Photonic generation of dual-band dual-chirp microwave signal with quadrupled frequency based on sideband-selective modulation

Abstract

A photonic architecture for generating dual-band dual-chirp microwave waveforms is proposed and demonstrated, leveraging non-reciprocity in a Sagnac loop configuration for sideband-selective modulation. In the first stage, two parallel dual-parallel Mach-Zehnder modulators (DP-MZMs), driven by independent RF signals, produce optical sidebands that are subsequently separated and polarized orthogonally. The optical signal processed in the first stage is injected into the Sagnac loop, where it undergoes selective secondary modulation via an embedded dual-electrode Mach-Zehnder modulator (MZM). Finally, the multiplexed output is subjected to polarization conditioning and detected by a balanced photodetector (BPD), generating a dual-band dual-chirp microwave waveform centered at 32 GHz and 50 GHz (quadruple the frequency of the driven signal) with a bandwidth of 4 GHz and a 1 μs duration. Moreover, the proposed architecture offers reconfigurability, facilitating the generation of not only dual-band dual-chirp signals but also single-band dual-chirp and quad-band chirp signals through flexible parameter tuning.