Tunable Fourier Domain Mode-Locked Optoelectronic Oscillator Using Stimulated Brillouin Scattering

We propose and demonstrate a tunable Fourier domain mode-locked optoelectronic oscillator (OEO) using a frequency scanning microwave photonics filter (MPF) based on stimulated Brillouin scattering (SBS). Fourier domain mode locking operation is achieved by synchronizing the tuning period of the SBS-based MPF to the cavity round-trip time of OEO. As a result, thousands of longitudinal modes are stimulated simultaneously in the OEO cavity. Linearly chirped microwave waveforms with a chirp rate up to 0.84 GHz/μs and a time bandwidth product as high as 22446 are generated in the experiment. The proposed approach provides an important solution for chirped microwave waveforms generation, which is widely used in modern radar and communication systems, and has the potential to be integrated on a chip.