All-optical image-free microwave photonic down-conversion based on photonic phase shifting and LO frequency doubling

Photonics-assisted image suppression photonic down-converter is an effective way to eliminate image frequency interference in microwave receiver. Due to the performance of the converter largely relies on the local oscillator (LO) signal quality, the frequency converter based on frequency doubling can reduce the demand of the frequency of LO signal. In this paper, we propose and demonstrate an all-optical broadband image-reject photonic down-converter with wideband photonic phase shifting and LO frequency doubling based on a dual-polarization dual-parallel Mach–Zehnder modulator (DP-DPMZM). The experimental results show that the phase shift of I and Q channel can be varied continuously in the range of 360°. And the image rejection ratio of our image-reject photonic down-converter reaches ∼50 dB at the single-tone. For a broadband image signal, the signal-to-noise (SNR) has an improvement of 24 dB. The spurious-free dynamic range (SFDR) value is 102.4 dB⋅Hz2/3.