We report what are to our knowledge the first continuous observations of optical fiber solitons and nonsoliton pulses in the spectral domain. Using a novel optical time-resolved spectral reflectometer that measures the backscattered light spectrum, we directly observed (with 200-m spatial resolution) the propagation of ∼8.5-ps solitons and nonsolitons traveling down 5-km fibers. Spectral breathing and the recovery of the original spectral widths are clearly seen for higher-order solitons. Possible applications include in situ measurements of soliton parameters, fiber dispersions, and nonlinearities, experimental verifications of pulse propagation theories, and optical sensing.
© 1996 Optical Society of America
Original Manuscript: January 17, 1996
Published: July 15, 1996
Amikam Levanon, Yoichi Fujii, Stephen R. Friberg, and Takaaki Mukai, "Direct observation of soliton and normal pulse propagation by spectral domain reflectometry," Opt. Lett. 21, 1023-1025 (1996)