Ultrashort Optical Pulse Squeezing in Nonlinear Fibers.

Concepts and experimental works of ultrashort optical pulse squeezing in nonlinear fibers are reviewed. In a nonlinear fiber, optical fields are squeezed or quantum mechanically correlated by optical Kerr effect. These are, however, unobservable by direct photo-detection. Three kinds of strategies to extract the detectable squeezing have been proposed and implemented experimentally. Recent studies on applications of these squeezed pulses or the intrapulse quantum correlations to the generation of entangled states are also reviewed.