- #1
Jeffrey Yang
- 39
- 0
I just read some words from the book Optical Waveguide Theory by Snyder, Allan W., p226. It says that
"However, although it is possible for the phase velocity of a mode to exceed the maximum speed of light in the cladding (of waveguide), c/n_cl, this cannot occur without losing power to radiation"
My question is how to understand this? Why losing power can increase the phase velocity of the wave?
"However, although it is possible for the phase velocity of a mode to exceed the maximum speed of light in the cladding (of waveguide), c/n_cl, this cannot occur without losing power to radiation"
My question is how to understand this? Why losing power can increase the phase velocity of the wave?