Fiber Grating Sensor is a kind of optical fiber sensor. The sensing process based on fiber grating is to obtain sensing information by modulating the fiber Bragg wavelength by external physical parameters. It is a wavelength modulated optical fiber sensor.
Wide-spectrum light source (such as SLED or ASE) will inject light with a certain bandwidth into the fiber grating through the circulator. Due to the wavelength selectivity of the fiber grating, the qualified light will be reflected back, and then sent to the demodulation device through the circulator to measure the reflected wavelength change of the fiber grating. When the fiber grating is used as a probe to measure the external temperature, pressure or stress, the grating pitch changes, which leads to the change of reflected wavelength. The demodulation device deduces the external temperature or strain by detecting the change of wavelength.
(1) Anti-electromagnetic interference: Generally, the frequency of electromagnetic radiation is much lower than that of light wave, so the optical signal transmitted in optical fiber is not affected by electromagnetic interference.
(2) Good electrical insulation, safety and reliability: the optical fiber itself is made of dielectric and does not need to be driven by power supply, so it is suitable for use in inflammable and explosive oil, gas and chemical production.
(3) Corrosion resistance and stable chemical performance: Because the material of optical fiber-Shi Ying has extremely high chemical stability, the optical fiber sensor is suitable for use in harsh environment.
(4) Small volume, light weight and plastic geometry.
(5) Low transmission loss: remote monitoring can be realized.
(6) Large transmission capacity: multi-point distributed measurement can be realized.
(7) Wide measuring range: it can measure temperature, pressure, strain, stress, liquid level, displacement, acceleration, etc.
Fiber Bragg grating sensors are widely used in long-term monitoring by virtue of their own advantages. At present, the development of optical fiber sensor technology is becoming more and more mature, with a wide range of applications. Many applications in various fields show a booming trend, and it is very likely to replace traditional sensors. In the aspect of optical fiber sensing, fiber grating technology has opened up a new field for the development of optical fiber sensing technology. Fiber grating sensor has the advantages of light weight, small size, high sensitivity, corrosion resistance and electromagnetic interference resistance, and good long-term stability and durability. It is precisely because of the above advantages that fiber grating sensors have broad application prospects and practical significance in long-term monitoring projects.