Comparing mode-crosstalk and mode-dependent loss of laterally displaced orbital angular momentum and Hermite-Gaussian modes for free-space optical communication

作者：Ndagano Bienvenu; Mphuthi Nokwazi; Milione Giovanni^*; Forbes Andrew

来源：Optics Letters, 2017, 42(20): 4175-4178.

DOI：10.1364/OL.42.004175

There is interest in using orbital angularmomentum (OAM) modes to increase the data speed of free-space optical communication. A prevalent challenge is the mitigation of mode-crosstalk and mode-dependent loss that is caused by the modes' lateral displacement at the data receiver. Here, the mode-crosstalk and mode-dependent loss of laterally displaced OAM modes (LG(0,+1), LG(0,-1)) are experimentally compared to that of a Hermite-Gaussian (HG) mode subset (HG(0,1), HG(1,0)). It is shown, for an aperture larger than the modes' waist sizes, some of theHGmodes can experience less mode-crosstalk and mode-dependent loss when laterally displaced along a symmetry axis. It is also shown, over a normal distribution of lateral displacements whose standard deviation is 2x the modes' waist sizes, on average, the HG modes experience 66% less mode-crosstalk and 17% less mode-dependent loss.

• 出版日期2017-10-15