A Self-Referencing Intensity-Based Fabry–Perot Cavity for Curvature Measurement

Abstract

In this article, a self-referencing intensity-based fiber optic sensor relying on the principle of Fabry–Perot interference is proposed and demonstrated to measure curvature. The sensor is manufactured producing an air bubble cavity between two sections of multimode fiber. By detecting optical power variations at specific wavelengths, it was possible to measure curvature, enabling this sensor as a self-referencing system. For this setup, the achieved curvature sensitivity was 0.561 ± 0.014 dB/m−1, with a correlation factor up to 0.997, within the measurement range of 0.0–0.8 m−1. The proposed system has several features, including the self-referencing characteristic and its structure simplicity in terms of measuring procedure, making it a useful system.