High-sensitivity optical fiber temperature sensor

Abstract

The invention discloses a high-sensitivity optical fiber temperature sensor. The high-sensitivity optical fiber temperature sensor comprises a leading-in optical fiber, a capillary collimator and an optical sheet, wherein the optical sheet is directly connected with the capillary collimator, the leading-in optical fiber is inserted into the capillary collimator and connected with the capillary collimator, an F-P cavity is formed by two end faces of the optical sheet, and the leading-in optical fiber and the optical sheet form the F-P cavity. The leading-in optical fiber is used for leading inlight source signals and transmitting reflected light. When the temperature is changed, the capillary collimator and the optical sheet are subjected to thermal expansion, so that the two F-P cavitiesare changed to cause the change of the spectrum, and the ultrahigh temperature sensitivity is obtained. Besides, the optical thin sheet and the capillary collimator are low in cost and simple to manufacture, a complex manufacturing process and expensive equipment are not needed, and the preparation cost of the sensor can be reduced.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensor manufacturing, in particular to a high-sensitivity optical fiber temperature sensor. Background technique [0002] The advantages of optical fiber sensors, such as high sensitivity, anti-electromagnetic interference, good reliability, and abundant raw materials, have attracted widespread attention. Common fiber optic sensors include fiber gratings, fiber Sagnac interferometers, fiber Mach-Zehnder interferometers (MZI), and fiber Fabry–Perot resonators. Among them, the vernier effect produced by the fiber optic Fabry-Perot resonator can be used to amplify the sensitivity of the sensor, so it has received extensive attention. For example, in 2009, Dai and Jin et al proposed a vernier effect optical sensor based on a series optical fiber structure, using the wavelength demodulation method to achieve ultra-high sensitivity measurement of the refractive index. In 2014, Zhang et al. propo...

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Problems solved by technology

In 2014, Zhang et al. proposed to use the large mode field characteristics of the hollow-core photonic crystal fiber (HC-PCF) to embed two sections of HC-PCF into the single-mode fiber (SMF) to form a cascaded FPI structure of the vernier effect optical fiber sensor, which is applied to stress and Compared with a single FPI, the sensitivity of the magnetic field measurement is increased by about 29 times. In 2015, Shao et al. proposed a vernier-effect optical fiber temperature sensor with a Sagnac interferometer in series, and its sensitivity was increased by about 9 times compared with a single Sagnac interferometer. The entire sensor is large in size (the length of a single Sagnac interference ring is about 2m), and it is difficult to achieve high spatial resolution temperature measurement

However, the materials and equipment required by the above-mentioned sensors are relatively expensive, and the production process is relatively complicated, which is not conducive to the mass production of sensors.

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