Selective excitation of vortex fibre modes using a spatial light modulator

A controllable excitation of fibre modes is examined theoretically and experimentally. We verify that the modes of a few-mode fibre can be selectively excited by means of a spatial light modulation of a laser beam focused to the fibre. The proposed method is demonstrated on a dynamical switching, phase coupling and weighted mixing of LP0111, LP (and LP)(21) modes, achieved by an exchange of computer-zgenerated holograms sent to the spatial light modulator. The possibility to excite a vortex fibre mode with a well-defined azimuthal phase dependence is also verified. It is promising for an encoding and transfer of information by vortices in fibre communications.