A system comprises an optical processor comprising a sideband generator, an optical filter, and a phase-shift-keying (PSK) modulator, wherein: the sideband generator generates optical frequency sidebands about a carrier frequency of an optical signal; the optical filter discriminates between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be used to generate an optical millimeter-wave signal; the PSK modulator comprises an optical splitter, an optical phase delay unit, two or more optical gates, and an optical combiner; the optical splitter divides the optical millimeter-wave signal into two or more intermediate signals; the optical phase delay unit delays one or more of the intermediate signals to create distinct phase relationship between them; the optical gates modulate each intermediate signal individually, based on a control input; and the optical combiner combines the gated intermediate signals into a single, PSK-modulated optical millimeter-wave signal.