Photonic generation of multi-frequency dual-chirp microwave waveform with multiplying bandwidth

Abstract

Abstract A photonic approach to generate dual-chirp microwave waveform with multi-carrier frequencies and multiplying bandwidth is proposed and demonstrated by using a dual-polarization Mach-Zehnder modulator (DPol-MZM) and balanced detection. In the approach, the DPol-MZM driven by a baseband waveform modulates the injected optical signal to generate optical broad-spectra sidebands. After heterodyne in balanced photodetector (BPD), multi-frequency dual-chirp microwave waveform can be generated. The proposed generator allows the injected optical signal with arbitrary intensity modulation format. The key features of the approach are the multi-carrier frequencies generation ability and the bandwidth multiplying operation. The proposed approach is verified by simulation. Dual-chirp signal with four-carrier frequencies is generated by employing optical frequency comb (OFC) with five comb lines. Auto-correlations of the generated signals show good pulse compression ratio and high peak-to-sidelobe ratio. The maximum frequency number of the system is analyzed, and the maximum power ratio is also investigated.