Reversible conversion between optical frequencies of probe and idler waves in regime of optical event horizon

The controlling optical frequency in the regime of an optical event horizon by the collision between a soliton and a probe pulse is investigated, and the process by which the probe is converted into the generated pulse (idler) with new optical frequency is reversible. For the two cases in which the probe wave interacts with a bright/dark soliton, a unified analytical formula governing the reversible frequency conversion process is derived that can predict the frequency of the idler very well. This reversible frequency-conversion process is validated by cascaded four-wave mixing (FWM) triggered by a set of quasi-CW fields, strongly suggesting that the process arose from cascaded Bragg scattering. It establishes a link between the nonlinear interactions of a soliton with the probe and FWM of monochromatic quasi-CWs. (C) 2016 Optical Society of America