Research on Temperature-Insensitive Micro-Displacement Sensor Cascaded With Spherical Structure

A temperature-insensitive micro-displacement optical fiber sensor is presented. The sensor is composed of a section of spindle-shaped SMF cascaded with two spherical structures. The sensor characteristics are enhanced by utilizing the bending action of the spindle-shaped structure and the coupling action of the spherical structure. In this experiment, the sensing characteristics of micro-displacement and temperature were analyzed by comparing three sensors with different horizontal diameters. The experimental results show that the micro-displacement sensitivity of the sensor is -521 pm/
$\mu \text{m}$
when micro-displacement varies from
$0~\mu \text{m}$
to
$40~\mu \text{m}$
at a horizontal diameter of 4.0 mm. The sensors are not sensitive to temperature in the range of 20-60°. Furthermore, the sensors have the advantages of simple structure, low cost, small volume, easy fabrication and good stability, which is more favorable to promote the application in industrial fields where highly precise control of manufacturing processes is required.