Refractive and absorptive optical nonlinearity can be distinguished using a pump–probe interferometric technique with picosecond time resolution. The method is applied to both resonant and nonresonant nonlinearities in optical fibers and reveals marked differences between the relaxation behavior of the refractive and absorptive nonlinearity certain cases. A monomode fiber doped with CdSxSe1−x semiconductor nanocrystals exhibits a large optically in induced phase shift with ~10-psec relaxation time, which is many orders faster than the relaxation of the absorptive nonlinearity under identical conditions.
© 1989 Optical Society of America
Original Manuscript: June 13, 1988
Manuscript Accepted: January 3, 1989
Published: March 15, 1989
D. Cotter, C. N. Ironside, B. J. Ainslie, and H. P. Girdlestone, "Picosecond pump–probe interferometric measurement of optical nonlinearity in semiconductor-doped fibers," Opt. Lett. 14, 317-319 (1989)