Microwave photonic mixer with large mixing spurs suppression and high RF/LO isolation

A microwave photonic single sideband mixer based on a dual-polarization dual-parallel Mach-Zehnder modulator (DP-DPMZM) modulator is proposed. A radio frequency (RF) signal and a local oscillator (LO) signal were loaded to the modulator through two electrical 90° hybrid couplers, respectively. The carrier-suppressed single sideband (CS-SSB) modulation was achieved by setting the six DC biases of the DP-DPMZM modulator. Experimental results demonstrate that the proposed mixer for both the upconversion and downconversion has high purity with a large suppression ratio of the undesired signals (∼30 dB). Since the RF and LO signals respectively drive the DP-DPMZM modulator through two electrical 90° hybrid couplers, the proposed link has good RF/LO isolation that reaches 49.1 dB. The proposed microwave photonic mixer provides an alternative with high purity and isolation for the transmitter, receiver and phased array beamforming in microwave photonic applications.