FP pressure sensor based on low-temperature coupling effect of photonic crystal fiber

Abstract

The invention discloses an FP pressure sensor based on a low-temperature coupling effect of a photonic crystal fiber. The FP pressure sensor comprises the photonic crystal fiber, a quartz capillary tube and a polymer film, the welding surface of the photonic crystal fiber and the quartz capillary tube and the inner surface of the polymer film form two parallel reflecting surfaces of an FP interferometer. When light in the photonic crystal fiber encounters the two reflecting surfaces, reflected light is generated, the two beams of reflected light interfere in the photonic crystal fiber to generate an interference spectrum, when the cavity length of the FP interferometer changes along with the measured pressure, the changing optical path difference between the two beams of reflected light causes the movement of the interference spectrum, and by detecting the movement amount of the interference spectrum, the change of the measured pressure is obtained. The FP pressure sensor is suitable for measuring the conditions that the environment temperature change is large, the temperature change needs to be compensated, and the measured water pressure is small, meanwhile, the requirement for high precision is met, the manufacturing process is simple, and the size is small.

Description

technical field [0001] The invention belongs to the technical field of optical FP interferometers, in particular to an FP (Fabry-Perot) pressure sensor based on the low-temperature coupling effect of photonic crystal fibers. Background technique [0002] FP interferometers are widely used in many fields such as oil exploration, medical treatment, and aviation. According to their structure, they are mainly divided into two types: intrinsic type and extrinsic type. For intrinsic optical fiber sensors, the medium in the cavity is the optical fiber itself, which has the advantage of low loss, but the refractive index of the medium is greatly affected by external factors, so it is not easy to separate the influence of temperature when measuring pressure, and the temperature cross-coupling effect obvious. The extrinsic fiber optic sensor uses the extrinsic FP sensing head as the sensor detection element, and the medium in the cavity is generally air. By selecting appropriate para...

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Problems solved by technology

[0003] However, the existing FP interferometer-based pressure sensor has many defects such as complex structure, large volume, and high manufacturing cost. Inaccurate, low pressure measurement accuracy

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