Pressure vector sensor based on an orthogonal optical path Sagnac interferometer

Opt Express. 2020 Mar 16;28(6):7969-7979. doi: 10.1364/OE.388821.

Abstract

A novel pressure vector sensor based on a short section of PANDA fiber with an orthogonal optical path Sagnac interferometer structure is proposed and experimentally demonstrated. The sensor structure was realized using a gold film, coated on the end of the fiber tip through the magnetron sputtering method. The birefringence-dependent interference dip is sensitive to external force. Therefore, pressure can be monitored by this sensor. The relationship between the force direction and the pressure sensitivity was studied. We embedded the sensor in aluminum, using ultrasonic consolidation technology, to investigate the application of its sensing properties in metal. Based on this, the influence of the embedding direction on the polarization characteristics of the fiber was analyzed. The experimental results showed that the sensor offered a high sensitivity of 2330 pm/(N·m) in its freeform and 780 pm/(N·m) after being embedded in aluminum. Due to its simple fabrication process, low cost, and high sensitivity, the pressure sensor described in this paper could be a competitive candidate in several pressure sensing applications.