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 sensor head: The sensor head is a 4-layer structure. The first layer is the first silicon wafer, which is used as an elastic diaphragm for sensing the pressure. The rear surface of the first silicon wafer forms the first reflecting surface of the fabry-perot(F-P) cavity. The second layer is the first Pyrex glass wafer which has been shaped as a ring with a through hole in the axis; the thickness of the first Pyrex glass wafer determines the original length of the F-P cavity. The third layer is the second silicon wafer which is used to form the second reflecting surface of the F-P cavity. The forth layer is the second Pyrex glass wafer, of which a through hole is processed in the axial direction for locating the position of the front end of the transmission optical fiber. A sensor body: The sensor body is shaped as a cylinder or rectangular to be used for the supporting structure of the sensor and the containing structure of the transmission optical fiber. The middle part of the sensor body is processed a through hole in an axial direction; and the sensor body is made of Pyrex glass or K9 glass. The front end face of the sensor body is spliced with the rear end face of the second Pyrex glass wafer. A transmission optical fiber: The transmission optical fiber travels through the through hole which is in the middle of the sensor body in the axial direction; the transmission optical fiber is used for transmitting incident light and emergent light by arranging the front end of the transmission optical fiber in the through hole which is located in the middle of the second Pyrex glass wafer, and arranging the front end face of the transmission fiber being closely contacted together with the rear end face of the second silicon wafer. The types of the transmission optical fiber include single mode optical fiber and multimode optical fiber.