Fiber optic sensors work by using light to measure changes in the properties of an optical fiber. The basic principle behind fiber optic sensing is that changes in the environment around the fiber can cause changes in the way light travels through it. These changes can then be detected and used to measure various physical quantities, such as temperature, pressure, strain, or chemical composition.
There are several types of fiber optic sensors, but the most common ones are based on the phenomenon of "optical interference". These sensors use a fiber optic cable that is made up of a core (where the light travels) and a cladding (which surrounds the core and reflects the light back into it). By introducing a disturbance into the fiber, such as a change in temperature or pressure, the light that travels through the fiber can be affected, causing interference patterns that can be detected and analyzed.
One of the most common types of fiber optic sensors is the Bragg grating sensor, which uses a periodic pattern of refractive index changes within the fiber to reflect certain wavelengths of light back towards the source. By measuring the wavelength of the reflected light, the strain or temperature of the fiber can be determined.
Another type of fiber optic sensor is the Fabry-Perot interferometer, which uses a cavity formed by two partially reflecting mirrors to generate interference patterns that can be used to measure physical quantities.
Fiber optic sensors are used in a wide range of applications, including structural health monitoring, oil and gas exploration, medical sensing, and environmental monitoring, among others. They offer several advantages over traditional sensors, including high sensitivity, immunity to electromagnetic interference, and the ability to operate in harsh or hazardous environments.
