Photonic generation of millimeter-wave-band 16-QAM and 16-ASK signals based on orthogonal polarization multiplexing

Two novel schemes are proposed to generate 16-ary square quadrature amplitude modulation (16-QAM) signal and 16-ary amplitude shift keying (16-ASK) at millimeter-wave (mm- wave) band. The proposed schemes principally consist of three Mach-Zehnder modulators (MZMs) and a polarization splitter (PBS). The detailed theoretical analysis and simulation results are given out. Compared with the conventional methods, the electronic circuits are simplified in our proposed schemes by employing photonic vector modulator (PVM) in which only one single-wavelength laser and one high speed MZM are needed.