A kind of optical fiber fp air pressure sensor with optical vernier effect and preparation method thereof

Abstract

The invention discloses an optical fiber FP air pressure sensor with optical vernier effect and a preparation method thereof. The sensor comprises a single-mode optical fiber, a quartz capillary and a photonic crystal optical fiber. The two ends of the quartz capillary are respectively connected to the respective ends of the single-mode fiber and the photonic crystal fiber by fusion; the other end of the photonic crystal fiber is directly connected to the outside world, and its hole structure is convenient for the outside gas to enter the fiber optic FP sensor. In the cavity, the quartz capillary and the photonic crystal fiber form two Fabry-Perot resonant cavities with vernier effect. A commercial optical fiber fusion splicer is used for preparation, the discharge time and intensity of the electrodes are well controlled to cascade the two types of optical fibers and the optical fiber is cut using a precision cutting device, and the length of the optical fiber is strictly controlled to produce a vernier effect. The optical fiber FP air pressure sensor of the invention has the advantages of small volume, simple preparation, strong adaptability, high sensitivity and wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing and communication, and in particular relates to an optical fiber FP air pressure sensor with optical cursor effect and a preparation method thereof. Background technique [0002] As a kind of pressure sensor, the air pressure sensor has a wide range of application values ​​in national defense, maritime affairs, aerospace and civil use, and even some smart phones are embedded with air pressure sensors. The fiber optic air pressure sensor based on the Fabry-Perot interferometer (FPI) has attracted the attention of the industry because of its unique advantages. As we all know, optical fiber FPI usually includes a Fabry-Perot cavity composed of an optical fiber end face and a diaphragm end face. When the Fabry-Perot cavity is affected by external air pressure, the cavity of the Fabry-Perot cavity will change. Through The air pressure measurement can be realized by detecting the change o...

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Problems solved by technology

However, the thickness of the thin film coating needs to be precisely controlled, and the thin film deposition layer usually has a columnar crystal structure, which is not resistant to bending, and this technology is time-consuming, and the cost of equipment and instruments is also very expensive

Femtosecond laser micromachining technology can drill holes in the cladding of the quartz capillary, so that the punched air holes are connected to the central air hole to form an FP cavity, and directly punch holes in the core of the single-mode fiber, and then connect with another single-mode fiber. Optical fiber fusion splicing forms a bubble through the arc discharge of the fusion splicer, thereby producing an FP cavity. The preparation process of this method is simple and easy, but the parameters for the femtosecond laser drilling need to be accurately set, and the femtosecond laser is expensive, and the air pressure sensitivity Not high, the maximum sensitivity of the above scheme can only reach 3.592nm / MPa

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