Reconfigurable microwave photonic mixer with minimized path separation and large suppression of mixing spurs

A compact reconfigurable photonic microwave mixer is proposed and demonstrated based on a dual-polarization Mach-Zehnder modulator and an optical 90-deg hybrid. By simply changing the photodetection schemes, single-ended, double-balanced, I/Q, and image-reject mixing can be implemented. Thanks to the sidebands selection by an optical filter, unwanted mixing spurs are highly suppressed. In addition, the system is insensitive to environmental vibration because the optical path separation is minimized. An experiment is carried out. Reconfigurable mixing functionalities with very small phase dithering are verified. The mixing spurs are suppressed by more than 30 dB, and the image-reject ratio for image-reject mixing is about 40 dB.