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Fiber Optics

  1. Feb 29, 2008 #1
    Why is it that we are able to use a laser beam with optical fiber but not with a white light source?
  2. jcsd
  3. Feb 29, 2008 #2
    We need lights with monowavelength
  4. Feb 29, 2008 #3

    Andy Resnick

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    I'm not sure what you mean- I couple a halogen light and a Mercury arc lamp into a fiber on my microscope.

    There are many kinds of fibers- single mode, multimode, light guides, bandgap, polarization-maintaining, etc. etc. etc.

    A single-mode fiber is what most people associate with "optical fiber", and single-mode means a single transverse mode, which restricts the waveband. Multimode fibers can support a much broader waveband range, light guides (what I use with the halogen bulb/arc lamp) are not much more than "light pipes", and photonic bandgap fiber is really cool.

    There's some technical issues with how to couple the light into a fiber, but it's sort of possible to couple nearly any source to any fiber- what light actually propogates down the fiber will depend on the fiber.
  5. Feb 29, 2008 #4
    Thank you pixel01 and Andy Resnick. I understand better now :)
  6. Mar 1, 2008 #5


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    Welcome to PF, Chickenlittle.
    I have to assume here that you're refering to information transmission. Any kind of light will propogate through an optical fibre, as you can easily see by looking at a fibre optic lamp. A modulated source is needed for any sort of information transfer. You can transmit Morse code just by turning a light bulb on and off. For the complexity of high-speed digital transfer, a coherent source is more readily controllable and more accurate.
  7. Mar 2, 2008 #6

    Claude Bile

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    It is also much easier to couple light into a fibre (with efficiency) using a laser source that it is with using other types of sources.

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