Microstructured Optical Fiber Based Distributed Sensor for In Vivo Pressure Detection

Microstructured optical fiber based distributed pressure sensor is proposed and demonstrated for high resolution manometry (HRM), which adopts the hybrid wavelength and frequency division multiplexing architecture, and hyperelastic packaging. The microstructure acting as a sensing element is composed of two identical and closely spaced ultrashort fiber Bragg gratings with the reflectivity of only 1%. In theory, 243 microstructures can be multiplexed along one single fiber with an interval of 10 mm beneficial from the compact structure, hybrid encoding feature, and low insertion loss. Homogeneous elastic packaging is explored to protect the fiber and greatly enhance the lateral pressure sensitivity of the sensor. Moreover, a mechanical model is established through the finite element method to analyze the sensitizing effect of the packaging. A prototype system is built and experimentally demonstrated the distributed pressure measurement with the spatial resolution of 10 mm and the pressure sensitivity up to 2.2 Nm/mPa. Due to the advantage of high spatial resolution, high multiplexing capacity, and high pressure sensitivity, the proposed sensor is suitable for HRM in medical application.