Photonic approach to dual-band dual-chirp microwave waveform generation with multiplying central frequency and bandwidth

Abstract A novel photonic approach to generate frequency and bandwidth multiplying dual-chirp microwave for application in dual-band radar system is proposed using an integrated dual-polarization quadrature phase shift keying (DP-QPSK) modulator. The proposed approach is based on optical frequency multiplying and polarization selection. In the approach, the baseband signal and RF signal are injected into the DP-QPSK modulator to generate optical broad spectra and sidebands respectively. By adjusting the bias points of the DP-QPSK modulator, after polarization selection and optical to electrical conversion, frequency-quadrupling bandwidth-octupling and frequency-double bandwidth-quadrupling or frequency-tripling bandwidth-sextupling and frequency-fundamental bandwidth-doubling dual-chirp signals can be generated in the single structure respectively. The proposed approach is verified by simulations. Dual-chirp microwaves with central frequency–bandwidth of 32 GHz-8 GHz, 16 GHz-4 GHz or 24 GHz-6 GHz, 8 GHz-2 GHz are generated in the two ports respectively. Their autocorrelation results manifest good pulse compression capabilities. The central frequency, bandwidth, chirp rate and time duration can be tuned independently. The generated dual-chirp signals show good performance on the range-Doppler coupling and can significantly improve the range-Doppler resolution in dual-band radar system.