Filter-free microwave photonic single-sideband mixer with mixing spurs suppressed based on dual-polarization dual-drive Mach–Zehnder modulator

A filter-free microwave photonic single-sideband mixer based on dual-polarization dual-drive Mach–Zehnder modulator (DPol-DDMZM) is proposed and verified experimentally. By adjusting the bias voltages of two DDMZMs, each DDMZM generates a single-sideband (SSB) signal with upper or lower sideband. The optical carrier is cancelled by adjusting the polarization controller before a polarizer. The single-sideband frequency upconversion and downconversion are independently achieved with the mixing spurs suppressed. The proposed frequency converter has a large operating bandwidth since no filter is used, and there is no dispersion-induced power fading due to the SSB modulation when transmitting in a long fiber with a dispersion. Experimental results show that all the mixing spurs are well suppressed over a wideband frequency range, and the maximum sideband suppression ratio of desired signal is up to 36 dB.