| Abstract: |
Optical fibers designed to support multiple transverse modes offer opportunities to study wave
propagation in a setting that is intermediate between single-mode fiber and free-space propagation.
A variety of qualitatively-new phenomena have been observed recently in multimode fibers. Self-cleaning of a multimode beam is observed at a fraction of the critical power for self-focusing, and without loss. New instabilities, which are spatiotemporal in nature, occur. By varying the launched
spatial modes, it is possible to generate dispersive waves over an octave in frequency, megawatt pulses in
the near infrared, or continua that span multiple octaves.
After a tutorial introduction to nonlinear wave propagation, one or two of these phenomena will be
presented along with their connection to multimode soliton dynamics. Recent progress in spatiotemporal
mode-locking in fiber lasers will then be summarized. The variety of 3-dimensional lasing states appears
to open many opportunities for future study .
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