Mao Chun, Huang Bo, Wang Ying, Huang Yijian, Zhang Longfei, Shao Yu, Wang Yiping
Opt Express. 2018 Nov 12;26(23):30108-30115. doi: 10.1364/OE.26.030108.
We propose and experimentally demonstrate a highly sensitive gas pressure sensor based on a near-balanced Mach-Zehnder interferometer (MZI) and constructed by hollow-core photonic bandgap fiber (HC-PBF) in this paper. The MZI is simply constructed by fusion splicing two HC-PBFs, which are of slightly different lengths, between two 3-dB couplers. The two output ends of each coupler are approximately equal in length, to ensure that the optical path variations of the MZI only result from the differences in the lengths between the two HC-PBFs. To apply the MZI for gas pressure sensing, a femtosecond laser is employed to drill a micro-channel in one of the two HC-PBF arms. The experiment result shows that the proposed MZI based gas pressure sensor achieves an ultrahigh sensitivity, up to 2.39 nm/kPa, which is two orders of magnitude higher than that of the previously reported MZI-based gas pressure sensors. Additionally, the effects resulting from the absolute length and relative length of the two HC-PBFs on gas pressure sensing performance are also investigated experimentally and theoretically, respectively. The ultra-high sensitivity and ease of fabrication make this device suitable for gas pressure sensing in the field of industrial and environmental safety monitoring.
本文提出并通过实验证明了一种基于近平衡马赫-曾德尔干涉仪（MZI）且由空心光子带隙光纤（HC-PBF）构建的高灵敏度气压传感器。该MZI通过在两个3 dB耦合器之间熔接两根长度略有不同的HC-PBF简单构建而成。每个耦合器的两个输出端长度近似相等，以确保MZI的光路变化仅由两根HC-PBF之间的长度差异引起。为了将MZI应用于气压传感，采用飞秒激光在两根HC-PBF臂中的一根上钻出一个微通道。实验结果表明，所提出的基于MZI的气压传感器实现了超高灵敏度，高达2.39 nm/kPa，比先前报道的基于MZI的气压传感器高两个数量级。此外，还分别通过实验和理论研究了两根HC-PBF的绝对长度和相对长度对气压传感性能的影响。这种超高灵敏度和易于制造的特点使得该器件适用于工业和环境安全监测领域的气压传感。
