Mode-Division Multiplexing of 2 $\,\times\,$100 Gb/s Channels Using an LCOS-Based Spatial Modulator

We demonstrate one of the first experiments of optical transmission based on mode-division multiplexing over a few-mode optical fiber. The mode multiplexer and demultiplexer are based on a programmable liquid crystal on silicon panel. Using this system, we transmit two 100 Gb/s polarization division multiplexed quaternary phase-shift keying data streams modulated on two different modes of the prototype few-mode fiber. At the receiver, a set of optical coherent detectors with DSP including multiple-input multiple-output algorithms recover the signal and permit to mitigate the crosstalk stemming from imperfect mode conversion.