Liu Yue, Zhang Yichi, Xu Zhiming, Zhou Libo, Zou Yongchao, Zhang Bingbing, Hu Zhengliang
Opt Express. 2022 May 23;30(11):18966-18977. doi: 10.1364/OE.455588.
The noise floor is a vital specification that determines the minimum detectable signal in the phase measurement. However, the noise floor in optical phase measurement conducted via conventional optical interferometry tends to approach the intrinsic limit. In this study, a low noise phase measurement of a fiber optic sensor conducted via weak value amplification is experimentally demonstrated. The system has a flat, wideband frequency response from 0.1 Hz to 10 kHz, as well as adequate linearity. The operating band is wider than the present sensor using the same mechanism. In particular, the system noise floor is measured to be -98 dB at 1 Hz and -155 dB at 1 kHz. The results indicate that the minimum detectable signal can reach as low as 5.6 × 10 rad at 1 Hz and 8 × 10 rad at 1 kHz. In addition, it is demonstrated that the noise result of the proposed system is two-order of magnitude lower than that of the typical interferometric fiber optic sensors through the comparison experiment. With the characteristic of low-noise, the system is promising in the field of weak signal detection such as underwater acoustic signal detection, seismic wave detection, and mineral resource exploration.
本底噪声是决定相位测量中最小可检测信号的一项重要指标。然而，通过传统光学干涉测量法进行的光学相位测量中的本底噪声往往接近固有极限。在本研究中，通过弱值放大对光纤传感器进行低噪声相位测量的实验得到了证明。该系统具有从0.1 Hz到10 kHz的平坦宽带频率响应以及足够的线性度。其工作频段比采用相同机制的现有传感器更宽。特别是，该系统的本底噪声在1 Hz时测得为 -98 dB，在1 kHz时为 -155 dB。结果表明，最小可检测信号在1 Hz时可低至5.6×10弧度，在1 kHz时为8×10弧度。此外，通过对比实验表明，所提出系统的噪声结果比典型干涉式光纤传感器低两个数量级。凭借低噪声特性，该系统在诸如水下声信号检测、地震波检测和矿产资源勘探等弱信号检测领域具有广阔前景。
