Photonic generation of binary and quaternary phase-coded microwave waveforms with an ultra-wide frequency tunable range

A novel photonic approach to generating binary and quaternary phase-coded microwave waveforms with an ultra-wide frequency tunable range is proposed and experimentally demonstrated. In the proposed system, a dual-parallel Mach-Zehnder modulator (DP-MZM) is used as an optical wavelength shifter. To generate a phase-coded microwave waveform, the coding signal is modulated on the original wavelength using a phase modulator (PM). Combining the shifted wavelength and the original wavelength, two wavelengths with a frequency space determined by the input microwave signal are obtained. Applying them to a photodetector (PD), a phase-coded microwave waveform is generated. The key significance of the approach is that both binary and quaternary phase-coded microwave waveforms can be generated with an ultra-wide frequency tunable range. An experiment is performed. The generation of binary and quaternary microwave waveforms with a microwave carrier frequency at 10 and 20 GHz is demonstrated.