银薄膜结构的高灵敏度Fabry-Perot光纤声压传感器

High sensitivity Fabry-Perot fiber acoustic pressure sensor based on large area silver diaphragm

为改善膜片式Fabry-Perot光纤声压传感器中悬空薄膜的平整度,提高其检测微弱声压的能力,提出一种大面积银薄膜转移加工方法.采用磁控溅射沉积银薄膜,利用基于正性光刻胶的牺牲层工艺进行转移贴合.银薄膜直径为2.5 mm,厚度为130 nm.实验结果表明:银薄膜薄膜表面平整度<20μm;加工得到的声压传感器在0.13.0 k Hz频带范围内具有一致的频响特性,在1 k Hz处的声压灵敏度为-158 d B(参考值1 V/μPa).在0.0011.250 Pa声压范围内,传感器输出响应与入射声压之间具有良好的线性关系;最小可探测声压为419μPa·Hz-0.5.所提出的加工方法可有效改善薄膜的平整性,并具有良好的工艺性和可重复性;加工得到的传感器适应于高灵敏度微弱声压探测工作.

In order to improve the flatness of the diaphragm and the ability of the diaphragm-based Fabry-Perot fiber acoustics sensor to detect weak acoustics signal,a large area silver diaphragm was fabricated by sputtered. The diaphragm was then transferred to the sensor head with a sacrifice layer. The diaphragm is as thin as 130 nm,while its diameter is 2.5 mm. Experimental result demonstrate that the flatness of the diaphragm is less than 20 μm. The fabricated sensor＇s sensitivity is about-158 d B（ re 1 V / μPa） with a high linear pressure response range of 0.001-1.250 Pa. The noise equivalent acoustic signal level of 419 μPa·Hz-0.5at 1 k Hz. The sensor exhibits a flat frequency response in the range of 0.1 k Hz to 3 k Hz. The diaphragm＇s flatness is improved by the proposed method and the fabricated sensor is suitable to be useful for highly sensitive measurement of the weak pressure and sound field.