Pump-probe collision in optical fibers: four-wave-mixing induced frequencyjump

An investigation is made of ultrafast pump-probe pulse collisions near the zero-dispersion wavelength in an optical single-mode fiber. A steplike prob e frequency shift is observed when the pump power is gradually increased. T he magnitude of this frequency jump is shown to depend on the phase differe nce between the pulses. This new effect is investigated numerically and exp erimentally and is attributed to four-wave mixing. (C) 2001 Optical Society of America.