Photon number squeezing of spectrally filtered sub-picosecond optical solitons S. Spälter, M. Burk, U. Strößner, M. Böhm, A. Sizmann and G. Leuchs Europhys. Lett., 38 5 (1997) 335-340 Published online: 01 September 2002 DOI: 10.1209/epl/i1997-00248-2