We report on the development and implementation of an optical frequency-domain reflectometer (OFDR) sensing platform. OFDR allows to measure changes in strain and temperature using optical fibers with a length of several tens of meters with very high spatial resolution. We discuss the operation principles and challenges to implement an OFDR system using optical homodyne detection based on a dual-polarization 90° optical hybrid. Our setup exhibits polarization and phase diversity, fully automated data acquisition and data processing using a LabVIEW-based implemented software environment. Using an optical hybrid enables to discriminate phase, amplitude and polarization by interfering the Rayleigh scatter signal and a local oscillator with four 90° phase stepped interferences between the two signals. Without averaging and a fast acquisition time of 230 ms, our preliminary results show a spatial resolution of 5 cm and a temperature resolution of about 0.1 Kelvin on a 3 m-long fiber.

中文翻译：

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使用 I/Q 零差检测实现偏振不敏感光频域反射计

我们报告了光频域反射计 (OFDR) 传感平台的开发和实施。OFDR 允许使用具有非常高空间分辨率的几十米长的光纤测量应变和温度的变化。我们讨论了使用基于双偏振 90° 光学混合的光学零差检测来实现 OFDR 系统的操作原理和挑战。我们的设置展示了极化和相位多样性，使用基于 LabVIEW 实现的软件环境进行全自动数据采集和数据处理。使用光学混合器可以通过干扰瑞利散射信号和本地振荡器来区分相位、幅度和偏振，并在两个信号之间产生四个 90° 相位步进干涉。