Multiuser-MIMO Transmitter Based on Optical Polar-Vector Modulators

We present the use of a novel optical modulator architecture to achieve simultaneous radiofrequency (RF) multi-user beamforming and data modulation. Optical vector modulators enable control of the complex state of a transmitted wave by directly and independently controlling both amplitude and phase. Operating in the optical domain affords extremely wide bandwidth and negligible dispersion in such modulators. A demonstration experiment is presented based on a 2-element transmit array, where the vector modulators were assembled from pairs of commercial phase and amplitude modulators. The results of the experiment show independent data directed into two different spatial beams simultaneously, using the same RF carrier.