A novel method to realize optical single sideband modulation with tunable optical carrier to sideband ratio

An optical single sideband (OSSB) modulation method with tunable optical carrier to sideband ratio (OCSR) is proposed and experimentally demonstrated based on a dual-polarization Mach–Zehnder modulator (DPol-MZM). An orthogonally polarized double sideband (DSB) signal output from the DPol-MZM is filtered out the carrier and one sideband utilizing an optical bandpass filter (OBPF). Then the orthogonally polarized OSSB signal is transformed into a linear polarized OSSB signal by a polarizer (Pol). By changing the polarization direction of the Pol utilizing a polarization controller (PC), the tunable OCSR can be achieved. In the demonstrated experiments, an OSSB modulation is implemented over the wide microwave frequency range of 5–30 GHz. The OCSR is tuned from −30 dB to infinity. The proposed OSSB modulation method is advantageous in many respects as large tunable OCSR range, wide operation bandwidth, and simple structure.