"Vortex modes" carrying orbital momenta may be created in optical fibers by superpositions of fiber modes. Slight fiber core asymmetries destabilize the linear vortex modes during their propagation but the nonlinear effects can stabilize them.
© 2005 Optical Society of America
B. Burgoyne, N. Godbout, and S. Lacroix, "Nonlinear Stabilization of Modes with an Orbital Momentum in Optical Fibers," in Nonlinear Guided Waves and Their Applications, Technical Digest (CD) (Optical Society of America, 2005), paper ThB11.
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