Single Sideband Suppressed Carrier Modulator for C-Band Multiple Access FSO Communication

A Design procedure to realize a single sideband suppressed carrier (SSB-SC) modulator for free space optical (FSO) communication is theoretically presented. The operating principle relies on introducing spatiotemporal modulation into an indium-tin-oxide integrated plasmonic metasurface to obtain a time-varying output signal that is characterized by a sawtooth phase profile spanning on 2π and a constant amplitude. It is demonstrated that such spatiotemporal modulator transfers the incident signal into the first-order up-modulated sideband with more than 99% frequency conversion efficiency. The optical carrier suppression and undesired sideband rejection of 44 dB and 39 dB are calculated for the SSB-SC modulator, respectively. The application of the high-performance elements for multichannel multibeam scanning over a space-time shared-aperture platform is investigated. Thanks to the strong suppression of all undesired mixing products, the crosstalk between the channels with the same operating wavelength is significantly reduced.