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

摘要

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 CO2 laser 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.

主权项

1. A high stable fiber fabry-perot pressure sensor with glue-free packing, comprising:
(a) a sensor head with a fabry-perot cavity, being a 4-layer structure where a first layer is a silicon wafer for sensing a pressure and has a rear surface forming a first reflecting surface of said fabry-perot cavity, a second layer is a first Pyrex glass wafer shaped as a ring with a through hole, a third layer is a second silicon wafer forming a second reflecting surface of said fabry-perot cavity, and a fourth layer is a second Pyrex glass wafer having a through hole and a rear end face; (b) a sensor body of a cylinder or rectangular shape having a through hole and being made of Pyrex glass or K9 glass, said sensor body having a front end face spliced with said rear end face of said second Pyrex glass wafer; (c) a transmission optical fiber, having a front end face disposed into said through hole of said sensor body for transmitting incident light and emergent light, and said front end face of said transmission optical fiber is in contact with said rear end face of said second silicon wafer; and wherein said four layers of said sensor head bonded to each other by anodic bonding to form bonds which comprise no glue.