title: Mode volume
text: # Mode volume
  
  In fiber optics, mode volume is the number of bound modes that an optical fiber is capable of supporting.
  
  The mode volume M is approximately given by $V^{2} \over 2$ and ${V^{2} \over 2}\left({g \over g+2}\right)$, respectively for step-index and power-law index profile fibers, where g is the profile parameter, and V is the normalized frequency, which must be greater than 5 for this approximation to be valid.
  
  