Analysis of aperture size for partially receiving and de-multiplexing 100-Gbit/s optical orbital angular momentum channels over free-space link

In this paper, we present a free-space link utilizing orbital angular momentum (OAM) multiplexing, where only a proportion of the beam is received. Partially receiving an OAM mode could lead to crosstalk between neighboring modes. Here, we analyzed the effect of the aperture size on the system crosstalk both numerically and experimentally. We also demonstrated an optical data link with a total capacity of 200 Gbit/s using receiver with partial aperture. Bit error rate (BER) performance of the partial receiver is measured for different receiver aperture sizes.