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{{short description|Light-conducting fiber}}{{рут}}
[[Датотека:Fibreoptic.jpg|мини|200п|''Више оптичких влакана које чине језгро оптичког кабла'']]
[[Датотека:Fibreoptic.jpg|мини|300п|''Више оптичких влакана које чине језгро оптичког кабла'']]
'''Оптичко влакно''' је врста [[Оптички таласовод|оптичког таласовода]] радијалне симетрије, која „вођење“ електромагнетског таласа заснива на ефекту [[тотална унутрашња рефлексија|тоталне унутрашње рефлексије]]. Влакно микрометарских димензија, израђено од стакла или пластике, служи као медијум у [[Фибер оптички кабл|оптичком каблу]] за пренос информација помоћу светлости. Влакна имају концентричну слојевиту структуру. У средини се налази језгро, које води светлост, окружено са омотачем (јакном) са нешто нижим индексом преламања и заштитним слојем пластике.
[[Датотека:Stealth Fiber Crew installing fiber cable underneath the streets of Manhattan.jpg|thumb|250п|Инсталерска екипа ради на постављању оптичког кабла са 432 влакна испод улица Менхетна, Њујорк Сити]]
[[Датотека:Fiber optic illuminated.jpg|thumb|250п|[[TOSLINK]] фибер оптички аудио кабл чији један крај је обасјан црвеним светлом преноси светло на други крај]]
[[Датотека:Optical-fibre-junction-box.jpg|thumb|right|250п|[[19-inch rack|Зидни ормар]] који садржи међусобне везе оптичких влакана. Жути каблови су [[single-mode optical fiber|једносмерна влакна]]; наранџасти и аква каблови су [[Multi-mode optical fiber|вишемодна влакна]]: 50/125 -{µm OM2}- и 50/125 -{µm OM3}- влакна.]]


У зависности од примене, пречник језгра је у распону од неколико до више стотина микрона. А од дијаметра и профила индекса преламања између језгра и омотача, зависи број режима (модова) способних да пропагирају кроз влакно. Оптичка влакана могу бити мономодна (једнорежимска) и мултимодна (вишережимска). Кроз једнорежимска се простире само један мод ласерске светлости и оваква влакна се користе за пренос информација на веће удаљености, док се кроз вишережимска влакна простире више модова и ова влакна се користе за приступне мреже. Овакав пренос информација је бржи, поузданији и сигурнији од преноса бакарним кабловима.
'''Оптичко влакно''' је врста [[Оптички таласовод|оптичког таласовода]] радијалне симетрије, која „вођење“ електромагнетског таласа заснива на ефекту [[тотална унутрашња рефлексија|тоталне унутрашње рефлексије]]. flexible, [[transparency and translucency|Транспарентно]] [[Влакна|влакно]] микрометарских димензија, израђено од [[стакло|стакла]] или [[пластика|пластике]], служи као медијум у [[Фибер оптички кабл|оптичком каблу]] за пренос информација помоћу светлости.<ref>{{cite web|title=Optical Fiber|url=http://www.thefoa.org/tech/ref/basic/fiber.html|website=www.thefoa.org |publisher=[[The Fiber Optic Association]] |access-date=17 April 2015}}</ref> Влакна имају концентричну слојевиту структуру. У средини се налази језгро, које води светлост, окружено са омотачем (јакном) са нешто нижим индексом преламања и заштитним слојем пластике. У зависности од примене, пречник језгра је у распону од неколико до више стотина микрона. А од дијаметра и профила индекса преламања између језгра и омотача, зависи број режима (модова) способних да пропагирају кроз влакно. Оптичка влакана могу бити мономодна (једнорежимска) и мултимодна (вишережимска). Кроз једнорежимска се простире само један мод ласерске светлости и оваква влакна се користе за пренос информација на веће удаљености, док се кроз вишережимска влакна простире више модова и ова влакна се користе за приступне мреже. Овакав пренос информација је бржи, поузданији и сигурнији од преноса бакарним кабловима.

Optical fibers are used most often as a means to transmit light{{efn| [[Infrared light]] is used in optical-fiber communication due to its lower attenuation}} between the two ends of the fiber and find wide usage in [[fiber-optic communication]]s, where they permit transmission over longer distances and at higher [[Bandwidth (computing)|bandwidths]] (data transfer rates) than electrical cables. Fibers are used instead of [[metal]] wires because signals travel along them with less [[Attenuation|loss]]; in addition, fibers are immune to [[electromagnetic interference]], a problem from which metal wires suffer.<ref>{{cite book|ref=Senior|last1=Senior|first1=John M.|last2=Jamro|first2=M. Yousif|title=Optical fiber communications: principles and practice|date=2009|publisher=Pearson Education|isbn=978-0130326812|pages=7–9}}</ref> Fibers are also used for [[Illumination (lighting)|illumination]] and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a [[fiberscope]].<ref>{{cite web|title=Birth of Fiberscopes|url=http://www.olympus-global.com/en/corc/history/story/endo/fiber/|website=www.olympus-global.com |publisher=Olympus Corporation|access-date=17 April 2015}}</ref> Specially designed fibers are also used for a variety of other applications, some of them being [[fiber optic sensor]]s and [[fiber laser]]s.<ref>{{cite journal|last1=Lee|first1=Byoungho|title=Review of the present status of optical fiber sensors.|journal=Optical Fiber Technology|date=2003|volume=9|issue=2|pages=57–79 |doi=10.1016/s1068-5200(02)00527-8|bibcode=2003OptFT...9...57L}}</ref>

Optical fibers typically include a [[Core (optical fiber)|core]] surrounded by a transparent [[Cladding (fiber optics)|cladding]] material with a lower [[index of refraction]]. Light is kept in the core by the phenomenon of [[total internal reflection]] which causes the fiber to act as a [[Waveguide (optics)|waveguide]].<ref>[[#Senior|Senior]], pp. 12–14</ref> Fibers that support many propagation paths or [[transverse mode]]s are called [[multi-mode fiber]]s, while those that support a single mode are called [[single-mode fiber]]s (SMF).<ref name="pears1">{{cite book|last1=Pearsall|first1=Thomas|title=Photonics Essentials, 2nd edition|publisher=McGraw-Hill|date=2010|url=https://www.mheducation.com/highered/product/photonics-essentials-second-edition-pearsall/9780071629355.html|isbn=978-0-07-162935-5}}</ref> Multi-mode fibers generally have a wider core diameter<ref>{{Cite book|url=https://books.google.com/books?id=HFMiAQAAMAAJ&q=Multi-mode+fibers+generally+have+a+wider+core+diameter+and+are+used+for+short-distance+communication+links|title=The Optical Industry & Systems Purchasing Directory|date=1984|publisher=Optical Publishing Company|language=en}}</ref> and are used for short-distance communication links and for applications where high power must be transmitted.<ref>{{Cite book|url=https://books.google.com/books?id=Nrs6DwAAQBAJ&q=multimode+fiber+used+for+short+communication+or+high+power+transfer&pg=RA1-PA19|title=Photonic Devices and Systems|last=Hunsperger|date=2017-10-19|publisher=Routledge|isbn=9781351424844|language=en}}</ref> Single-mode fibers are used for most communication links longer than {{convert|1000|sp=us|m|ft}}.

Being able to join optical fibers with low loss is important in fiber optic communication.<ref>[[#Senior|Senior]], p. 218</ref> This is more complex than joining electrical wire or cable and involves careful [[Cleave (fiber)|cleaving]] of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a [[Fusion splicing|fusion splice]] is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a [[mechanical splice]], where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized [[optical fiber connector]]s.<ref>[[#Senior|Senior]], pp. 234–235</ref>

The field of applied science and engineering concerned with the design and application of optical fibers is known as ''fiber optics''. The term was coined by Indian-American physicist [[Narinder Singh Kapany]], who is widely acknowledged as the father of fiber optics.<ref name="southasia.ucsc.edu">{{cite web|url=http://southasia.ucsc.edu/endowed-chairs/narinder-singh-kapany.html|title=Narinder Singh Kapany Chair in Opto-electronics|publisher=ucsc.edu}}</ref>

== Историја ==
[[File:DanielColladon's Lightfountain or Lightpipe,LaNature(magazine),1884.JPG|thumb|left|[[Jean-Daniel Colladon|Даниел Коладон]] је први пут описао ову „светлосну фонтану“ или „светлосну цев“ у чланку из 1842. године под насловом „О рефлексијама зрака светлости унутар параболичне течности“. Ова конкретна илустрација потиче из каснијег Коладоновог чланка из 1884. године.]]

Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by [[Jean-Daniel Colladon|Daniel Colladon]] and [[Jacques Babinet]] in [[Paris]] in the early 1840s. [[John Tyndall]] included a demonstration of it in his public lectures in [[London]], 12 years later.<ref name=regis>{{cite book
|last =Bates
|first =Regis J
|title =Optical Switching and Networking Handbook
|publisher =McGraw-Hill
|year= 2001
|location =New York
|isbn=978-0-07-137356-2
|page =10}}</ref> Tyndall also wrote about the property of [[total internal reflection]] in an introductory book about the nature of light in 1870:<ref>{{cite book
|first=John |last=Tyndall
|year=1870 |title=Notes about Light
|chapter=Total Reflexion
|chapter-url=https://archive.org/details/notesofcourseofn00tyndrich}}</ref><ref>{{cite book
|first=John |last=Tyndall
|year=1873
|title=Six Lectures on Light
|url=https://archive.org/details/sixlecturesonlig00tynduoft|publisher=New York : D. Appleton
}}</ref>{{quote|When the light passes from air into water, the refracted ray is bent ''towards'' the [[perpendicular]]... When the ray passes from water to air it is bent ''from'' the perpendicular... If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be ''totally reflected'' at the surface... The angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint glass it is 38°41′, while for a diamond it is 23°42′.}}

In the late 19th and early 20th centuries, light was guided through bent glass rods to illuminate body cavities.<ref>{{cite web |url=http://inventors.about.com/library/weekly/aa980407.htm |title=How Fiber Optics Was Invented |author=Mary Bellis |access-date=2020-01-20}}</ref> Practical applications such as close internal illumination during dentistry appeared early in the twentieth century. Image transmission through tubes was demonstrated independently by the radio experimenter [[Clarence Hansell]] and the television pioneer [[John Logie Baird]] in the 1920s. In the 1930s, [[Heinrich Lamm]] showed that one could transmit images through a bundle of unclad optical fibers and used it for internal medical examinations, but his work was largely forgotten.<ref name=regis/><ref name=Hecht2004/>

In 1953, Dutch scientist {{ill|Bram van Heel|nl}} first demonstrated image transmission through bundles of optical fibers with a transparent cladding.<ref name=Hecht2004>{{cite book |first=Jeff |last=Hecht |title=City of Light: The Story of Fiber Optics |publisher=Oxford University |edition=revised |date=2004 |isbn=9780195162554 |pages=55–70}}</ref> That same year, [[Harold Hopkins (physicist)|Harold Hopkins]] and [[Narinder Singh Kapany]] at [[Imperial College]] in London succeeded in making image-transmitting bundles with over 10,000 fibers, and subsequently achieved image transmission through a 75&nbsp;cm long bundle which combined several thousand fibers.<ref name=Hecht2004/><ref>{{cite journal|author1=Hopkins, H. H. |author2=Kapany, N. S. |journal=Nature|doi=10.1038/173039b0 |volume=173|pages= 39–41 |year=1954 |title=A flexible fibrescope, using static scanning|issue=4392|bibcode = 1954Natur.173...39H |s2cid=4275331 }}</ref><ref>[https://web.archive.org/web/20110629061117/http://nobelprize.org/nobel_prizes/physics/laureates/2009/sciback_phy_09.pdf Two Revolutionary Optical Technologies]. Scientific Background on the Nobel Prize in Physics 2009. Nobelprize.org. 6 October 2009</ref> The first practical fiber optic semi-flexible [[gastroscope]] was patented by [[Basil Hirschowitz]], C. Wilbur Peters, and Lawrence E. Curtiss, researchers at the [[University of Michigan]], in 1956. In the process of developing the gastroscope, Curtiss produced the first glass-clad fibers; previous optical fibers had relied on air or impractical oils and waxes as the low-index cladding material.<ref name=Hecht2004/>

Kapany coined the term ''fiber optics'', wrote a 1960 article in ''Scientific American'' that introduced the topic to a wide audience, and wrote the first book about the new field.<ref name=Hecht2004/><ref>[http://news.rediff.com/report/2009/oct/08/how-india-missed-another-nobel-prize.htm How India missed another Nobel Prize – Rediff.com India News]. News.rediff.com (2009-10-12). Retrieved on 2017-02-08.</ref>

The first working fiber-optic data transmission system was demonstrated by German physicist [[Manfred Börner]] at [[Telefunken]] Research Labs in Ulm in 1965, which was followed by the first patent application for this technology in 1966.<ref>{{cite patent | country = DE | number = 1254513 | status = patent | title = Mehrstufiges Übertragungssystem für Pulscodemodulation dargestellte Nachrichten. | gdate = 1967-11-16 | inventor = Börner, Manfred | assign1 = Telefunken Patentverwertungsgesellschaft m.b.H.}}</ref><ref>{{cite patent | country = US | number = 3845293 | status = patent | title = Electro-optical transmission system utilizing lasers| inventor = Börner, Manfred }}</ref> In 1968, NASA used fiber optics in the television cameras that were sent to the moon. At the time, the use in the cameras was [[Classified information in the United States|classified]] ''confidential'', and employees handling the cameras had to be supervised by someone with an appropriate security clearance.<ref>[https://history.nasa.gov/alsj/MSC-SESD-28-105.pdf Lunar Television Camera. Pre-installation Acceptance Test Plan]. NASA. 12 March 1968</ref>

[[Charles K. Kao]] and [[George A. Hockham]] of the British company [[Standard Telephones and Cables]] (STC) were the first, in 1965, to promote the idea that the [[attenuation]] in optical fibers could be reduced below 20 [[decibel]]s per kilometer (dB/km), making fibers a practical communication medium.<ref name=hecht1999>{{cite book
|last= Hecht
|first= Jeff
|title= City of Light, The Story of Fiber Optics
|publisher= [[Oxford University Press]]
|location= New York
|year= 1999
|url=https://books.google.com/books?id=4oMu7RbGpqUC&pg=PA114
|isbn= 978-0-19-510818-7
|page=114}}</ref> They proposed that the attenuation in fibers available at the time was caused by impurities that could be removed, rather than by fundamental physical effects such as scattering. They correctly and systematically theorized the light-loss properties for optical fiber and pointed out the right material to use for such fibers—[[silica glass]] with high purity. This discovery earned Kao the [[Nobel Prize in Physics]] in 2009.<ref>{{cite web |url=http://nobelprize.org/nobel_prizes/physics/laureates/2009/press.html|title=Press Release&nbsp;— Nobel Prize in Physics 2009|publisher=The Nobel Foundation|access-date=2009-10-07}}</ref> The crucial attenuation limit of 20&nbsp;dB/km was first achieved in 1970 by researchers [[Robert D. Maurer]], [[Donald Keck]], [[Peter C. Schultz]], and Frank Zimar working for American glass maker [[Corning Glass Works]].<ref name=hecht1999b>{{cite book
|last= Hecht
|first= Jeff
|title= City of Light, The Story of Fiber Optics
|publisher= [[Oxford University Press]]
|location= New York
|year= 1999
|url=https://books.google.com/books?id=4oMu7RbGpqUC&pg=PA114
|isbn= 978-0-19-510818-7
|page=271}}</ref> They demonstrated a fiber with 17&nbsp;dB/km attenuation by [[doping (semiconductor)|doping]] silica glass with [[titanium]]. A few years later they produced a fiber with only 4&nbsp;dB/km attenuation using [[germanium dioxide]] as the core dopant. In 1981, [[General Electric]] produced fused [[quartz]] [[ingots]] that could be drawn into strands {{convert|25|mi|km}} long.<ref>{{cite web |url=http://www.ge.com/innovation/timeline/eras/continuing_tradition.html |title=1971–1985 Continuing the Tradition |work=GE Innovation Timeline |publisher=General Electric Company |access-date=2012-09-28}}</ref>

Initially, high-quality optical fibers could only be manufactured at 2 meters per second. Chemical engineer [[Thomas Mensah (engineer)|Thomas Mensah]] joined Corning in 1983 and increased the speed of manufacture to over 50 meters per second, making optical fiber cables cheaper than traditional copper ones.<ref name=RSCiB>{{cite web |title=About the Author – Thomas Mensah |url=http://rightstuffcomesinblack.com/about-the-author-dr-thomas-mensah |publisher=The Right Stuff Comes in Black |access-date=29 March 2015}}</ref> These innovations ushered in the era of optical fiber telecommunication.

The Italian research center [[CSELT]] worked with Corning to develop practical optical fiber cables, resulting in the first metropolitan fiber optic cable being deployed in Turin in 1977.<ref>{{cite journal |vauthors=Catania B, Michetti L, Tosco F, Occhini E, Silvestri L |title=First Italian Experiment with a Buried Optical Cable |url=http://www.chezbasilio.org/immagini/cos1_tests.pdf |journal=Proceedings of 2nd European Conference on Optical Communication (II ECOC) |date=1976 |access-date=2019-05-03}}</ref><ref>[http://archiviostorico.telecomitalia.com/italia-al-telefono-oltre/15-settembre-1977-torino-prima-stesura-al-mondo-di-fibra-ottica-in-esercizi Archivio storico Telecom Italia: 15 settembre 1977, Torino, prima stesura al mondo di una fibra ottica in esercizio.]</ref> CSELT also developed an early technique for splicing optical fibers, called Springroove.<ref>[http://archiviostorico.telecomitalia.com/italia-al-telefono-oltre/springroove-giunto-per-fibre-ottiche-brevettato-nel-1977 Springroove, il giunto per fibre ottiche brevettato nel 1977]. archiviostorico.telecomitalia.com. Retrieved on 2017-02-08.</ref>


== Види још ==
== Види још ==
Ред 11: Ред 76:
* [[Photonic-crystal fiber]]
* [[Photonic-crystal fiber]]
* [[Солитон]]
* [[Солитон]]

== Напомене ==
{{Notelist}}


== Референце ==
== Референце ==
{{reflist}}
{{reflist}}

== Литература ==
{{Refbegin|30em}}
* {{cite book|first=Govind|last=Agrawal|title=Fiber-Optic Communication Systems|publisher=Wiley|year=2010|isbn=978-0-470-50511-3|doi=10.1002/9780470918524|edition=4}}
* {{cite journal | last1 = Gambling | first1 = W. A. | year = 2000 | title = The Rise and Rise of Optical Fibers | journal = IEEE Journal on Selected Topics in Quantum Electronics | volume = 6 | issue = 6| pages = 1084–1093 | doi = 10.1109/2944.902157 | bibcode = 2000IJSTQ...6.1084G | s2cid = 23158230 }}
* Mirabito, Michael M. A.; and Morgenstern, Barbara L., ''The New Communications Technologies: Applications, Policy, and Impact'', 5th Edition. Focal Press, 2004. ({{ISBN|0-240-80586-0}}).
* Mitschke F., ''Fiber Optics: Physics and Technology'', Springer, 2009 ({{ISBN|978-3-642-03702-3}})
* {{cite journal | last1 = Nagel | first1 = S. R. | last2 = MacChesney | first2 = J. B. | last3 = Walker | first3 = K. L. | year = 1982| title = An Overview of the Modified Chemical Vapor Deposition (MCVD) Process and Performance | journal = IEEE Journal of Quantum Electronics | volume = 30| issue = 4| pages = 305–322| doi = 10.1109/TMTT.1982.1131071 | bibcode = 1982ITMTT..30..305N | s2cid = 33979233 }}
* {{cite book|author1=Rajiv Ramaswami|author2=Kumar Sivarajan|author3=Galen Sasaki|title=Optical Networks: A Practical Perspective|url={{google books|plainurl=yes|id=WpByp4Ip0z8C}}|date=27 November 2009|publisher=Morgan Kaufmann|isbn=978-0-08-092072-6}}
* [https://www.thefoa.org/Lennie/ ''Lennie Lightwave's Guide to Fiber Optics''], The Fiber Optic Association, 2016.
* {{cite book |first=Thomas L. |last=Friedman |title=The World is Flat |publisher=Picador |year=2007 |isbn=978-0-312-42507-4 |url-access=registration |url=https://archive.org/details/worldisflat00thom }} The book discusses how fiber optics has contributed to [[globalization]], and has revolutionized communications, business, and even the distribution of capital among countries.
* [https://telecom-info.njdepot.ericsson.net/site-cgi/ido/docs.cgi?ID=SEARCH&DOCUMENT=GR-771& GR-771, ''Generic Requirements for Fiber Optic Splice Closures''], Telcordia Technologies, Issue 2, July 2008. Discusses fiber optic splice closures and the associated hardware intended to restore the mechanical and environmental integrity of one or more fiber cables entering the enclosure.
* {{cite web|last=Paschotta|first=Rüdiger| title=Tutorial on Passive Fiber optics| url=https://www.rp-photonics.com/passive_fiber_optics.html| publisher=RP Photonics| access-date=17 October 2013}}

{{Refend}}


== Спољашње везе ==
== Спољашње везе ==
{{Commonscat|Optical fibers}}
{{Commons category|Optical fibers}}
* [http://www.thefoa.org/ -{The Fiber Optic Association}-] {{en}}
* [http://www.thefoa.org/ -{The Fiber Optic Association}-] {{en}}
* [http://www.rp-photonics.com/fibers.html Оптичко влакно], чланак у ''-{Encyclopedia of Laser Physics and Technology}-'' {{en}}
* [http://www.rp-photonics.com/fibers.html Оптичко влакно], чланак у ''-{Encyclopedia of Laser Physics and Technology}-'' {{en}}
* [https://web.archive.org/web/20160307202713/http://fabila.com/proyectos/ftth/tecnologia.asp Како се праве оптичка влакна], видео. {{en}}
* [https://web.archive.org/web/20160307202713/http://fabila.com/proyectos/ftth/tecnologia.asp Како се праве оптичка влакна], видео. {{en}}
* [http://ocw.mit.edu/resources/res-6-005-understanding-lasers-and-fiberoptics-spring-2008/laser-fundamentals-i/ -{MIT Video Lecture: Understanding Lasers and Fiberoptics}-] {{en}}
* [http://ocw.mit.edu/resources/res-6-005-understanding-lasers-and-fiberoptics-spring-2008/laser-fundamentals-i/ -{MIT Video Lecture: Understanding Lasers and Fiberoptics}-] {{en}}
* "[http://www.gare.co.uk/technology_watch/fibre.htm Fibre optic technologies]", Mercury Communications Ltd, August 1992.
* "[http://www.gare.co.uk/technology_watch/photo.htm Photonics & the future of fibre]", Mercury Communications Ltd, March 1993.
* "[https://web.archive.org/web/20181023040952/https://arcelect.com/fibercable.htm Fiber Optic Tutorial]" Educational site from Arc Electronics
* [http://spie.org/Documents/Publications/00%20STEP%20Module%2007.pdf Fundamentals of Photonics: Module on Optical Waveguides and Fibers]
* [http://webdemo.inue.uni-stuttgart.de/webdemos/02_lectures/uebertragungstechnik_2/chromatic_dispersion Webdemo for chromatic dispersion] at the Institute of Telecommunicatons, University of Stuttgart

{{Authority control}}


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Верзија на датум 1. мај 2021. у 21:43

Шаблон:Short description

Више оптичких влакана које чине језгро оптичког кабла
Инсталерска екипа ради на постављању оптичког кабла са 432 влакна испод улица Менхетна, Њујорк Сити
TOSLINK фибер оптички аудио кабл чији један крај је обасјан црвеним светлом преноси светло на други крај
Зидни ормар који садржи међусобне везе оптичких влакана. Жути каблови су једносмерна влакна; наранџасти и аква каблови су вишемодна влакна: 50/125 µm OM2 и 50/125 µm OM3 влакна.

Оптичко влакно је врста оптичког таласовода радијалне симетрије, која „вођење“ електромагнетског таласа заснива на ефекту тоталне унутрашње рефлексије. flexible, Транспарентно влакно микрометарских димензија, израђено од стакла или пластике, служи као медијум у оптичком каблу за пренос информација помоћу светлости.[1] Влакна имају концентричну слојевиту структуру. У средини се налази језгро, које води светлост, окружено са омотачем (јакном) са нешто нижим индексом преламања и заштитним слојем пластике. У зависности од примене, пречник језгра је у распону од неколико до више стотина микрона. А од дијаметра и профила индекса преламања између језгра и омотача, зависи број режима (модова) способних да пропагирају кроз влакно. Оптичка влакана могу бити мономодна (једнорежимска) и мултимодна (вишережимска). Кроз једнорежимска се простире само један мод ласерске светлости и оваква влакна се користе за пренос информација на веће удаљености, док се кроз вишережимска влакна простире више модова и ова влакна се користе за приступне мреже. Овакав пренос информација је бржи, поузданији и сигурнији од преноса бакарним кабловима.

Optical fibers are used most often as a means to transmit light[а] between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer.[2] Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope.[3] Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers.[4]

Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide.[5] Fibers that support many propagation paths or transverse modes are called multi-mode fibers, while those that support a single mode are called single-mode fibers (SMF).[6] Multi-mode fibers generally have a wider core diameter[7] and are used for short-distance communication links and for applications where high power must be transmitted.[8] Single-mode fibers are used for most communication links longer than 1.000 m (3.300 ft).

Being able to join optical fibers with low loss is important in fiber optic communication.[9] This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a fusion splice is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a mechanical splice, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors.[10]

The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Indian-American physicist Narinder Singh Kapany, who is widely acknowledged as the father of fiber optics.[11]

Историја

Даниел Коладон је први пут описао ову „светлосну фонтану“ или „светлосну цев“ у чланку из 1842. године под насловом „О рефлексијама зрака светлости унутар параболичне течности“. Ова конкретна илустрација потиче из каснијег Коладоновог чланка из 1884. године.

Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon and Jacques Babinet in Paris in the early 1840s. John Tyndall included a demonstration of it in his public lectures in London, 12 years later.[12] Tyndall also wrote about the property of total internal reflection in an introductory book about the nature of light in 1870:[13][14]

When the light passes from air into water, the refracted ray is bent towards the perpendicular... When the ray passes from water to air it is bent from the perpendicular... If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface... The angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint glass it is 38°41′, while for a diamond it is 23°42′.

In the late 19th and early 20th centuries, light was guided through bent glass rods to illuminate body cavities.[15] Practical applications such as close internal illumination during dentistry appeared early in the twentieth century. Image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. In the 1930s, Heinrich Lamm showed that one could transmit images through a bundle of unclad optical fibers and used it for internal medical examinations, but his work was largely forgotten.[12][16]

In 1953, Dutch scientist nl [Bram van Heel] first demonstrated image transmission through bundles of optical fibers with a transparent cladding.[16] That same year, Harold Hopkins and Narinder Singh Kapany at Imperial College in London succeeded in making image-transmitting bundles with over 10,000 fibers, and subsequently achieved image transmission through a 75 cm long bundle which combined several thousand fibers.[16][17][18] The first practical fiber optic semi-flexible gastroscope was patented by Basil Hirschowitz, C. Wilbur Peters, and Lawrence E. Curtiss, researchers at the University of Michigan, in 1956. In the process of developing the gastroscope, Curtiss produced the first glass-clad fibers; previous optical fibers had relied on air or impractical oils and waxes as the low-index cladding material.[16]

Kapany coined the term fiber optics, wrote a 1960 article in Scientific American that introduced the topic to a wide audience, and wrote the first book about the new field.[16][19]

The first working fiber-optic data transmission system was demonstrated by German physicist Manfred Börner at Telefunken Research Labs in Ulm in 1965, which was followed by the first patent application for this technology in 1966.[20][21] In 1968, NASA used fiber optics in the television cameras that were sent to the moon. At the time, the use in the cameras was classified confidential, and employees handling the cameras had to be supervised by someone with an appropriate security clearance.[22]

Charles K. Kao and George A. Hockham of the British company Standard Telephones and Cables (STC) were the first, in 1965, to promote the idea that the attenuation in optical fibers could be reduced below 20 decibels per kilometer (dB/km), making fibers a practical communication medium.[23] They proposed that the attenuation in fibers available at the time was caused by impurities that could be removed, rather than by fundamental physical effects such as scattering. They correctly and systematically theorized the light-loss properties for optical fiber and pointed out the right material to use for such fibers—silica glass with high purity. This discovery earned Kao the Nobel Prize in Physics in 2009.[24] The crucial attenuation limit of 20 dB/km was first achieved in 1970 by researchers Robert D. Maurer, Donald Keck, Peter C. Schultz, and Frank Zimar working for American glass maker Corning Glass Works.[25] They demonstrated a fiber with 17 dB/km attenuation by doping silica glass with titanium. A few years later they produced a fiber with only 4 dB/km attenuation using germanium dioxide as the core dopant. In 1981, General Electric produced fused quartz ingots that could be drawn into strands 25 mi (40 km) long.[26]

Initially, high-quality optical fibers could only be manufactured at 2 meters per second. Chemical engineer Thomas Mensah joined Corning in 1983 and increased the speed of manufacture to over 50 meters per second, making optical fiber cables cheaper than traditional copper ones.[27] These innovations ushered in the era of optical fiber telecommunication.

The Italian research center CSELT worked with Corning to develop practical optical fiber cables, resulting in the first metropolitan fiber optic cable being deployed in Turin in 1977.[28][29] CSELT also developed an early technique for splicing optical fibers, called Springroove.[30]

Види још

Напомене

  1. ^ Infrared light is used in optical-fiber communication due to its lower attenuation

Референце

  1. ^ „Optical Fiber”. www.thefoa.org. The Fiber Optic Association. Приступљено 17. 4. 2015. 
  2. ^ Senior, John M.; Jamro, M. Yousif (2009). Optical fiber communications: principles and practice. Pearson Education. стр. 7—9. ISBN 978-0130326812. 
  3. ^ „Birth of Fiberscopes”. www.olympus-global.com. Olympus Corporation. Приступљено 17. 4. 2015. 
  4. ^ Lee, Byoungho (2003). „Review of the present status of optical fiber sensors.”. Optical Fiber Technology. 9 (2): 57—79. Bibcode:2003OptFT...9...57L. doi:10.1016/s1068-5200(02)00527-8. 
  5. ^ Senior, pp. 12–14
  6. ^ Pearsall, Thomas (2010). Photonics Essentials, 2nd edition. McGraw-Hill. ISBN 978-0-07-162935-5. 
  7. ^ The Optical Industry & Systems Purchasing Directory (на језику: енглески). Optical Publishing Company. 1984. 
  8. ^ Hunsperger (2017-10-19). Photonic Devices and Systems (на језику: енглески). Routledge. ISBN 9781351424844. 
  9. ^ Senior, p. 218
  10. ^ Senior, pp. 234–235
  11. ^ „Narinder Singh Kapany Chair in Opto-electronics”. ucsc.edu. 
  12. ^ а б Bates, Regis J (2001). Optical Switching and Networking Handbook. New York: McGraw-Hill. стр. 10. ISBN 978-0-07-137356-2. 
  13. ^ Tyndall, John (1870). „Total Reflexion”. Notes about Light. 
  14. ^ Tyndall, John (1873). Six Lectures on Light. New York : D. Appleton. 
  15. ^ Mary Bellis. „How Fiber Optics Was Invented”. Приступљено 2020-01-20. 
  16. ^ а б в г д Hecht, Jeff (2004). City of Light: The Story of Fiber Optics (revised изд.). Oxford University. стр. 55—70. ISBN 9780195162554. 
  17. ^ Hopkins, H. H.; Kapany, N. S. (1954). „A flexible fibrescope, using static scanning”. Nature. 173 (4392): 39—41. Bibcode:1954Natur.173...39H. S2CID 4275331. doi:10.1038/173039b0. 
  18. ^ Two Revolutionary Optical Technologies. Scientific Background on the Nobel Prize in Physics 2009. Nobelprize.org. 6 October 2009
  19. ^ How India missed another Nobel Prize – Rediff.com India News. News.rediff.com (2009-10-12). Retrieved on 2017-02-08.
  20. ^ DE patent 1254513, Börner, Manfred, "Mehrstufiges Übertragungssystem für Pulscodemodulation dargestellte Nachrichten.", issued 1967-11-16, assigned to Telefunken Patentverwertungsgesellschaft m.b.H. 
  21. ^ US patent 3845293, Börner, Manfred, "Electro-optical transmission system utilizing lasers" 
  22. ^ Lunar Television Camera. Pre-installation Acceptance Test Plan. NASA. 12 March 1968
  23. ^ Hecht, Jeff (1999). City of Light, The Story of Fiber Optics. New York: Oxford University Press. стр. 114. ISBN 978-0-19-510818-7. 
  24. ^ „Press Release — Nobel Prize in Physics 2009”. The Nobel Foundation. Приступљено 2009-10-07. 
  25. ^ Hecht, Jeff (1999). City of Light, The Story of Fiber Optics. New York: Oxford University Press. стр. 271. ISBN 978-0-19-510818-7. 
  26. ^ „1971–1985 Continuing the Tradition”. GE Innovation Timeline. General Electric Company. Приступљено 2012-09-28. 
  27. ^ „About the Author – Thomas Mensah”. The Right Stuff Comes in Black. Приступљено 29. 3. 2015. 
  28. ^ Catania B, Michetti L, Tosco F, Occhini E, Silvestri L (1976). „First Italian Experiment with a Buried Optical Cable” (PDF). Proceedings of 2nd European Conference on Optical Communication (II ECOC). Приступљено 2019-05-03. 
  29. ^ Archivio storico Telecom Italia: 15 settembre 1977, Torino, prima stesura al mondo di una fibra ottica in esercizio.
  30. ^ Springroove, il giunto per fibre ottiche brevettato nel 1977. archiviostorico.telecomitalia.com. Retrieved on 2017-02-08.

Литература

Спољашње везе

Оптичко влакно на Викимедијиној остави.
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