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!

Group Velocity Dispersion

  1. Feb 1, 2015 #1
    1. The problem statement, all variables and given/known data
    Our lecturer seemed to skip over how to get from the Group Velocity Dispersion to the actual temporal stretch of a pulse sent down an optical fibre, instead we were given just the two formula. I've been trying to work out where the temporal stretch comes from but can't work it out.

    2. Relevant equations
    The GVD in this case is given by
    $$ GVD = \frac{dv_g}{dk} = -\frac{\omega}{n}\frac{d^2n}{dk^2}=-\frac{\omega}{n}\frac{\lambda^4}{4\pi^2}\frac{d^2n}{d\lambda^2}$$

    The temporal stretch is given by
    $$ \Delta\tau = -\frac{L}{c}(\lambda^2\frac{d^2n}{d\lambda^2}) \frac{\Delta\lambda}{\lambda} $$
    3. The attempt at a solution
    Have made very little progress, only got as far as getting the same factors as in the temporal stretch.

    $$ GVD = -(\lambda^2\frac{d^2n}{d\lambda^2})(\frac{\lambda^2}{4\pi^2}\frac{\omega}{n})$$
  2. jcsd
  3. Feb 1, 2015 #2
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted