fiber = CFiberFromBeta2(sUniqueName, vAngFreq, vBeta2)
 
  Creates a fiber material with dispersion defined by discrete 
  dispersion data
 
  sUniqueName the friendly name of the material
  vAngFreq is the "real" (not relative - not the frequency detuning)
     angular frequency in Hz (Hertz).
  vBeta2 are the values of dispersion (d^2 k / d omega^2) in
     s^2/m (seconds^2 per meter).
 
  the refractive index of the fiber is composed by 
  interpolation/extrapolation of the discrete data 
  completed by the k_0 and k_1 of fused silica
  completing the refractive index with k_0 and k_1 
  has no influence on propagation of single polarization