Switchable down-, up- and dual-chirped microwave waveform generation with improved time–bandwidth product based on polarization modulation and phase encoding

A switchable down-, up- and dual-chirped microwave waveform generation technique with improved time–bandwidth product (TBWP) is proposed and demonstrated based on a dual-polarization dual-parallel Mach–Zehnder modulator (DP-DPMZM) cascaded with a polarization modulator (PolM). By properly controlling the phase shifts of the radio frequency signals applied to the DP-DPMZM, switchable down-, up- and dual-chirped waveforms with simultaneous frequency and bandwidth doubling can be generated. To enlarge the TBWP further, splitting parabolic signal and phase-encoding splitting parabolic signal are used to drive the PolM for the enhancement of bandwidth and time duration. Numerical results demonstrate the generation of down-, up- and dual-chirped microwave waveform with TBWP of 8, 160 and 10240. The proposed method may find applications in future multifunction radar systems due to the high performance and flexibility.