What is Optical fiber: Definition and 38 Discussions

An optical fiber (or fibre in British English) is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light 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. 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. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers.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. 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). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,000 meters (3,300 ft).Being able to join optical fibers with low loss is important in fiber optic communication. 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.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.

View More On Wikipedia.org
  1. F

    Evaluate the outgoing radiation from an optical fiber on a surface

    The geometric configuration that I am adopting is the following, I hope you understand. The optical fiber is positioned relative to the bottom surface at a height ##a## and an angle ##\alpha## with respect to the y-axis in the yz-plane with x = 0. ##b## is the distance between the origin and...
  2. M

    I Light coupling from optical fiber to glass?

    Hey everyone, I am trying to couple light from an optical fiber connected to an LED (365nm) into a small glass capillary which is pulled on one end and should be used as a small light source. The idea is to use the glass as a light guide. Has anyone tips for efficient incoupling of the light? I...
  3. X

    B Multimode optical fiber, physics beginner help :D

    Hello ! I have a problem understanding how light works in multimode optical fiber. What do I mean in single-mode optical fiber there is single light which contains information. In multimode there can be multiple lights with multiple information. Like here 1st picture contains multiple...
  4. S

    Elliptical facet cylindrical optical fiber - Mathieu equation

    Let's say I have three modes in a fiber that is elliptical cylinder shaped (cylinder with elliptical facet), as in the image below (the source:Optical Engineering, 46(4), 045003 (2007)) so what is the equations that describe these fields..
  5. E

    Modeling/Analysis of optical fibers

    Hello PF, I need some guide points to help me formulate a project idea on the topic of optical fibers. Namely, the professor suggested I should look for topics on modeling of optical fibers, analysis of different optical fibers, characteristics etc. and to work in a simulator, or perform a...
  6. S

    Modes of Optical Fiber propagation

    What actually is a mode of optical fiber propagation?Is it similar to modes which correspond to various configurations as in standing waves on a string ? Also How correct is it to consider no. of rays as no of modes?
  7. KT KIM

    How can light propagate through Hollow optical fiber.

    Now I am studying a bit of optical fibers. And of course generally optical fiber works because of total reflection property of the light, which happens when the light from higher medium hits the lower medium material. However I recently found out that there also is a thing 'Hollow optical...
  8. I

    How to calculate attenuation for optical fiber bundle?

    Hi, If I understood it correctly, the coefficient of attenuation for a single optical fiber, is alpha = (10/L)*log(P(0)/P(L)). Assuming if I knew the properties of the optical fiber and the amount of optical fiber in the bundle, then the total attenuation for the bundle is approximately number...
  9. A

    Directing sunlight into the optical fiber

    Hello Is it possible to direct sunlight into the optical fiber by magnifying glass and a prism like the image below? if yes , what shape of prism should i use to do this? Thank you
  10. S

    Number of modes in optical fiber

    Homework Statement Can a single mode fiber become multimode if the wavelength of the light passed through it is small enough? I put a HeNe laser (633nm) through what I thought was a single mode fiber. If it's supposed to operate at 1300nm, then would a low wavelength of 633nm cause multiple...
  11. N

    Is it possible to collimate monochromatic light with a taper?

    I am ignorant about laser physics, but i have this idea of collimating monochromatic light with an optical fiber/cable that is cone shaped: at inlet the cone has a wide diameter (several hundred microns - like an ordinary optical fiber, which might be used as a light source), on the other end it...
  12. G

    Where is the information in an optical fiber?

    Hi. I know how optical fibers work but where is the information in the light signal passing through it? Which characteristics of the electric field carry it? I begun to think about it because I was intrigued if they took into account things like the Goos-Hänchen shift or angular deviations in...
  13. W

    Estimating loss-limited transmission distance

    Homework Statement A high-speed optical data communication system is composed of a transmitter, an unamplified transmission fiber link, and a receiver. The optical transmitter generates a 10-Gb/s non-return-to-zero (NRZ) signal using a 1550-nm laser diode (linewidth=2 MHz) followed by a...
  14. Daoyang

    What creative possibilities lie at the intersection of science and art?

    Hi all! So here I am, a Frenchman living in China, working on some madcap art projects involving science. I already posted a question here about one art installation I am working on, which involves stars, light, and (possibly?) optical fibers... Feel free to check it out if you're interested...
  15. Daoyang

    Can I control the lighting of thousands of optical fibers?

    Hi everyone! This is my first post. I hope I am posting in the right place -- if not, please let me know. I am also hoping my question will not sound too absurd; I am no physicist, just someone who would like to use complex technology to create an art installation, and I'm having a hard time...
  16. C4l1

    How Can the Euler-Lagrange Equations Describe Light Path in Optical Fibers?

    Homework Statement An optical fiber is one way to guide light efficiently from one point to an other. It is currently used for data communication: it offers low loss and very high bandwidth, ideal for the requirements of the internet. Generally, we can describe an optical fiber as a medium with...
  17. S

    Refraction through an optical fiber

    Homework Statement Given a "new type" of optical fiber (index of refraction n = 1.23), a laser beam is incident on the flat end of a straight fiber in air. Assume nair = 1.00. What is the maximum angle of incidence Ø1 if the beam is not to escape from the fiber? (See attached file for...
  18. Y

    Return loss of transmission line and optical fiber

    In wikipedia, it said for optical fiber, a loss that takes place at discontinuities of refractive index, especially at an air-glass interface such as a fiber endface. At those interfaces, a fraction of the optical signal is reflected back toward the source. But what I learned in tranmission...
  19. tipu_sultan

    What is the meaning in the 144 Optical Fiber Cable? Especially why 144

    During studying the telecom underground cable network I came across the Optical Fiber Cable having the 144 fibers (single mode). I want to know why 144? Is this a Some standard to have 144 fibers in one cable? I have also viewed some of the datasheet having 144 fibers Optical Fiber Cable...
  20. E

    Stimulated Brillouin scattering inside an optical fiber

    Hello everyone I need some one once and for all to give me the steps to have a clear step by step idea about the stimulated Brillouin scattering inside an optical fiber please and thank you
  21. S

    Transmitting visible light via optical fiber

    Hi, A colleague of mine at work has this idea of using a focusing lens to focus the visible light into a optical fiber and guide it to some destination, e.g. room with no windows. I have no experience in optics, or in QED (only some "layman" knowledge of monochromatic light and its...
  22. H

    Total internal refraction inside an optical fiber

    Homework Statement In the attachment below, a ray of light undergoes total internal reflection in an optical fiber such that the angle θ between the ray and the interface is 47°. Assuming the fiber is surrounded by air, what is the minimum index of refraction necessary for this to occur...
  23. K

    Optics - reduce image and launch into optical fiber

    Dear all, I'd like to know if there is a way of reducing an image and launching it into the core of an optical fiber. By other words, I'm not interested in the spatial distribution of the light (the image itself) but I'm interested in gathering all the light coming from the scene and...
  24. T

    Constant in Modes of Optical Fiber

    Dear All, Many thanks for reading this query. Actually, I am having problem in measuring the mode fields of Optical fiber at the core-cladding interface analytically for modes LP01 and LP11. The modes are normally given by eq 2.165 (image attached). To my knowledge these constants A and C...
  25. D

    Medical Have you ever had an optical fiber shoved up

    ... your nose and down your throat? I had a throat ache that wouldn't go away, and so to see what was going on, they did this medical procedure. The interesting part is that I never saw it coming. They asked questions, cleaned away ear wax, sprayed a liquid in my nostrils, and out of no...
  26. P

    Light in an optical fiber - variational calculus

    Homework Statement Homework Equations \frac{\delta{F}}{\delta{y}} - \frac{d}{dx}\frac{\delta{F}}{\delta{y'}} = 0The Attempt at a Solution I'm having trouble setting this one up. If I let the functional be F(x,x',y) = n(y)\sqrt{1+(x')^2} Applying the LE equation I obtain...
  27. Y

    Maximum length of an optical fiber

    Hi all, I have a question regarding a fiber optics based communications system: The light source is a Fabry-Perot LASER, which outputs 5 longitudinal modes. The communication rates are: \Delta\omega=100Grads^{-1}, B=10Gbs^{-1}, and the dispersion coefficient is \beta_{2}=10\frac{ps^{2}}{Km}...
  28. C

    Interference Patterns in Optical Fibers: Causes and Solutions

    Hey all I am using optical fibers as a read-out medium form a PCB. I see interference in the data through this fiber. Can someone shed a light on the interference patterns on the optical fiber? Usually one should not see any electronic noise in fibers. How true is it and how to get around it...
  29. G

    Help needed: coupling light from a LED into an optical fiber

    First let me preface this by saying by physics-fu is remedial at best. I am a neuroscientist by training, but need a little help with piece of equipment I am designing, so any ideas or input would be greatly appreciated. Basically, I need to figure out a way to efficiently couple a light...
  30. R

    Index of refraction of an optical fiber

    Homework Statement The glass core of an optical fiber has an index of refraction 1.62. The index of refraction of the cladding is 1.47. What is the maximum angle a light ray can make with the wall of the core if it is to remain inside the fiber? Homework Equations theta = sin ^-1...
  31. O

    Optical Fiber Transfer Function (attenuation and dispersion)

    I have a few questions regarding the transfer function of a SMF. I'm using the below equation to simulate the effect a single mode fiber (SMF) has on the optical field after some distance \textit{z}. \begin{equation} S_{out}(\omega) = S_{in}(\omega)\exp\left...
  32. Q

    How Do You Calculate Parameters for a Multimode Step Index Fiber?

    Homework Statement A multimode step index fiber has a relative index difference of 1% and a core refractive index of 1.5. The number of modes propagating at a wavelength of 1.3μm is 1100. Estimate the diameter of the fiber core. An optical link of 6 km uses the above fiber. Find (a) the...
  33. N

    Can a CO2 laser be cabled with optical fiber?

    Hi, i have a question about optical fiber and CO2 laser Can a CO2 laser be cabled with optical fiber? Wavelength of 10 micron
  34. S

    Multipath dispersion of a pulse of light in an optical fiber.

    Homework Statement Multipath dispersion of a pulse of light in an optical fiber. How is this problem solved?
  35. J

    Material dispersion calculation (optical fiber)

    Material dispersion in optical fiber is defined as D = (-λ/c)×(d²n/dλ²) λ is wavelength, c is speed of light and n is refractive index. I was given a graph of λ²×(d²n/dλ²) against λ, refractive index of core of fiber, index difference and diameter of the core and cladding. What I would like to...
  36. T

    Optical Fiber attenuation coefficient

    Hi, I am curious to know what is a typical numerical value for the attenuation coefficient of common optical fibre. Please don't include anything strange in the units like dB since I am new to that. Thanks.
  37. E

    Optical fiber transmitter and receiver (photodarlington)

    Hello, How can we convert parallel-to-serial address and send it as an optical signal? Have a look at the link below if you folks don't know what I mean - the last (3-4 lines) paragraph of the pdf file: http://www.hep.yorku.ca/menary/courses/electronics/3150/lab_manual/opt.pdf...
  38. Evo

    Biomimetics - optical fiber sponge

    I thought this was interesting. Anyone here into biomimetics that has additional examples they can share? (see link for full article) Bell Labs scientists find novel optical fibers in deep-sea sponges Scientists from Lucent Technologies' Bell Labs have found that a deep-sea sponge contains...