In this article it is shown that for specific initial conditions an input beam injected in a multimode periodic segmented waveguide does not diffract and remains collimated all along the waveguide, whereas a speckle-like pattern is expected at the output of a multimode structure. This nonintuitive behavior can be explained with the help of ray and wave chaos properties. A modal analysis developed in this article reveals that this nondiffractive beam regime is due to a specific superposition of modes with regularly spaced propagation constants. A discrepancy with the commonly used equivalent continuous waveguide model is also identified.
© 2013 Optical Society of America
Original Manuscript: July 17, 2013
Manuscript Accepted: October 8, 2013
Published: November 8, 2013
Pierre Aschiéri and Valérie Doya, "Snake-like light beam propagation in multimode periodic segmented waveguide," J. Opt. Soc. Am. B 30, 3161-3167 (2013)