What is the working principle of fiber optic grating pressure sensors

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What is a fiber optic pressure sensor

As a type of fiber optic sensor, pressure sensor is widely used in the measurement of stress such as intelligent robot fingers, vehicle gravity, static surface water pressure, and surface tension of devices due to its simple principle, strong resistance to electromagnetic interference, and resistance to corrosion. At present, pressure sensors mainly use ordinary single-mode optical fibers, polarization maintaining optical fibers, microstructure optical fibers, and other optical fibers based on the principle of total internal reflection of optical fibers for guiding light. By engraving various periods of Bragg gratings inside the optical fibers to detect external loads, a lateral pressure sensor is formed. FJINNO provides fiber optic sensors, fiber optic grating sensors, and fluorescent fiber optic sensors at reasonable prices. Welcome to contact us!

FBG fiber Bragg grating is achieved by introducing periodic refractive index changes in the fiber core area through ultraviolet laser irradiation. When the refractive index variation period of the single-mode fiber core is small, it can couple the forward transmission fundamental mode with the backward transmission fundamental mode and transfer most of the power. This type of fiber grating is called fiber Bragg grating, FBG grating, and the wavelength of light that satisfies this energy conversion or resonance is called the Bragg wavelength of fiber Bragg grating, or the center wavelength of fiber Bragg grating.

Traditional gas or liquid pressure measurement devices are achieved by changing the shape of elastic elements when pressure changes, driving the relevant pointers to rotate, or causing changes in the output of electronic strain sensors installed on them. By rotating the pointer, the pressure can only be roughly read, and the pressure value cannot be collected and transmitted; Electronic pressure sensor signals require corresponding circuit acquisition and transmission. In certain situations where power supply cannot be guaranteed, environmental electromagnetic interference is large, there are numerous sensors with complex wiring, flammable and explosive environments, and signal transmission distances are long, electronic pressure sensors face significant difficulties in practical applications.

Advantages of Fiber Bragg Grating Pressure Sensors

Fluid pressure sensors are widely used sensors, such as bridges, dams, hydrology, tunnels, chemical engineering, meteorology, slopes, etc. They are commonly used sensing elements for detection or monitoring. Due to temperature interference, electromagnetic interference, safety, long-distance transmission, service life, reliability, and other reasons, various existing detection solutions cannot effectively solve the pressure detection problems in this series of industries. Fiber optic grating pressure sensors can solve the problems caused by temperature interference, electromagnetic interference, safety, long-distance transmission, service life, reliability, and other factors in current detection solutions. The pressure monitoring in existing technologies usually uses mechanical pressure sensors and electrical pressure sensors. Mechanical pressure sensors cannot achieve online monitoring, while electrical pressure sensors have the risk of short circuits due to the need for wires to transmit data. The monitoring and fiber optic signal transmission of fiber optic grating pressure sensors are non electric and have no electromagnetic interference. Compared with mechanical and electrical pressure sensors in existing technologies, they have excellent insulation performance measurement, high accuracy, and strong resistance to electromagnetic interference.

The characteristics of fiber optic sensors

Fiber optic sensors have advantages such as no need for power supply to the sensing head, no interference from environmental electromagnetic waves, multiple sensors can be multiplexed in series through a single fiber optic, the sensing head does not generate electrical sparks, and is absolutely safe for long-distance transmission. They have significant advantages in certain environmental applications.

The working principle of fiber optic grating pressure sensor

Fiber optic grating sensor is a type of fiber optic sensor, which is a wavelength modulated fiber optic sensor. Fiber Bragg grating sensors obtain sensing information through modulation of fiber Bragg wavelength by external physical parameters. Compared to electronic sensors, fiber optic grating sensors are more suitable for use in harsh environments such as oil, gas, petrochemical industry, or high temperature and pressure.

Install fiber optic gratings in mechanical structures that can generate displacement or strain under pressure. When the pressure changes, the mechanical structure changes, causing changes in the strain of the fiber optic grating, resulting in changes in the period and center wavelength of the fiber optic grating. Due to the small transmission loss of light waves in the fiber optic, sensors can be connected to wavelength change detection instruments (demodulators) through long (several kilometers or longer) optical fibers to achieve long-distance sensing and measurement.

FJINNO is committed to the research and development of fiber optic grating pressure sensors. Fiber optic grating pressure sensors are widely used in dams, slopes, tunnels, pit foundations. Fiber optic grating pressure sensors can be installed once and used for a long time; Remote monitoring, maintenance free.