Pressure sensor with large sensing dynamic range based on pressure-induced birefringence in LN crystal

Abstract

In this paper, an optical pressure sensor based on pressure-induced birefringence in Lithium Niobate (LN) crystal is designed to achieve large sensing dynamic range. By using the photo-elastic effect of LN crystal, the optical phase change caused by the external pressure can be converted into the change of the output light intensity. Considerable sensor range can be obtained without special processing of the LN crystal, which makes it have high pressure tolerance. The sensing range of 24.85 MPa is demonstrated to be achievable on x-cut LN crystal with a length of 10 mm in the z-axis direction. The sensing sensitivity can reach 0.281 mW/MPa. By customizing the sensing range, it is expected to use the LN crystal based pressure sensor with the ease of fabrication to monitor high pressure scenarios, such as marine and large buildings monitoring.