A Broadband Microwave Photonic Mixer with the Capability of Phase Shifting

A broadband microwave photonic mixer with 360-degree phase tunable range and without optical filter is proposed. In the proposed system, two integrated dual-parallel Mach-Zehnder modulators (DPMZM) and a phase modulator (PM) are used. The two DPMZMs driven by the local oscillator (LO) and the radio frequency (RF) signals respectively are properly biased at the minimum transmission point to serve as a carrier-suppressed single-sideband (CS-SSB) modulators. Beating between the two sidebands at a photodetector generates a/an RF/IF signal with a phase equal to the optical phase difference controlled by the bias voltage of PM. The proposed system is theoretically verified and demonstrated, the results that a RF signal from 15 to 39 GHz and an IF signal from 5 to 29 GHz, and a full 360° continuous phase shift of the output IF/RF signal are achieved.