Generation of controllable nondiffracting beams using multimode optical fibers

Abstract

A method of generating nondiffracting beams using multimode optical fibers is reported. When a large-core multimode fiber is spliced onto a piece of single-mode fiber, only linearly polarized $\left(L{P}_{0,n}\right)$ modes are excited inside the multimode fiber segment because of mode orthogonality and on-axis excitation. Since the excited $L{P}_{0,n}$ modes are actually Bessel fields with different transverse wave vectors truncated by the core of the multimode fiber, the beam exiting the multimode fiber facet can form a variety of readily controllable and nearly nondiffracting optical patterns resulting from interference of apertured Bessel fields.