Large Bandwidth Photonic Microwave Image Rejection Mixer With High Conversion Efficiency

A photonic microwave image rejection mixer (IRM) with large operating frequency range and high conversion efficiency is presented in this paper. The scheme is achieved by using a photonic microwave phase shifter, which is based on a polarization-division multiplexing Mach-Zehnder modulator (PDM-MZM). Thanks to the large operating frequency range of the photonic microwave phase shifter, the operating frequency of the proposed IRM can extend to 40 GHz. Besides, the system has high conversion efficiency, owing to the suppression of the optical carrier and application of balanced photodetector. To verify the scheme, an experiment is performed. Experimental results demonstrated large operating frequency range (5-40 GHz) and high image rejection ratio (40 dB) of the mixer. Compared with the conventional photonic microwave mixer, a 19-dB improvement of conversion efficiency is realized in the experiment.