High stable fiber fabry-perot pressure sensor with glue-free packing and its fabrication method

Abstract

The present invention relates to a high stable fiber fabry-perot pressure sensor with glue-free packing and its fabrication method. The sensor includes a sensor head, a sensor body with a through-hole in the axial direction and a optical fiber. The sensor head is a 4-layer structure, which includes the first silicon wafer, the first Pyrex glass wafer, the second silicon wafer and the second Pyrex glass wafer. The rear surface of the first silicon wafer forms the first reflecting surface of the fabry-perot (F-P) cavity, and the second silicon wafer provides the second reflecting surface for the F-P cavity. The second Pyrex glass wafer is welded together with the sensor body. The optical fiber is fixed in the sensor body by a COlaser welding to achieve the glue-free packing. When the external pressure is applied to deform the first layer silicon wafer, the F-P cavity length will change. When a broad band source is used, the variation of the cavity length can be obtained by collecting the reflection spectrum or low-coherence interference fringe of the sensor, thus the pressure information can be obtained. The structure of the invention can effectively eliminate the affect of environmental factors, such as temperature and humidity, and greatly promoting the measuring accuracy.