Quantum noise in optical fibers. II. Raman jitter in soliton communications

The dynamics of a soliton propagating in a single-mode optical fiber with g ain, loss, and Raman coupling to thermal phonons is analyzed. Using both so liton perturbation theory and exact numerical techniques, we propose that i ntrinsic thermal quantum noise from the phonon reservoirs is a larger sourc e of jitter and other perturbations than the gain-related Gordon-Haus noise for short pulses (less than or similar to1 ps), assuming typical fiber par ameters. The size of the Raman timing jitter is evaluated for both bright a nd dark (topological) solitons and is larger for bright solitons. Because R aman thermal quantum noise is a nonlinear, multiplicative noise source, the se effects are stronger for the more intense pulses that are needed to prop agate as solitons in the short-pulse regime. Thus Raman noise may place add itional limitations on fiber-optical communications and networking by use o f ultrafast (subpicosecond) pulses. (C) 2001 Optical Society of America OCI S codes: 060.4510, 270.5530, 270.3430, 190.4370, 190.5650, 060.2400.