Zhang Fengchan, Xu Xizhen, He Jun, Du Bin, Wang Yiping
Opt Lett. 2019 May 15;44(10):2466-2469. doi: 10.1364/OL.44.002466.
A highly sensitive temperature sensor is proposed and demonstrated based on a UV-curable polymer-infiltrated Mach-Zehnder interferometer (MZI) created in a graded index fiber (GIF). The device was constructed by splicing a half-pitch GIF between two single-mode fibers and creating an inner air cavity in one lateral side of the GIF core by means of femtosecond laser micromachining. The air cavity and the residual GIF core functioned as two interference arms of the MZI. Moreover, the GIF was used as a miniature in-fiber collimator to reduce insertion loss of the air cavity. Experimental results show such an MZI device has a high refractive index (RI) sensitivity of 24611.54 nm/RIU (RI=1.545-1.565). Subsequently, thermo-sensitive polymer liquid was infiltrated into the air cavity, then cured with UV illumination, and annealed at 50°C for 12 h. The infiltrated MZI exhibits a high temperature sensitivity of -13.27 nm/°C. In addition, this MZI also has excellent thermal stability and repeatability, compact structure, low insertion loss, and high fringe visibility. As such, the proposed MZI could be developed for high-accuracy temperature measurements in many areas such as biomedical or oceanographic applications.
基于在渐变折射率光纤（GIF）中创建的紫外光固化聚合物浸润马赫-曾德尔干涉仪（MZI），提出并演示了一种高灵敏度温度传感器。该器件通过在两根单模光纤之间熔接一个半节距GIF，并利用飞秒激光微加工在GIF纤芯的一侧创建一个内部空气腔来构建。空气腔和剩余的GIF纤芯作为MZI的两个干涉臂。此外，GIF用作微型光纤准直器以降低空气腔的插入损耗。实验结果表明，这种MZI器件具有24611.54 nm/RIU（RI = 1.545 - 1.565）的高折射率（RI）灵敏度。随后，将热敏聚合物液体浸润到空气腔中，然后用紫外光照射固化，并在50°C下退火12小时。浸润后的MZI表现出-13.27 nm/°C的高温度灵敏度。此外，这种MZI还具有出色的热稳定性和重复性、紧凑的结构、低插入损耗和高条纹可见度。因此，所提出的MZI可用于生物医学或海洋学应用等许多领域的高精度温度测量。
