Optical Fibres

Discussion in 'Physics' started by aliashar86, Jan 25, 2007.

  1. aliashar86

    Thread Starter Active Member

    Nov 23, 2006
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    plz explain in simple n few words the concept of optical fibres in connection with total internal reflection.
     
  2. aliashar86

    Thread Starter Active Member

    Nov 23, 2006
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    How is the "Index of refraction of material through Prism" determined by the relation :

    nm = [Sin (A+Dm)/2]
    --------------
    [Sin (A/2)]
     
  3. aliashar86

    Thread Starter Active Member

    Nov 23, 2006
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    Why Dm i.e., minimum angle of deviation is taken here why not <D.
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    At the boundry between two materials (glass and air) a beam of light can do one of two things. It can be reflected at the boundry with the angle of reflection equal to the angle of incidence. It can also pass through the boundry and be refracted (bent) as it does so.

    In total internal reflection the amount of light which escapes from the fiber is idealy zero.
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
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    Are these schoolwork questions? If so, we can move this thread to the appropriate forum. If they're just musings or such, please ignore my post.
     
  6. alitex

    Active Member

    Mar 5, 2007
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  7. thingmaker3

    Retired Moderator

    May 16, 2005
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  8. DrNick

    Active Member

    Dec 13, 2006
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    Optical fibiers are just dielectric waveguides. Since the intrinsic impedance of the medium (the fiber) is higher than that of air, total internal reflection confines the wave (ie light) in the fiber. Outside of the fiber evenescent waves propagate, giving an exponentially decaying solution that is determined from the boundry conditions.
     
  9. thingmaker3

    Retired Moderator

    May 16, 2005
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    At least until you kink that sucker real good!:D
     
  10. alitex

    Active Member

    Mar 5, 2007
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    dear waht do u mean about "404 dude"?????
     
  11. alitex

    Active Member

    Mar 5, 2007
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  12. Dave

    Retired Moderator

    Nov 17, 2003
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    HTTP 404 error

    Dave
     
  13. DrNick

    Active Member

    Dec 13, 2006
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    The link produces a 404 error (document does not exist)..
     
  14. Ashraf Ali

    New Member

    Nov 2, 2007
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    optical fibers are jus wave guides, basically they have a core (the actual guide) and a cladding surrounding it, the fiber uses Total Internal Reflection (TIR) as its principle for transmission of the intensity, TIR will occur if the refractive index of the cladding is lower than the core, the angle of incidence is greater than the critical angle (minimun angle below which TIR will not occur), and the incident intensity must be well with in the acceptance cone of the fibre. when these parameters are met TIR occurs and the wave is propogated through.
     
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