EL Ginzton Laboratory, Stanford University, 348 Via Pueblo Mall, Stanford, California 94305, USA.
J Acoust Soc Am. 2011 Apr;129(4):1837-50. doi: 10.1121/1.3543949.
This work reports on an optical hydrophone that is insensitive to hydrostatic pressure, yet capable of measuring acoustic pressures as low as the background noise in the ocean in a frequency range of 1 Hz to 100 kHz. The miniature hydrophone consists of a Fabry-Perot interferometer made of a photonic-crystal reflector interrogated with a single-mode fiber and is compatible with existing fiber-optic technologies. Three sensors with different acoustic power ranges placed within a sub-wavelength sized hydrophone head allow a high dynamic range in the excess of 160 dB with a low harmonic distortion of better than -30 dB. A method for suppressing cross-coupling between sensors in the same hydrophone head is also proposed. A prototype was fabricated, assembled, and tested. The sensitivity was measured from 100 Hz to 100 kHz, demonstrating a sound-pressure-equivalent noise spectral density down to 12 μPa/Hz(1/2), a flatband wider than 10 kHz, and very low distortion.
本文报道了一种对静压不敏感的光学水听器，它能够在 1 Hz 至 100 kHz 的频率范围内测量低至海洋背景噪声的声压。该微型水听器由一个光子晶体反射器构成的法布里-珀罗干涉仪组成，通过单模光纤进行检测，与现有的光纤技术兼容。三个具有不同声功率范围的传感器放置在亚波长尺寸的水听器探头内，可提供超过 160 dB 的高动态范围，谐波失真优于-30 dB。还提出了一种抑制同一水听器探头中传感器之间交叉耦合的方法。制作、组装并测试了一个原型。从 100 Hz 到 100 kHz 测量了灵敏度，展示了低至 12 μPa/Hz(1/2)的声压等效噪声谱密度、超过 10 kHz 的宽带和非常低的失真。
