Self-focusing was observed at Raman frequencies, using picosecond pulses propagating in a large-core optical fiber of 100-μm diameter. For intense input pulses, a continuum of Stokes frequencies was generated in a small ring-waveguide structure. The ring diameter of 11 μm was about 10 times smaller than the beam diameter at low intensities. The ring structure was attributed to an induced-gradient-index profile arising from the nonlinear index of refraction.
© 1987 Optical Society of America
Original Manuscript: March 27, 1987
Manuscript Accepted: May 14, 1987
Published: August 1, 1987
P. L. Baldeck, F. Raccah, and R. R. Alfano, "Observation of self-focusing in optical fibers with picosecond pulses," Opt. Lett. 12, 588-589 (1987)