W-Band PDM-QPSK Vector Signal Generation by MZM-Based Photonic Frequency Octupling and Precoding

We experimentally demonstrate polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) modulated vector signal generation at the W-band, adopting Mach-Zehnder-modulator-based (MZM-based) photonic frequency octupling and phase precoding techniques. The MZM biased at its maximum transmission point is driven by a 12-GHz precoded vector signal, which is generated by MATLAB programming and carries up to 4-GBd QPSK transmitter data. The phase of the 12-GHz precoded vector signal is one eighth that of the regular QPSK symbol to overcome the phase octupling effect accompanying the frequency octupling during square-law photodiode (PD) detection. Only one polarization beam splitter is needed to implement optical polarization diversity. The generated 96-GHz vector signal can carry up to 4-GBd PDM-QPSK data. To the best of our knowledge, this is the first time that the generation and reception of the polarization multiplexing vector signal has been recognized by one external intensity modulator at the W-band.