Dispersion of Chirped Fiber Bragg Gratings
Chirped fiber Bragg gratings (CFBGs) offer an attractive solution for dispersion management in long haul and high capacity point to point optical links.
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How to measure strain using fiber Bragg gratings
This paper gives a short introduction to FBG sensors, points out their special strengths and weaknesses and describes a measuring system which enables strain gages and FBGS to be measured simultaneously, providing all data processing functions originally developed. The work is devoted to the consideration of methods for determining the strain of objects using fiber Bragg gratings under a high-frequency vibration or pulsed mechanical action, which is difficult to perform using widespread methods and devices. A fiber Bragg grating is a small length of optical fiber that comprises a pattern of many reflection points that creates a reflection of particular wavelengths of incident light.
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Methods for Detecting Stress in Fiber Bragg Gratings
This paper gives a short introduction to FBG sensors, points out their special strengths and weaknesses and describes a measuring system which enables strain gages and FBGS to be measured simultaneously, providing all data processing functions originally developed for the. Fiber Bragg Grating Sensors (FBGS) are gaining increasing attention in the field of experimental stress analysis. They are easy to install, immune to electromagnetic interferences and can also be used in highly explosive atmospheres.
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Classification of Special Fiber Bragg Gratings
Fiber gratings can be classified into short-period fiber Bragg gratings (FBGs) and long-period fiber gratings (LPFGs) based on the size of the refractive index modulation period. FBGs typically have a grating period ranging from hundreds of nanometers to microns. The photosensitivity of optical fibres allows the fabrica-tion of phase structures directly into the fibre core, called fibre Bragg gra -ings (FBG), Fig.
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A slight stress change in the Bragg fiber grating at 6nm
If the strength of the index modulation in a grating is constant over some length, and suddenly drops to zero outside that range, the reflection spectrum exhibits side lobes, in particular if the peak reflectance is high (see Figure 2). Some fiber Bragg gratings are fabricated such that the planes of constant refractive index are not normal to the fiber axis, as usual, but are tilted against the axis by some angle (often a few degrees). If that tilt is strong enough, the coupling to backward core modes may become quite weak; instead, one has a coupling of core modes to cladding mo. As with silica fibers, one usually uses ultraviolet light, but the physical mechanisms are somewhat different.
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