Vacuum packaged graphene resonant optical fiber pressure sensor and manufacturing method thereof

Abstract

The invention discloses a vacuum packaged graphene resonant optical fiber pressure sensor. The sensor comprises a silicon pressure sensitive unit (1), a graphene film (2), a clamping piece (3), a glass sealing cover (4), an insertion core (5) and an optical fiber (6). According to the sensor, the vacuum packaged graphene film is taken as a resonance element; and the deflection deformation of the graphene film is detected based on a Fabry-Perot interference principle by performing photo-thermal excitation on the suspended graphene film. A main body of the silicon pressure sensing unit is a pressure sensing silicon film, a blind hole structure is manufactured on the upper surface of the silicon film, and the periphery of the graphene film is fixedly supported on the blind hole in the upper surface of the silicon film through the clamping piece. External measured pressure directly acts on the pressure sensing silicon film to generate strain, so that the rigidity of the graphene film above the silicon film is changed, the resonant frequency of graphene is further changed, and pressure measurement is realized by demodulating the change of the resonant frequency. The pressure sensor is miniaturized in size, wide in measurement range, good in stability, high in sensitivity and resistant to electromagnetic interference.

Description

technical field [0001] The invention relates to the technical field of resonators and optical fiber sensing, in particular to a vacuum-packaged graphene resonant optical fiber pressure sensor and a manufacturing method thereof. Background technique [0002] The resonant sensor is a high-performance sensor that obtains the measured changes by measuring the resonance characteristics of the resonant element. It has excellent resolution, stability and repeatability, and the output of the sensor is a periodic quasi-digital signal. The micromechanical resonant pressure sensor is based on the traditional pressure measurement principle. The pressure is converted into strain through the pressure sensitive unit, which causes the resonance characteristic of the resonant sensitive element to change, thereby measuring the pressure. Compared with traditional pressure sensors, it has the characteristics of miniaturization, low energy consumption, digital output, and high resolution. At pr...

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Problems solved by technology

In 2014, Jun Ma of the Hong Kong Polytechnic University and others produced a fiber-optic graphene resonator, and carried out experiments on the influence of different pressures on the frequency of the beam-type resonator, and applied for a patent (CN103994851), but the graphene film is directly sensitive to the Measuring pressure, in direct contact with the measured medium, resulting in stability and reliability can not be guaranteed

In 2016, Dolleman et al. from Delft University of Technology in the Netherlands reported a dumbbell-shaped graphene resonant pressure sensor, which achieved ultra-high pressure sensitivity (9kHz / mbar), but because the sensitive membrane is directly exposed to the measured environment , still has the disadvantages of small measurement range, poor stability, and low Q value

[0004] In general, the existing literature and patents do not involve high-performance graphene resonant pressure sensors for fiber excitation / vibration pickup. The main reason is that graphene is directly exposed to the measured environment, and the quality factor is affected by the pressure of the measured environment, resulting The stability of the graphene resonant state is poor, which is also a common problem in the research of graphene resonant pressure sensors.

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