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বোয়িং ৭৬৭ এর অপটিক্যাল গাইরোস্কোপ সেন্সর হিসেবেও অপটিক্যাল ফাইবার ব্যবহৃত হচ্ছে। কোন কোন গাড়ীতেও আজকাল অপটিক্যাল ফাইবার ব্যবহৃত হচ্ছে।
== অপটিক্যাল ফাইবারের অন্যান্য ব্যবহার ==
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Fibers are widely used in illumination applications. They are used as [[light guide]]s in medical and other applications where bright light needs to be brought to bear on a target without a clear line-of-sight path. In some buildings, optical fibers are used to route sunlight from the roof to other parts of the building (see [[non-imaging optics]]). Optical fiber illumination is also used for [[Decoration|decorative]] applications, including [[Commercial signage|sign]]s, [[art]], and artificial [[Christmas tree]]s. [[Swarovski]] boutiques use optical fibers to illuminate their crystal showcases from many different angles while only employing one light source.
Optical fiber is also used in imaging optics. A coherent bundle of fibers is used, sometimes along with lenses, for a long, thin imaging device called an endoscope, which is used to view objects through a small hole. Medical endoscopes are used for minimally invasive exploratory or surgical procedures ([[endoscopy]]). Industrial endoscopes (see [[fiberscope]] or [[borescope]]) are used for inspecting anything hard to reach, such as jet engine interiors.
An optical fiber [[dopant|doped]] with certain rare-earth elements can be used as the gain medium of a [[laser]] or [[optical amplifier]].
[[Plastic optical fiber]] is commonly used as a [[digital audio]] cable, to connect digital sources to digital [[Receiver (radio)|receiver]]s. The most common format is [[TOSLINK]].
Optical fibers doped with a [[wavelength shifter]] are used to collect [[scintillator|scintillation]] light in [[physics]] experiments.
Optical fiber can be used to supply a low level of power (around one watt) to electronics situated in a difficult electrical environment. Examples of this are electronics in high-powered antenna elements and measurement devices used in high voltage transmission equipment.
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<big>বড় লেখা</big>== গঠন ==
* বুলেটকৃত তালিকা আইটেম
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Optical fiber is made by first constructing a large-diameter ''preform'', with a carefully controlled refractive index profile, and then ''pulling'' the preform to form the long, thin optical fiber. The preform is commonly made by three [[chemical vapor deposition]] methods: ''inside vapor deposition'', ''outside vapor deposition'', and ''vapor axial deposition''.
With ''inside vapor deposition'', a hollow glass tube approximately 40 cm in length known as a "preform" is placed horizontally and rotated slowly on a lathe, and gases such as [[silicon tetrachloride]] (SiCl<sub>4</sub>) or [[germanium tetrachloride]] (GeCl<sub>4</sub>) are injected with [[oxygen]] in the end of the tube. The gases are then heated by means of an external hydrogen burner, bringing the temperature of the gas up to 1900 [[kelvin]]s, where the tetrachlorides react with oxygen to produce [[silica]] or germania ([[germanium]] [[oxide]]) particles. When the reaction conditions are chosen to allow this reaction to occur in the gas phase throughout the tube volume, in contrast to earlier techniques where the reaction occurred only on the glass surface, this technique is called ''modified chemical vapor deposition''.
The oxide particles then agglomerate to form large particle chains, which subsequently deposit on the walls of the tube as soot. The deposition is due to the large difference in temperature between the gas core and the wall causing the gas to push the particles outwards (this is known as thermophoresis). The torch is then traversed up and down the length of the tube to deposit the material evenly. After the torch has reached the end of the tube, it is then brought back to the beginning of the tube and the deposited particles are then melted to form a solid layer. This process is repeated until a sufficient amount of material has been deposited. For each layer the composition can be varied by varying the gas composition, resulting in precise control of the finished fiber's optical properties.
In outside vapor deposition or vapor axial deposition, the glass is formed by ''flame hydrolysis'', a reaction in which silicon tetrachloride and germanium tetrachloride are oxidized by reaction with water (H<sub>2</sub>O) in an [[oxyhydrogen flame]]. In outside vapor deposition the glass is deposited onto a solid rod, which is removed before further processing. In vapor axial deposition, a short ''seed rod'' is used, and a porous preform, whose length is not limited by the size of the source rod, is built up on its end. The porous preform is consolidated into a transparent, solid perform by heating to about 1800 kelvins.
The preform, however constructed, is then placed in a device known as a ''drawing tower'', where the preform tip is heated and the optic fiber is pulled out as a string. By measuring the resultant fiber width, the tension on the fiber can be controlled to maintain the fiber thickness.
This manufacturing process is accomplished by several fiber optic companies, including [[3M]], [[Corning Inc.]], and [[Molex]]. In addition, various fiber optic component manufacturers, assembly houses, and custom fiber optic providers exist.
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== অপটিক্যাল ফাইবার কেবলস ==
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