传感灵敏度的影响。实验证明,该传感器对温度的传感精度可达0.05℃,其动态范围可达20℃,且芯径为60μm的光波导较30μm光波导的传感灵敏度更高。该方案凭借晶体波导几何尺寸的特征,有效减小了传感系统的体积,并进一步拓展了晶体波导在集成光学系统中的应用。

The cylindrical cladding optical waveguides were fabricated in lithium niobate crystal by using the method of femtosecond laser direct writing.The temperature sensor,using the specklegram generated from laser transmissing in the waveguide,was achieved based on the average speckle intensity variation algorithm.And the influence of the core diameter of the waveguide on the sensitivity of the sensor was verified.Experimental results show that the temperature sensing resolution of this sensor can reach 0.05℃,and its dynamic range can reach20℃.The sensitivity of the optical waveguide with a core diameter of 60μm is much higher than that of the 30μm optical waveguide.The scheme effectively reduces the volume of the sensing system by virtue of the geometrical size of the crystal waveguide,and further expands the applications of the crystal waveguide in the integrated optical system.