Multichannel Microwave Photonic Phase Shifter With Improved Power Efficiency and Suppressed Third-Order Intermodulation Distortions

Benefiting from the advantages of photonic technologies, the microwave photonic phase shifter (MPPS) has become a key technical enabler for broadband and high-frequency signal processing. However, in all previously reported MPPS schemes, the spurious free dynamic ranges (SFDR) of the systems are all limited, which results from the inherent nonlinear of the electro-optic modulator. Here, our objective is to propose a novel MPPS structure, where the nonlinear distortions can be effectively suppressed via multi-order optical sidebands vector manipulation (MOSVM). In parallel, the power efficiency of the system can also obtain obvious improvement at the same received optical power of the photodetector (PD), thus achieving an MPPS with a significantly enhanced SFDR. Besides, this structure can be easily expanded to form a multichannel MPPS by the means of wavelength-division multiplexing techniques. In the experiments, we investigated the proposed MPPS by utilizing the two-tone signal test, the sweep frequency signal test, the wideband signal transmission test, and the scalability capability test. The measured results indicate that the SFDR of the proposed MPPS system can obtain over 20-dB improvement, and the wideband signal transmission and the OAM beam based on the MPPS achieve better performances. As such, a large-SFDR MPPS is first proposed and experimentally demonstrated in this paper.