Simplified dual-output and filter-free photonic-assisted single sideband mixer using a 2 × 2 optical coupler

A simplified dual-output and filter-free photonic-assisted single sideband mixer is proposed, which uses a 2×2 optical coupler (OC) instead of a 2×4 optical hybrid to process optical modulation signals. Using two dual-parallel Mach–Zehnder modulators (DPMZMs) in parallel to achieve carrier-suppressed single-sideband modulation of the radio frequency (RF) signal and carrier-suppressed double-sideband (CS-DSB) modulation of the local oscillator (LO) signal at DPMZM1 and CS-DSB modulation of the LO signal only at DPMZM2, with a 2×2 OC coupling, the down- and up-converted RF signals can be obtained simultaneously and output separately. Because the −1st-order or +1st-order optical sidebands of the LO signal can be canceled out via a 2×2 OC instead of a 2×4 optical hybrid or an optical filter in previous reports, the proposed mixer has a simplified structure and a large bandwidth. Simulation results show that the proposed mixer has mixing spurs suppression of over 30 dB, frequency tunability, and spurious-free dynamic range of over 101.55 dB·Hz2/3. In addition, to evaluate the mixer performance for the broadband signal, 16-quadrature amplitude modulation RF vector signals with tunable center frequency are applied to the mixer, and the measured error vector magnitudes of the down- and up-converted vector signals are <1.53%.