1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Refraction and fiber optic cable diameter

  1. Dec 16, 2009 #1
    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 the high index core make a difference, and does the width of the low index coating make a difference in regard to total internal reflection?

    To sum it up, is there any physical reason why fiber optic cables can't be made thicker?

    Thanks for reading,
    JJ
     
    Last edited: Dec 16, 2009
  2. jcsd
  3. Dec 16, 2009 #2

    berkeman

    User Avatar

    Staff: Mentor

    Welcome to the PF. Are you aware of the differences between single-mode and multi-mode fiberoptics?

    http://en.wikipedia.org/wiki/Fiber_optics

    And are you aware of the concept of "dispersion", where the path lengths for multi-mode fibers (especially as wide as you are asking about) indroduce different delays for different ray traces? What effect would dispersion have on high-bandwidth optical signals?
     
  4. Dec 16, 2009 #3
    Thanks for answering and good points berkeman,
    I am not particularly concerned with transmitting data or signals, and so I believe that dispersion wouldn't play a bad role as long as the light was a guided ray the whole time. You could say that I want to be able to use the fiber optic cable like a snake light, where you could put light in one end of the cable and receive light out of the other end, like an extension cord for a flash light. I believe the thickness would require multi-mode, it would allow more light sources can be used.
     
  5. Dec 16, 2009 #4

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Light pipes are different than fibers. Fibers are (usually) significantly longer- many kilometers- for one thing.
     
  6. Dec 16, 2009 #5

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If you want a thicker fiber optic, just bundle up a bunch of smaller ones.
     
  7. Dec 16, 2009 #6
    That could possibly work. A light pipe (Thank you Andy Resnick) is what I believe the term is what I am looking for.
     
    Last edited: Dec 16, 2009
  8. Dec 16, 2009 #7

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    It depends on the application- do you need it to be flexible? Are you trying to image?

    Liquid light guides have diameters up to 8 mm. I've seen rigid light guides with diameters over 2 inches, but I don't recall who made them.
     
  9. Dec 16, 2009 #8
    I'm not trying to image, just pass light from a flashlight into one end and out the other to be used for light to see. Rigid works, flexible is better. Light guides are the closest I've seen so far. I can adapt from the light guide concept and go from there.
    Thanks for pointing me in the right direction Andy.

    This is what I was looking for.
    http://www.lumatec.de/e_superlite/e_superlite.htm [Broken]
     
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook