Mode sorting performance for optical beams carrying orbital angular momentum suffering lateral displacement and angular deflection

Beams carrying orbital angular momentum (OAM) is expected to be a new degree of multiplexing to increase transmission capacity in the optical communication. Mode sorting methods have been reported so far as efficient ways to demultiplex such OAM multiplexed lightwaves. Since the OAM transmission is mainly through free-space, the transmitting OAM lightwave may suffer lateral displacement and angular deflection on the receiver plane. In this paper, we numerically investigate the tolerance to lateral displacement and angular deflection on the mode sorting performances for beams carrying OAM. Comparing the performance in terms of crosstalk in between high resolution and ordinary resolution mode sorting methods reveals that the high resolution one shows a slight lower crosstalk while almost the same tolerance as the ordinary resolution one.