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A fiber Bragg grating (FBG) is a type of distributed Bragg reflector constructed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all others. This is achieved by creating a periodic variation in the refractive index of the fiber core, which generates a wavelength-specific dielectric mirror .
Fiber-optic sensors are used in electrical switchgear to transmit light from an electrical arc flash to a digital protective relay to enable fast tripping of a breaker to reduce the energy in the arc blast. [18] Fiber Bragg grating based fiber-optic sensors significantly enhance performance, efficiency and safety in several industries.
An addressed fiber Bragg structure can perform triple function in fiber-optic sensor systems: a sensor, a shaper of double-frequency probing radiation, and a multiplexor. The key feature of AFBS is that it enables the definition of its central wavelength without scanning its spectral response, as opposed to conventional fiber Bragg gratings ...
Time-resolved simulation of a pulse reflecting from a Bragg mirror. A distributed Bragg reflector (DBR) is a reflector used in waveguides, such as optical fibers.It is a structure formed from multiple layers of alternating materials with different refractive index, or by periodic variation of some characteristic (such as height) of a dielectric waveguide, resulting in periodic variation in the ...
These developments have allowed POF grating sensors to be used outside the laboratory for the first time. [16] Wavelength multiplexed polymer fiber Bragg gratings - once the fiber connection issue was solved it was possible to fabricated the first ever wavelength division multiplexed (WDM) Bragg grating sensors in polymer optical fibre (POF).
A principle of operation of these sensors is based on the chemical modulation of a hydrogel film volume that incorporates a Bragg grating. As the hydrogel swells or shrinks upon chemical stimulation, the Bragg grating changes color and diffracts light at different wavelengths. The diffracted light can be correlated with the concentration of a ...
An acousto-optic modulator (AOM), also called a Bragg cell or an acousto-optic deflector (AOD), uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency). They are used in lasers for Q-switching, telecommunications for signal modulation, and in spectroscopy for frequency control.
Distributed temperature sensing systems (DTS) are optoelectronic devices which measure temperatures by means of optical fibres functioning as linear sensors. Temperatures are recorded along the optical sensor cable, thus not at points, but as a continuous profile. A high accuracy of temperature determination is achieved over great distances.