Wang Wenhua
School of Electronic and Information Engineering, Guangdong Ocean University, Zhanjiang 524088, China.
Materials (Basel). 2022 Mar 28;15(7):2484. doi: 10.3390/ma15072484.
Due to the small difference between the thermal expansion coefficients of silica optical fiber and silica glass, they are used as probe materials of optical fiber acoustic wave sensors. According to the light absorption characteristics of a pressure-sensitive silica diaphragm and silica glass, the laser welding of an all-silica Fabry-Perot (FP) interference optical fiber acoustic wave sensor with a CO laser is proposed. For understanding the influence of thermal expansion of sealing air in an FP cavity and the drift of interference-intensity demodulation working point of a FP interference acoustic wave sensor, we designed a process for the laser welding of an ultra-thin silica diaphragm and sleeve and optical fiber and sleeve. The exhaust hole of the FP cavity is reserved in the preparation process, and an amplified spontaneous emission light source and a tunable optical-fiber FP filter are introduced to stabilize the working point. The sensor is tested with a 40 kHz sound vibration signal. The results show that the sound pressure sensitivity of the sensor to an acoustic source of 0.02-0.1 W/cm is 6.59 mV/kPa. The linearity coefficient is 0.99975, indicating good linearity.
由于石英光纤与石英玻璃的热膨胀系数差异较小，它们被用作光纤声波传感器的探头材料。根据压敏石英膜片和石英玻璃的光吸收特性，提出了采用CO激光器对全石英法布里-珀罗（FP）干涉型光纤声波传感器进行激光焊接的方法。为了解FP腔中密封空气的热膨胀以及FP干涉型声波传感器干涉强度解调工作点的漂移的影响，我们设计了一种超薄石英膜片与套管以及光纤与套管的激光焊接工艺。在制备过程中保留FP腔的排气孔，并引入放大自发辐射光源和可调谐光纤FP滤波器来稳定工作点。该传感器用40kHz的声振动信号进行测试。结果表明，该传感器对0.02 - 0.1W/cm声源的声压灵敏度为6.59mV/kPa。线性系数为0.99975，表明线性良好。
