Alexeyev, A.N.; Fadeyeva, T.A.; Volyar, A.V.; Soskin, M.S.
(Semiconductor Physics Quantum Electronics & Optoelectronics, 1998)
The problem of propagation of optical vortices in multimode fibers is considered. The structural changes experienced by the wave and ray surfaces in their transformation from the free space to a fiber medium are determined. ...