Quantum fiber-optics: some recent experimental and theoretical developments

Convenient methods of generating amplitude-squeezed (sub-Poissonian) light have recently been discovered, which rely on the use of soliton-like pulses in fibers. The idea of squeezing solitons in fibers is; what is new, however, is the use of femtosecond pulses in conjunction with asymmetric Sagnac loops. Since femtosecond solitons have a correspondingly high peak power, much shorter fiber lengths are required to obtain a given amount of squeezing, which directly translates into lowering of the guided acoustic-wave Brillouin scattering noise in the system. The use of an asymmetric Sagnac loop leads to a robust, practically very stable configuration for generating amplitude squeezing. In a related development, spectral filtering of femtosecond solitons emerging from a straight piece of fiber has also been shown to generate sub-Poissonian light.