Reconfigurable Photonic Microwave Mixer With Mixing Spurs Suppressed and Dispersion Immune for Radio-Over-Fiber System

In this article, a reconfigurable mixer based on only one dual-polarization quadrature phase shift -keying modulator (DP-QPSKM) is proposed and comprehensively demonstrated for a radio-over-fiber (RoF) system. By changing the detection unit and adjusting the dc voltages, the single-ended, double-balanced, image (IM)-free, mixing spurs suppressed, and dispersion-immune mixing can be implemented. Experimental results show that the ~60-dB IM rejection ratio and the spur suppression ratio are achieved. Moreover, the dispersion-induced power fading is successfully compensated by the dc voltage adjustment. The spurious-free dynamic range (SFDR) is about 100.56 dB.Hz
^2/3
. Only one optical path is required without extra optical filters or phase-related devices, which makes the structure concise and stable. This structure would be more compact to meet the potential of integration if a dispersion medium with smaller size is available.