Optical fiber FP (Fabry-Perot) gas pressure sensor with optical vernier effect as well as preparation method thereof

Abstract

The invention discloses an optical fiber FP (Fabry-Perot) gas pressure sensor with optical vernier effect as well as a preparation method thereof. The sensor comprises single-mode optical fiber, a quartz capillary and photonic crystal optical fiber. The two ends of the quartz capillary are connected one end of the single-mode optical fiber and one end of the photonic crystal optical fiber correspondingly by a fusion welding mode; and the other end of the photonic crystal optical fiber is directly connected with the outside, and the pore structure facilitates the outside gas to enter a cavity of an optical fiber FP sensor, so that the quartz capillary and the photonic crystal optical fiber form two Fabry-Perot resonant cavities with vernier effect. During preparation, a commercial optical fiber fusion splicer is used, the discharging time and the discharging intensity of the electrode are controlled, two types of optical fiber are cascaded, a precise cutting device is used for cutting the optical fiber, and the length of the optical fiber is strictly controlled, so that the vernier effect is generated. The optical fiber FP gas pressure sensor is small in volume, simple and convenient to prepare, high in adaptability and high in sensitivity, and has wide application prospect.

Description

Technical field [0001] The invention belongs to the technical field of optical fiber sensing and communication, and specifically relates to an optical fiber FP air pressure sensor with optical vernier effect and a preparation method thereof. Background technique [0002] As a type of pressure sensor, air pressure sensors have wide application value in national defense, maritime affairs, aerospace, and civilian applications. Even some smart phones have air pressure sensors embedded in them. The optical fiber air pressure sensor based on Fabry-Perot interferometer (FPI) has attracted much attention in 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 acted upon by external air pressure, the cavity of the Fabry-Perot cavity will change. By detecting changes in the interference spectrum of reflected light caused by c...

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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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