What is Fiber optics: Definition and 48 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.

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  1. hagopbul

    B Is this material is good for fiber optics and who would buy it?

    Hello All : as i try to create better economical situation for my self , as some of you noticed that i tried to enhance few things in engines , although it did not quaitly work out it lead to another invention , i couldnt change it yet to economical benefit , due to tests required , and dont...
  2. benagastov

    I Photodetector Output & Refractive Index of FO Cladding/Coating

    After I finished preparing gas chamber for testing optical fiber as gas sensor, my supervisor asked me to measure the difference of refractive index from several optical fiber with different coatings. I knew there is Evanescent Field and Skin Depth effect, but what kind of mathematical formula...
  3. A

    I Light coupling in fiber optic cables

    Hi Everyone! I have a photonics problem that I was wondering if anyone may be able to shed some light on (no pun intended). I work for a company that is designing a fiber optic emitter/detector as a part of one of our products and we've noticed something that would appear to defy physics...

    I Help Needed for Lens Selection for Fiber optics

    I am using a fiber optic cable through which led light propogate, fiber's half acceptance agle is 30 degree. I want to make the light (diverging)comes out of fiber into collimated beam and this collimated beam will pass through filters, sample and will be used for Fluoroscence application. hope...
  5. iVenky

    I Single-mode vs multi-mode fiber coupling

    Hi, Is coupling light from a laser into a single-mode fiber (transverse electric) more difficult than coupling to a multi-mode fiber? If so, is it due to the geometry? Does the laser light have multiple modes to begin with or it can be designed to have just one mode? Thanks
  6. T

    Photons in Fiber Optics V Solar Sails

    Solar sails use the push of photons on a mirror. Would it work to use the push of photons in the atoms in fiber optic cables so the question is would there be push and how much on 1 mile of a space train 50 feet wide with 1 foot thick of fiber optics. Here's how I think it would be nearly...
  7. G

    A Fiber Optics Bandwidth Question

    Hi everyone :] This is my first time here. I have this Quantum Optics question (though I don't believe there is anything QM about this question, so please let me know if I've incorrectly placed this thread) as part of a (nonmarked) assignment. Here's the question: "What is the maximal...
  8. B

    I All-fiber Mach-Zehnder interferometer

    Experimentalists, would you mind sharing your experience building a fiber-based Mach-Zehnder interferometer? What equipment did you use? How hard is it to achieve the same length of both arms with the fiber and couplers that you can buy online? And how sensitive is the resulting interferometer...
  9. D

    How Is the Minimum Bend Radius of a Fiber Optic Cable Determined?

    If there is a fiber optic cable with a diameter d, the index of refraction of the cladding the cable is given, and so is the index of refraction core of the cable, how would you formulate an equation for the minimum radius of bend the cable can have? Thank you in advance.
  10. M

    How can I determine the length of a Multimode fiber?

    I have a step index SMS (single-multi-single mode fiber) with an equal lateral splicing offset at both junctions. Refractive indexes, offset and radius of cores are given. This device is fed by a broad-band source and the spectral response collected by an Optical Spectrum Analyzer is given...
  11. S

    Max distance of multimode fiber without repeater station

    I have the task to design a system with a multimode fibre optic cable that is 45 km long, but no repeater station. Are optical amplifiers repeater stations? How to get the signal to carry for 45 km? I read that multimode fibres are quite short-range.
  12. C

    I keep runing in circles around this optic fiber question....

    Hi everyone I can not seem to get the right formulas to finish this question. I keep on beating my head against a wall for hours now. It just feels like I can not get the right formula to help me out...Is this some sort of trick question? Note if the image does not load here is the link ->...
  13. Lord Crc

    Observation of laser pulse propagation in optical fibers

    Just wanted to share this, mainly because I really liked the videos (found in the supplementary section at the end). Moderators, feel free to move it to a more appropriate place. Observation of laser pulse propagation in optical fibers with a SPAD camera Recording processes and events that...
  14. A

    Apprentice in fiberoptics and test and measurement equipment

    I come from totally different field. studied previously business management but I was always fascinated by technologies. I find it really difficult to keep up with all the new terms and mathematical equations to follow up. I have to look after each words in every paragraphs. I have searched for...
  15. D

    Max Power Output of 60mW: Troubleshooting Solutions

    I have multiple sources that have a max power output of 60mW, I am using a power meter that can read up to 200mW but when I connect directly to the source channel I get approximately 15mW or less. I have tried a different meter and I have tried different sources only to end up with the same...
  16. Abdul Wali

    Regarding Fiber Optics and Coaxial Cable

    Hi, "limitations/Constraints of Fiber Optics and Coaxial cable for average home user ?"
  17. P

    A Erroneous results when solving fiber mode eigen equation

    Hi, I'm new to this forum and I couldn't find any specific sub-forum for fiber optics/waveguide theory, which my problem is regarding. Please do let me know if I should post this question some where else (and if so, where) on this forum. Anyways, here's my problem: I want to find the effective...
  18. jfulky

    Internal Reflection / Fiber Optics

    Homework Statement 3. A fiber optic cable is essentially a thin fiber of plastic with n = 1.46, surrounded by a protective material with n = 1.32. The light can travel around a bend in the fiber if it can internally reflect inside the fiber. If the diameter of the fiber is d = 0.900 mm find the...
  19. D

    Optical Probe Clarity: Examining Power Loss vs. Beam Spot

    I work in a lab that uses laser probes to test for vibration and other data, currently the lab techs hook up the probe to a laser source and check to see how bright and clear the beam spot is. I have been working on having a signal power budget created for each probe using a laser source and...
  20. D

    100um Core MM Fiber connected to 50um Core 10G SFP Module

    I have two systems that are approx. 300-400ft apart that I am connecting via a 10 Gig fiber connection. The fiber I am using is a 100um core MM fiber and the switches will be using a 50um core OM4 (4700 MHz*km) SFP module. Is there a way to find out what type of loss I should be expecting, is...
  21. F

    SONET protocol for data transmission over fiber optics

    hello forum, I have read about SONET which seems to be a physical layer protocol to transport data over fiber optics. SONET is a TDM (time division multiplexing method). TDM means that that time divided into slots and shared between different users. For example, given three users A, B and C...
  22. E

    Field form in the optic fibers from Maxwell's equations

    Hello! In this document a solution of Maxwell's equations in cylindrical coordinates is provided, in order to determine the electric and magnetic fields inside an optic fiber with a step-index variation. The interface between core and cladding is the cylindrical surface r = a. For example, the...
  23. E

    Cross Phase Modulation in Optical Fibers (Fiber Optics)

    Hello everyone. I have been practicing for my exam in fiber optics, and stumbled upon the following question: We have a transmission system with 3 channels, composed of a single mode fiber and a dispersion compensation fiber. Specifications are given for each. We need to calculate the channel's...
  24. F

    Fiber Optics Qs: Mini-DIO, Fusion, Fanout Cable

    I am working in a project that contain several switchboards that will receive an optical fiber from encoders of the motors that they feed (through an optical transmitter). It appears that to do this we will need Mini-DIOs to connect this fiber cord to optical receivers, which in turn will be...
  25. Padrepapp

    Coupling Xe Arc Lamp into Fiber Bundle

    Hey, we are trying to couple the light of a 75 W Xe Arc Lamp (Hamamatsu L2194) into a 800um(0,8mm) diameter fiber bundle (7 fibers). Now we have 2 plano convex lenses (25mm diameter, 30mm EFL, edmund serial #45-364), the first for collimating the second for focusing onto the fiber. We are...
  26. 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...
  27. F

    How to calculate mode overlap with I(x,y) rather than E(x,y)

    Hi I have a waveguide that is rectangular and multimode that I but-couple to a standard telecom SMF28 fiber. I have imaged the output of the waveguide and the fiber with a 25X microscope objective onto the chip of an IR-camera. Usually the mode overlap is calculated by cross-correlation of the...
  28. R

    What materials are best for creating fiber optics from seaweed or jelly?

    I want to make fiber optics from seaweed or jelly.. It will be happen? Please give me the literature or journal.. Thank you very much for helping me.. :)
  29. A

    Programs Image processing skills in biosensors and fiber optics

    I am currently pursuing a Master's degree in physics with optics as my major and my interests are fiber optics and biosensors. I have also worked on a couple of projects in the past that dealt with a lot of image processing. I will soon begin working on my Master's thesis and want to decide a...
  30. E

    Understanding the Phase Shift Formula in Stimulated Brillouin Scattering

    Good morning I need to ask about the exact formula for the phase shift used in stimulated Brillouin scattering especially in the phase shifter thank you
  31. tsuwal

    Need a suggestion for an assignment on fiber optics.

    I am finishing a course on Eletromagnetism and Optics. I am currently a physics student in the second year of university. I passed the final exam and now I'm supposed to do a work on fiber optics. Do you know any interesting problem that i could adress? It can be a hard one, I am supposed to...
  32. R

    Optical Home-Made Fiber Optics: Alternatives to Food Jelly?

    Hello. I know how to realize an homemade fiber optic using some food jelly. Are there other materials, at amateur grade; to replace jelly ? ( NB this item has to be used in high vacuum, and jelly is not convenient for this use)
  33. tsuwal

    Fiber optics: using continous variation refractive indexes hold light?

    My teacher said that instead of using a fiber optic made of just one material we could use a set of materials with progressively low refractive index to turn the light back in, like so: In the case of a continuous variation of refraction index, how can you do the math. Can you please show...
  34. F

    In fiber optics is the thickess of the cladding important?

    Hello Forum, a fiber optic cable has two components: a core and a surrounding layer called cladding. The core has an index of refraction n_cor sligthly larger than the cladding core c_clad. This allows total internal reflection to take place. The difference in index is small to avoid...
  35. A

    Fiber Optics - Absolute and decibel Power Gains

    Homework Statement Problem is very simple but the textbook used for this class is complete garbage and has confused me to no end. a) Convert the following absolute power gains (dBm) to decibel power gains (dB). 10^-3 dBm, 2^n dBm b) Convert the following decibel power gains (dB) to...
  36. M

    Velocity in fiber optics cable

    Homework Statement I'm taking an introduction course in optics and I came across this exercise which I can't find how to solve: "Two light pulses with different wave lengths 500 and 600 nm is sent into a 1 km long fiber. n(610 nm) = 1.399, n(600 nm) = 1.400, n(510 nm) = 1.448, n(500) = 1.45...
  37. N

    How should I understand the dispersion in fiber optics?

    Homework Statement What is the physical definition of this graph and the unit of dispersion? I know it is picosec/(km times nm), but I am not sure for what it refers to. Homework Equations The Attempt at a Solution I asked my mates for the meaning and I typed them on the right of...
  38. F

    How Effective Is a Fresnel Lens in Transporting Light Through Fiber Optics?

    Hello, I have a 12x12" fresnel lens and I want to place a 14mm diameter fiber optics cable at the focal point to transport the light ~2.5 ft. Would there be any heat loss? And what percentage of the light would exit the fiber optics? Thanks, Fritz Laun
  39. A

    Fiber Optic Illumination System Research: Calculating Power & Length

    Hello everyone, Am having a research about the use of fiber optics in illuminating a room for example by taking solar power. What are the formulas that are used in order to know how much length do we need and how many fibers we need in order to have for example the power of a 60 watt lamp...
  40. W

    Fiber Optics Project: Determining Refractive Index w/ Int.

    Hello everybody I have my project on "Determination of some parameters (mainly the refractive index)of an optical fiber using multiple beam interference" i need some data about : Fizeau fringes shape derivation of an optical wedge at transmition and reflection. any help..?
  41. Topher925

    Is working with fiber optics difficult?

    This isn't really an "engineering" question but I really didn't know where else to ask. I just want to know if any of you out there have experience working with fiber optic wires and how difficult they are to work with. Is there any special equipment involved if you are not going to be splicing...
  42. S

    Seeking fiber optics info - power transmission

    Hi, first time poster here. I am a mechanical engineer, and I am looking for information on using fiber optics to transport solar energy. There is a new field called daylighting, that uses solar energy for lighting during daylight hours. It uses a variety of gadgets to do this, and some...
  43. Loren Booda

    Can earthbound fiber optics replace communication satellites?

    With the threat of satellites being blown up, would fiber optics offer a practical alternative for communications or other applications?
  44. C

    Laser to be used in fiber optics

    Homework Statement Which of the following can / cannot be used for fiber optic communication. What is the general rule / cut-off (in terms of wavelength) for deciding ? Thank you. Choices (Laser type/wavelength, nm) Argon fluoride (UV) 193 Krypton fluoride (UV) 248 Xenon...
  45. T

    Simple Fiber Optics Communications System

    Hi, it would be great if someone could give me a conceptual explanation of how a simple circuit of fiber optics communication works, since this is where the world is, in a communications sense.
  46. S

    Looking for a fiber optics paper

    I found an interesting paper a few weeks ago, but I haven't been able to find it again. The paper concerned using an electro-optic (LiNbO3) phase modulator to generate bandwidth on a pulse, and then using a spatial light modulator to shape the bandwidth and get a nice clean compressed pulse...
  47. G

    C vs. Fiber Optics: Speed Comparison and Myths Debunked

    Is C less than 300,000 kph when traveling through fiber optic cable? Would a pulse of light travel any faster through a straight fiber optic than through a tightly coiled fiber of the same length? Thanks, Glenn