angular momentum (OAM) multiplexing is studied. We discuss the effect of atmospheric
turbulence to OAM-multiplexed FSO channels. We numerically simulate the propagation of
OAM-multiplexed beam and study the secrecy capacity. We show that, under certain
conditions, the OAM multiplexing technique provides higher security over a single-mode
transmission channel in terms of the total secrecy capacity and the probability of achieving a …