Laser applications and other topics in quantum electronics

Phenomenon of switching of the sign of a wavefront dislocation in a bent few-mode optical fibre

M. A. Bolshtyanskii

Chelyabinsk State University

Abstract: Switching of the sign of a wavefront dislocation as a result of bending of a few-mode optical fibre is predicted and confirmed experimentally. The switching effect is based on the dependence of the phase velocities of the modes in a fibre on its bending. Mode interference at the fibre output creates a wavefront dislocation with parameters which can be controlled by the fibre shape. An increase in the fibre curvature transforms a linear dislocation into a circular one with a specific sign, back into a linear one, then into a circular one with the opposite sign, etc. The frequency of alternation of the dislocation sign, resulting from the change in the bending radius, is shown to agree with theoretical estimates.

PACS: 42.81.Dp, 42.65.Sf

Received: 01.01.1996

 English version: Quantum Electronics, 1996, 26:7, 647–650

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