Multicasting in a spatial division multiplexing system based on optical orbital angular momentum.

We report multicasting data from a single orbital angular momentum (OAM) spatial channel onto multiple OAM channels of equally spaced OAM charge numbers. The designed sliced phase patterns for multicasting are loaded on the spatial light modulator. By optimizing the design of the phase pattern, the power of multicasted OAM channels can be equalized. We experimentally demonstrate multicasting five and seven OAM channels from a single-input OAM channel carrying a 100  Gbit/s quadrature phase-shift keying (QPSK) data stream.