OBSERVATION OF OPTICAL SOLITON PHOTON-NUMBER SQUEEZING

We report the photon-number squeezing of optical solitons. 2.7 ps puls es were launched as solitons down a 1.5 km optical fiber. For energies slightly above that of fundamental solitons, they broadened spectrall y due to self-phase modulation caused by chi((3)) nonlinearities. Filt ering away outlying components of the broadened spectra squeezed the s oliton's photon-number fluctuations to 2.3 dB (41%) below the shot-noi se limit. Accounting for losses, this corresponds to 3.7 dB (57%) phot on-number squeezing. A quantum field-theoretic model shows that the ou tlying spectral components have large energy fluctuations, so that the ir removal causes squeezing.