Optical glass fibers attenuation

A variety of sources such as bubbles, impurities, density changes, bends, etc. can result in attenuation of the signal in an optical glass fiber as shown in Fig. 

Recently, the fiber-optic probe has been employed frequently in NIR measurement. Many kinds of fiber-optic probes for NIR measurements are commercially available that can be used to perform on-line monitoring in food industries (Fig. 5.9 Ref. 12). However, reasonably priced glass fibers attenuate energy, particularly in the combination band region (1800-2500 nm) because the relatively high OH content of the glass. 

Attenuation. The exceptional transparency, or low attenuation, of siUca-based glass fibers has made them the predominant choice for optical transmission because of the low level of absorption and scattering of light as it traverses the material. Together these comprise optical attenuation, or loss, measured in dB where... 

If double-beam spectrophotometers are used, a 10% Tor 1% T optical attenuator (hole sieve, grey filter, opalescent glass), or preferably the same optical arrangement (fiber optic cable, lenses, adapters, etc.) must be taken. 

Fiber glass-reinforced plastic tanks, 24 299 Fiber grating, 11 150-151 Fiber length (FL), 18 148 Fiber manufacture, sodium bisulfite in, 23 673 Fiber-matrix bonding, 26 771-772 Fiber modification, chemical, 16 14 Fibernodes, 11 595 Fiber-optic probes, 16 524 Fiber optics, 11 128-162, 15 469 attenuation in, 11 132-133 dispersion in, 11 134-135 fiber drawing in, 11 141-145 fiber strength in, 11 141-145 history of, 11 128-131 inside processes for, 11 136-140 near-infrared, 23 141 optical amplifiers with, 11 145-146 optical fiber fabrication for,... 

The development of optical fiber is a fascinating story, especially with regard to the introduction of CVD as the primary method of fabrication, but the details are beyond the scope of this text. Suffice to say that traditional glass-forming technologies, which were based on melt processing, did not provide fibers free from defects such as bubbles or with sufficient purity to prevent enormous attenuation losses. The lowest losses of optical quality glasses were on the order of 1000 dB/km, whereas optical fibers today... 

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