'Cherenkov' Radiation

Cherenkov radiation is light emitted from a charged particle passing through a dielectric medium at a speed greater than the phase velocity of light in that medium.

In optical fibers, however, this name has been given to a radiation band that corresponds to an instability of a soliton due to higher order dispersion. The light emitted from the soliton lies between the ultraviolet and the infrared, depending on the soliton wavelength and fiber dispersion. In fibers this dispersive radiation has a higher phase velocity than the soliton.

Cherenkov radiation in fibers is an efficient and flexible wavelength conversion process providing tunable pulsed light throughout the visible spectrum and beyond. Moreover, this radiation is related to, but distinct from the radiation emitted from artificial event horizons in fibers. Its investigation can provide insights into the physics of wavelength conversion and amplification by fast moving index perturbations.