Photonic Image-free Mixer Based on a Dual-Parallel Mach-Zehnder Modulator and Fiber Dispersion for Radio-Over-Fiber System

In this paper, a simple image rejection mixer based on the dispersion effect in the single mode fiber is proposed and experimentally demonstrated for the radio-over-fiber (RoF) system. The key idea is to control the DC bias voltages of the dual parallel Mach-Zehnder modulator (DPMZM) to compensate for the desired components and eliminate the image induced components simultaneously during the fiber transmission. The experimental results show, the image rejection ratio (IRR) of 50 dB is realized, and the spurious free dynamic range (SFDR) is about 100.75 dBHz23. In addition, the results also demonstrate an image-free intermediate frequency (IF) range of 0.5GHz9.5GHz. This image-free mixer can be widely employed in the radio-over-fiber (RoF) system, and greatly simplify the receiver structure in the base station.