Cross-phase modulation and multiwavelength adiabatic solitons

In an experimental demonstration of four-channel, wavelength-division-multi plexed repeaterless transmission over 235 km, adiabatic soliton propagation allows for precise spectral characterization of cross-phase modulation eff ects during initial soliton collisions. Theoretical predictions of the spec tral shifts that occur are verified for ultrashort solitons. The relationsh ip between the frequency shift and the initial pulse separation is confirme d by measurement of the bit-error ratio as the pulse spacing is varied at t he fiber input. Adiabatic expansion of narrow solitons may help to alleviat e the channel restrictions that are required for prevention of soliton coll isions at the fiber input. (C) 2000 Optical Society of America.