For the first time a method for realizing macroscopic quantum optical
solitons is presented. Simultaneous photon-number and momentum squeezi
ng is predicted using soliton propagation in an interferometer. Extrac
tion of soliton pulses closer to true quantum solitons than their cohe
rent counterparts from mode-locked lasers is possible. Moreover, it is
a general method of reducing photon-number fluctuations below the sho
t-noise level for nonsoliton pulses as well. It is anticipated that si
milar reductions in particle fluctuations could occur for other forms
of interfering bosonic fields whenever self-interaction nonlinearities
exist, for example, interacting ultracold atoms. [S0031-9007(98)07605
-4].