Study on the stabilization of an optical fiber interferometric sensor

Abstract

Optical fiber interferometric (OFI) sensors have been extensively used to measure a large variety of parameters due to their superior performance. The F-P OFI sensors are very sensitive to the cavity-length changes. However, it is difficult to fix the operating position at the quadrature point (Q point) in the sensor fabrication, and the sensor may also encounter with various environmental perturbations, which may drive the sensors out of the linear region. For the purpose of developing a highly-sensitive and reliable OFI vibration sensor, a new method was proposed and demonstrated in our research. By choosing a short cavity length, we can obtain OFI sensor with large interference period, which is helpful to avoid the infection of Q point drifting, but the visibility decline problem will arise simultaneously. A tilted diaphragm method was used to solve this problem in the short cavity length. Theoretical analyses have been performed, and a tilted diaphragm optical fiber sensor has been fabricated, the result shows a visibility of nearly 100% is realized in a short cavity about 50μm.