ABSTRACT
The laser invention in the 1960s and the advances toward low-loss optical fiber in the 1970s stimulated further scientific advances, both in telecommunications and in optical fiber sensors. The research on optical fiber sensors produced and continues to give life to a variety of measurement techniques for different applications, competing with traditional sensing methods, mainly in niche areas, from the airspace to the medical industry. Optical fiber sensors operate by modifying one or more properties of the light passing through the sensor, when the parameter to be measured changes. Intensity-based sensors offer the advantages of ease of fabrication, low price-performance ratio, and the simplicity of signal processing. Several mechanisms in an optical fiber weaken the propagated signal, such as absorption and diffusion by impurities, Rayleigh scattering, ultraviolet and infrared absorption, and microbending and macrobending. For many applications, spectroscopic detection has been a reliable method for the design of fiber optic sensors and is used for chemical, biological, and biochemical sensing.
