Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
Sensors (Basel). 2018 Nov 29;18(12):4184. doi: 10.3390/s18124184.
An accelerometer utilising the optomechanical coupling between an optical whispering gallery mode (WGM) resonance and the motion of the WGM cavity itself was prototyped and field-tested on a vehicle. We describe the assembly of this portable, battery operated sensor and the field-programmable gate array automation. Pre-trial testing using an electrodynamic shaker demonstrated linear scale-factors with <0.3% standard deviation ( ± 6 g range where g = 9.81 ms - 2 ), and a strong normalised cross-correlation coefficient (NCCC) of r ICP / WGM = 0.997 when compared with an integrated circuit piezoelectric (ICP) accelerometer. A noise density of 40 μ g Hz - 1 / 2 was obtained for frequencies of 2⁻7 kHz, increasing to 130 μ g Hz - 1 / 2 at 200 Hz, and 250 μ g Hz - 1 / 2 at 100 Hz. A reduction in the cross-correlation was found during the trial, r ICP / WGM = 0.36, which we attribute to thermal fluctuations, mounting differences, and the noisy vehicle environment. The deployment of this hand-fabricated sensor, shown to operate and survive during ±60 g shocks, demonstrates important steps towards the development of a chip-scale device.
我们制作了一个样机，利用光 whispering gallery 模式（WGM）共振与 WGM 腔自身运动之间的光机械耦合来测量加速度，随后在一辆车上进行了现场测试。我们描述了这种便携式、电池供电传感器的组装以及现场可编程门阵列自动化过程。使用电动振动器进行的预测试表明，线性比例因子的标准偏差小于 0.3%（±6g 范围，其中 g = 9.81 ms - 2 ），与集成电路压电（ICP）加速度计相比，归一化互相关系数（NCCC）r ICP / WGM = 0.997 非常强。在 2⁻7 kHz 的频率下，获得了 40 μ g Hz - 1 / 2 的噪声密度，在 200 Hz 时增加到 130 μ g Hz - 1 / 2，在 100 Hz 时增加到 250 μ g Hz - 1 / 2。在试验过程中发现互相关系数降低，r ICP / WGM = 0.36，我们将其归因于热波动、安装差异和嘈杂的车辆环境。这种手工制作的传感器的部署表明，它可以在±60g 的冲击下正常运行和生存，这朝着开发芯片级设备迈出了重要的一步。
