What is Fiber optic: Definition and 43 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. 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...
  2. Oldman too

    Dark fiber optic cables as Earthquake detectors

    Hello, Recently while familiarizing myself with the rodent menace affecting Fiber optic networks, I came across this rather novel use for the dark, or unused fibers in buried cables. The method apparently holds a lot of promise as well as significant advantages over many current Seismology...
  3. B

    Coupling Efficiency of LED to Fiber Optic Guide

    Most surface mount types of LED’s have a very nearly cosine distribution of light intensity. If we desire to inject light from an LED to the end of a cylindrical optical guide, what is the coupling efficiency as a function of distance (x) from the end of the guide? Assume that the LED is a...
  4. S

    Polarization of elliptical fiber modes

    If I have three modes in an optical fiber with elliptical facet as shown in the figure, what would be the polarization direction of the modes... what I know that it is linear polarization and could have several configuration.. but what I want really to know that if could be a situation where the...
  5. A

    Anyone familiar with SFP Fiber Optic Modules?

    I have a question regarding the minimum operating speed of new SFP+ fiber modules. In my line of work, I'm most commonly seeing 10GBASE SFP+ modules installed for network data. Can these modules operate at low speed? Specifically with a PHY capable of only a fraction of the data rate? Further...
  6. S

    A Does the Silicon Nitride Waveguide Have a Cladding?

    Does the Silicon Nitride Waveguide (Si3N4) has a cladding ?! I read an article that they use the evanescent field of silicon-nitride waveguide.. If the answer yes it doesn't has a cladding then can I say that the evanescent field length in the surrounding medium is the mode field portion in that...
  7. S

    A Mode Field Diameter and Penetration depth of the Evanescent field

    Source: fobasics.blogspot.com Source: scirp.org As it is shown in the first pic above that the mode field diameter is defined as the mode field decreases to 1/e (in intensity 1/e^2), if I take the mode field and subtract the core's diameter then I divide it by 2, should I get the penetration...
  8. C

    Quantum Computer Security

    I was wondering, I recently discovered, but don't have the article, that there is a security technology that involves the superposition of photons across a fiber optic link. I was wondering could a glass register more adequately create a quantum computer for peoples usage than an actual atomic...
  9. S

    Does Light Travel Through Fiber Optic Cable Generate EMF?

    Does light traveling through a fiber optic cable generate any sort of detectable electromagnetic field? Please forgive the stupid question. It’s something that popped into mind recently and google hasn’t adequately answered for me. I’m not a scientist or physicist. :blushing:
  10. D

    Bend in a fiber optic cable

    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.
  11. DaveC426913

    Competing fiber optic corps

    Just doing due diligence to allay some concerns. If my condo already has Rogers fibre optic cable, and my condo org wants to come in and install a Bell Fibe cable for the hole building, is there any reason to think that this would interfere with the existing Rogers cable? I mean, they're...
  12. Jamison Lahman

    Fiber Optic Coupling -- how to couple a 200μm core fiber into a 50μm core fiber?

    Is it possible to couple a 200μm core fiber into a 50μm core fiber by using a 4x magnifier/reducer?
  13. C

    Danger from damaged fiber optic cable?

    Hi all, I was not sure where to post this, so feel free to move the thread if the forum is not the most appropriate. I was reading about safety in fiber optics and the fact that one should not be staring into a fiber optic cable to avoid eye damage. That's pretty obvious, but it also raises a...
  14. I

    Optics Question -- small glass spheres to couple to fiber optic cables

    Homework Statement Homework Equations I know that yin = 0.7mm, y2 = 0mm, the index of refraction for the sphere is 1.8 and the indices of refraction for the air surrounding it is 1. The Attempt at a Solution Not sure how to even begin with the given information. I was thinking I could...
  15. D

    Fiber Optic Loop: How Long Before Photon Dissipation?

    Imagine a closed loop of fiber optics, How long will a photon be able to stay inside the loop before dissipating all it's energy, or does it not dissipate?
  16. P

    BPSK Fiber Optic Communication technique module.

    Actually out of my personal interest to learn & upgrade my skills I have self volunteered self development of Photonics Simulation software on Python platform. I am basically a software developer. As such I seek some technical information for same related to its development activity. Can you...
  17. I

    Fiber Optic Gyros: Accuracy & Price | Camera/Gun Stabilization

    Hello every body. Has anybody used Fiber Optic Gyros? How accurate they are? How about the price range? Could anybody help me select a suitable actuator system/motor mechanism for, say a camera stabilization or a gun stabilization using a fiber optic gyro. I want to get rid of mechanical gyros.
  18. J

    How are fiber optic cables affected with time?

    Does anyone know of some good references regarding how fiber optics are effected while aging in the field? What determines the life span of a fiber installation? Specifically, what causes the signal quality to degrade, and how quickly does it degrade. (That is, how does the attenuation across...
  19. A

    Total internal reflection inside a fiber optic cable

    Homework Statement A multi-mode fiber optic cable has a core diameter d = 115 mm, ncore = 1.42, and ncladding = 1.17. What is the largest possible angle θin relative to the surface normal that light can enter the fiber (i.e. pass from air into the fiber core) and experience total internal...
  20. J

    How does a single fiber optic cable transmit millions of signals

    That's how the internet works across oceans, correct? I understand how a fiber optic cable transmits information, but how does it transmit everybody's information at once in just one dollar coin sized cable? One after the other? I find that hard to believe given how fast the internet is, even at...
  21. Z

    Fiber Optic Cable Capacity

    I am trying to design a system that will carry light for illumination along a fiber optic cable. I see that there are many thicknesses of fiber optic cable - however I am unsure of the purpose of this. I've never heard of a 'density' of light that you can put into a cable - is there such a...
  22. F

    Modes and numerical aperture of a fiber optic cable

    Hello Forum, the numerical aperture NA of a fiber optics is given by the square root of the squared core index minus the squared cladding index. The NA indicates the angular ability to collect light from the outside of the fiber, i.e. the max semi-angle over which light will enter the fiber...
  23. P

    Fiber Optic Y Connection Question

    Is it possible to have a fiber optic wire spliced onto another (or starting from 3 separate fibers) to form a Y shape and have loss-less (or close thereto, as good as a normal splice) transmission from 2 of the fibers into the third? I know this wouldn't work for double-clad fiber or for...
  24. D

    Fiber Optic Interconnects to transfer data

    Has anyone use fiber optic interconnects in their computers? I read an article suggesting that this is the way to go to move data really quickly, and it got me interested. My google search's have primarily just resulted in company's trying to sell connectors, etc. etc... Any actual...
  25. N

    Fiber Optic PPR biochemicals detection sensor

    I was reading this journal on FO-PPR sensor and had a doubt. Couldn't exactly google for an answer as it was unclear. "Integration of fiber optic-particle plasmon resonance biosensor with microfluidic chip" by a group of scientists. I have attached the pdf. Under the section "Preparation of...
  26. S

    Fiber optic current sensors

    Hello..I'm a undergrad student from hyderabad ,India. Presently I'm am doing a theory based research project on fiber optic current sensors ..which are mainly used to sense current in substations . Recently i got a paper when i googled on the net. It was titled Temperature and Vibration...
  27. S

    Fiber optic current sensors

    Hello seniors..im a undergrad student from hyderabad ,India. Presently I am am doing a theory based research project on fiber optic current sensors ..which are mainly used to sense current in substations . Recently i got a paper when i googled on the net. It was titled Temperature and...
  28. H

    Light Traveling in both Directions in a fiber optic cable

    We have a spectrometer in our lab that collects light through a fiber optic cable, however it also sends a 532nm laser down this fiber optic cable. My background isn't in optics, and it would seem to me that the returning light (which is typically around 694 nm) would interfere with each...
  29. S

    Help Finding a Simple Fiber Optic Sensor for Pressure/Temp Measurement

    hello can someone suggest a simple fiber optic pressure/temperature sensor that can be constructed ...with reasonable accuracy and less equipment... i came across a few papers about the same...but not sure about the scale and precision required... please help thanks
  30. R

    Sending Laser Light out of fiber optic in all directions

    I currently have a laser set up that sends three lasers (red, yellow, green) into an optical fiber. On the other end of the fiber, the emitting light is shooting in essentially one forward direction. Does anyone have any suggestions or a suggestion on a certain material that if put on the end...
  31. R

    Increase Laser Power out of fiber optic

    I am working on a project and am combining three laser beams in an effort to make artificial white light out of the end of the fiber. It is currently producing about 1 mw of power. How could I increase the power out of the end of the optical fiber?
  32. B

    Calculate optical path in SELFOC cylindrical fiber optic

    Hi. This is my first message in this forum. I'm not English, so sorry my spelling. Homework Statement Calculate the optical path done by a meridional ray, supposing it covers a horizontal distance, d, in z-axis direction. \gamma_0 is the launch angle (with z-axis).Homework Equations Optical...
  33. B

    Fiber Optic Cleaning Systems

    Can anyone describe basic inspection techniques and processes of cleaning for fiber optic cables
  34. J

    Optical Path length in core fiber of fiber optic faceplate

    Homework Statement Sorry if this is the wrong section. Please redirect me if there is a more appropriate one. I'm looking at the timing spread in the time of flight of photons through fibers in a fiber optic faceplate. Essentially the minimum time for photons to propagate through one of the...
  35. D

    Searching for Fiber Optic Information? Look No Further!

    Does anyone know of any links to some good fiber optic information? I'm not looking for suppliers or sales pitches...rather something like www.Microwaves101.com , but for fiber optics... Other than arguments on comparisons, I haven't found too much in PF. Thanks.
  36. N

    Refraction and fiber optic cable diameter

    Hello there, I'm wondering if there is any restricting reason why fiber optic cables are not made thicker. Regardless of the practical applications, is there any reason you can't make a fiber optic cable that is only 2m long but 2cm thick (compared to the normal 0.0125 cm thick)? Does width of...
  37. T

    Fiber optic internet connection?

    In a few days, people from my ISP are coming to my house to install super-fast fiber optic internet. Right now, I am using a DSL, or about a 3-meg connection speed. According to what I've heard, a fiber-optic network connection can give up to 20 megs. I use my computer for gaming, especially...
  38. hxtasy

    How do fiber optic pressure sensors work?

    In a nutshell? i cannot seem to find a lot of information online about these. Could someone please help? thanks!
  39. K

    Fiber optic based beam splitter

    Hi, Does any of you know any commercially available fiber optic - beam splitter? It is very crucial for my experiment where I distribute an electromagnetic beam from one laser source (infrared) to two waveguides.. Since I am coupling using fibers, I require a fiber optic based beam...
  40. J

    Fiber optic coupling question

    I hope this post in the appropriate forum. I have a spectrograph and a CCD imaging chip that I am using for an optics experiment. The light coming into the spectrograph is through a 10 micron fiber optic. In order put the light on the CCD imaging chip the way I want it, I believe I need to...
  41. K

    About fiber optic refraction

    Question: A ray of light enters a light fiber at an angle of 15degree with the long axis of the fiber. Calculate the distance the light ray travels between succesive reflections off the sides of the fiber has an index of refraction 1.6 and is 10^{-4}mm in diameter.
  42. T

    Going completely fiber optic computers

    So, because light is so fast and fiber optic cables can carry 3 different signals at at time and travel at the "speed of light"; why don't we have the technology to develop a computer that uses all fiber optics instead of wires or optics and wires (if your lucky) I'm sure that if we did know...
  43. C

    Fiber Optic Cabling: SC & ST Connectors Explained

    Does anybody know what the SC and ST connectors stand for [?] thanks joe
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