Liu Changning, Tao Wuqiang, Chen Cong, Liao Yang
College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002, China.
State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai 201800, China.
Micromachines (Basel). 2022 Dec 30;14(1):101. doi: 10.3390/mi14010101.
In this paper, a hollow core fiber was spliced with standard single-mode fibers to form a fiber optic gas pressure sensor, and its sensing characteristics with single hole or multi-holes punched on the hollow core fiber with femtosecond laser pulses were investigated. The experiments demonstrate that the air pressure sensitivity of the single hole sensor was -3.548 nm/MPa, with a linearity of 99.45%, while its response times for air pressure's rise and fall were 4.25 s and 2.52 s, respectively. The air pressure sensitivity of the ten-hole sensor was up to -3.786 nm/MPa, with a linearity of 99.47%, while its response times for air pressure's rise and fall were 2.17 s and 1.30 s, respectively. Theoretical analysis and experimental results indicate that the pressure sensitivity of the sensor with an anti-resonant reflecting guidance mechanism mainly comes from the refractive index change of the air inside the hollow core fiber. The proposed device with multi-holes drilled by a femtosecond laser has the advantages of fabrication simplicity, low cost, fast response time, good structural robustness, high repeatability, high sensitivity to air pressure, and insensitivity to temperature (only 10.3 pm/°C), which makes it attractive for high pressure sensing applications in harsh environments.
本文将空心光纤与标准单模光纤进行熔接，制成了一种光纤气压传感器，并研究了用飞秒激光脉冲在空心光纤上打出单孔或多孔时该传感器的传感特性。实验表明，单孔传感器的气压灵敏度为-3.548 nm/MPa，线性度为99.45%，其气压上升和下降的响应时间分别为4.25 s和2.52 s。十孔传感器的气压灵敏度高达-3.786 nm/MPa，线性度为99.47%，其气压上升和下降的响应时间分别为2.17 s和1.30 s。理论分析和实验结果表明，具有反谐振反射导光机制的传感器的压力灵敏度主要源于空心光纤内部空气的折射率变化。所提出的用飞秒激光打孔的多孔器件具有制作简单、成本低、响应时间快、结构稳健性好、重复性高、对气压灵敏度高以及对温度不敏感（仅10.3 pm/°C）等优点，这使其在恶劣环境下的高压传感应用中具有吸引力。
