Generation of quantum correlation between co-propagating pulses in optical fibers

Experimental demonstration of more than 50% photon-number squeezing obtained using microstructure fibers (MFs) , of which zero-dispersion wavelength locates at 820 nm, in a spectral filtering scheme with 40-fs laser pulses at λ = 810 nm is reported. The highest photon-number squeezing of -4.6 dB is obtained when a soliton-like Stokes Raman pulse, which broke up from the main pulse, exhibiting a self-frequency shift toward the longer wavelength, is preserved by low-pass spectral filtering from the white-light spectrum generated from the 30-cm MF.