Fiber attenuation

One of the limitations of the curtain/slot draw process is that the amount of fiber attenuation is constrained due to the short distance generally allowed between the spinnerette and the venturi slot and the use of relatively low pressure air for drawing so as not to induce high turbulence in the area of the laydown. In practical terms this has made the process difficult to adapt for the production of polyester fabrics which inherently require much higher fiber acceleration to attain the desired polyester fiber properties. 

To date, the best experimental results in terms of fluoride fiber attenuation is 0.45 0.15 dB km at 2.35 J,m, measured for a 60-m-long ZBLAN fiber. 

Theoretical progress will no doubt be immediately followed by experimental advances. The development of new technologies can extend the limit of secure communication. Mainly detectors in the 1550-nm fiber-optic communication window require a big improvement. Any reduction of the fiber attenuation would also greatly contribute to extending the communication range. 

Fiber attenuation The process for making thin or slender. It applies to the formation of fiber from molten glass. 

Optical fiber attenuation is caused by several factors both internal and external to the fiber. Fiber attenuation resulting from internal sources is referred to as intrinsic attenuation, while that resulting from external sources is referred to as extrinsic attenuation. The specific components of intrinsic and extrinsic attenuation are addressed in greater detail in the next section. 

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. 

In the visible to near-infrared region, the C-D and C-F overtone absorption intensities are several orders of magnitude lower than those of C-H bonds because of the much higher overtone orders. This imphes that fiber attenuation can be significantly reduced by replacing the hydrogen atoms with atoms such as deuterium and fluorine. 

The bandwidth of a fiber determines the maximum transmission data rate or maximum transmission distance. Most common POF (plastic optical fiber) transmission systems adopt on-off keying by direct modulation of the optical source (laser or light-emitting diode). If an input pulse waveform can be detected without distortion at the other end of the fiber, the maximum link length is limited by the fiber attenuation. However, in addition to the optical power attenuation, the output pulse is generally broader in time than the input pulse. This pulse broadening limits the transmission capacity, namely, the bandwidth of the fiber. The bandwidth is determined by the impulse response as follows [1] Optical fibers are usually considered quasi-linear systems thus, the output pulse is described by... 

Attenuation, or transmission loss, is one of the most important performance indicators of optical fibers. Attenuation is the main determinant of the maximum transmission distance of optical communication systems without amphfiers or repeaters, as well as of the maximum output power from the light source and... 

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