2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89107The consistent quantum theory of self-phase modulation (SPM) and cross-phase modulation (XPM) for ultrashort light pulses (USP) in medium with electronic Kerr-nonlinearity are developed. The approach makes use of momentum operator of electrical field which takes account of the inertial behaviour of the nonlinearity. The spectrum of quantum fluctuations of squeezed-quadrature component as a function of response time of nonlinearity and values of nonlinear phase shifts due to the SPM and XPM effects, is investigated.8 pages, LaTeX, style file included, 1 .eps figure. Talk given at QCM & C 2000 (Capri, Italy). To appear in "Quantum Communication, Measurement and Computing 3" (Kluwer Acad. Plen.Publ. NY). New interpretations of previous e-printsQuantum Physicstext