Photonic generation of frequency 12-tupling millimeter-wave based on three cascaded-MZMs and polarization multiplexing

Optical millimeter-wave generation is a predominant approach for the generation of high-quality carrier signals for future wireless transmissions. This paper proposes an optical frequency 12-tupling millimeter-wave generation scheme using three cascaded-MZMs assisted by polarization multiplexing for carrier suppression. A three-stage MZM architecture produces the desired sixth-order sidebands along with the undesired carrier signal. The proper adjustment of polarization direction and angle of polarization rotation lead to the effective suppression of the undesired optical carrier signal. A comprehensive mathematical analysis has been accomplished to evaluate the system's performance, and the obtained results are also validated through simulation findings. The derived results demonstrate that the proposed system is capable of operating over a broad modulation index range extending from 1.5 to 4.5, thereby relaxing the stringent requirements for a constant modulation index. The proposed system generates high-purity mm-wave signals with an OSSR of 62.06 dB and an RFSSR of 54.79 dB at a modulation index of 2.6. Moreover, it is also validated that even if the system parameters like modulation index, polarizer rotation angle, and phase difference among RF driving signals deviate from their ideal values to a certain degree, the system performance remains acceptable. The involvement of polarization technique, omission of wavelength-dependent devices, and a large modulation index operating range make this methodology readily appealing for implementation in radio-over-fiber transmissions.