Optical fibers are very thin, flexible glass or plastic strands along which large quantities of information can be transmitted in the form of light pulses. They are not subject to electromagnetic interference and they need to retransmit signals.
Types
There are two types of optical fibers: single-mode and multi-mode. Single-mode fibers support a single propagation path of light pulses through them. Multimode fibers are larger in diameter and support many propagation paths of light pulses through them.
Material Composition
Optical fibers can be manufactured from transparent plastics or glasses. Glass optical fibers are usually made with silica, though a few other materials, such as chalcogenide, fluorozirconate or fluoroaluminate glasses can be employed for long-wavelength infrared uses. Like other glasses, these glasses have a refractive index of about 1.5.
Plastic optical fibers have a core diameter of 0.5 millimeters or larger. They typically have higher attenuation coefficients than glass fibers and this high attenuation limits the range of the systems that employ them.
Applications
Optical fibers can be used as optimal means for communication and networking since they are flexible and can be packaged in the form of bundles of cables. They are especially useful for long-distance communications, since light signals propagate through these fibers with little attenuation as compared to electrical cables. This allows long distances to be spanned before signals need to be regenerated through expensive repeaters.
Optical fibers can also be utilized as sensors to gauge pressure, tension, temperature and other similar quantities by altering them so that the quantity being measured changes the intensity, wavelength, phase or polarization of light pulses in the fiber.
Optical fibers can also be employed for illumination purposes. They can be utilized as light conductors in medical applications, which require a bright light to be shown on a body organ that does not have a clear line-of-sight pathway. Moreover, optical fibers can be used to supply sunlight from the roof to various parts of a building in badly illuminated constructions. Optical fiber illumination can also be employed for decorative purposes, such as signs, works of art or Christmas trees.
Optical fibers can also be used in imaging optics applications. A coherent pack of fibers can be utilized, in a long, slender imaging device, known as endoscope, to view objects through a small hole. Medical endoscopes are employed for minimal invasive surgical procedures (called endoscopy). Industrial endoscopes find application in the inspection of difficult to reach areas, such as jet engine interiors.
Optical fibers can be utilized to supply low power (about one watt) to electronic equipment located in difficult electrical environments. This application can find usage in high-power antenna electronics and measurement appliances fitted in high voltage transmission devices.
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