Liquid-crystal-on-silicon-based optical add/drop multiplexer for orbital-angular-momentum-multiplexed optical links

We designed an optical add/drop multiplexer for orbital-angular-momentum (OAM)-multiplexed data links by taking advantage of the ring-shaped intensity profile of OAM beams. We demonstrated adding/dropping a single OAM beam from three multiplexed OAM beams using liquid-crystal-on-silicon-based diffraction optical elements. For multiplexed OAM beams carrying $100\mathrm{Gbit}/\mathrm{s}$ quadrature phase-shift-keying data, a power penalty of $<2\mathrm{dB}$ is observed to achieve a bit-error rate of $2.0\times {10}^{-3}$ for each channel of the add/drop multiplexer.