Internet of Things Infrastructure Based on Fast, High Spatial Resolution, and Wide Measurement Range Distributed Optic-Fiber Sensors

Information sensor can realize the ubiquitous connection between objects and humans by the distributed fiber-optic sensor array, i.e., emerging infrastructure for Internet of Things, in which optical frequency domain reflectometry (OFDR) with its high spatial resolution plays an important role in achieving intelligent perception and identification of the objects. However, given a certain fiber length, there are tradeoffs among the processing speed, the spatial resolution, and the strain measurement range. In this article, a time optimization interpolation method and a distance domain compensation method are reported and experimentally verified to break the aforementioned tradeoffs for the first time. First, a full theoretical analysis on how to reduce the interpolation number and the reason why it is difficult to achieve high spatial resolution and large strain measurement and how to resolve it is made. Second in the proof-of-concept experiment, measurements of large strains up to 10 000 $\boldsymbol{\mu } \boldsymbol{\varepsilon }$ are realized along the sensing fiber with a spatial resolution of 2 mm using a conventional OFDR system. Also, the processing time is shortened by 76 times compared with the traditional processing method. This article makes a significant step toward high-performance OFDR system with fast processing, high spatial resolution, and wide strain measurement.