Brillouin integrated photonics: advances in heterogeneous integration, surface acoustic waves, and post-fabrication tuning

Brillouin integrated photonics has emerged as a powerful platform for enabling advanced signal processing, sensing, and light generation on-chip. This talk will review recent breakthroughs in heterogeneous integration, allowing Brillouin-active photonic circuits to incorporate electro-optic functionalities such as modulators and photodetectors. These advances pave the way for compact and efficient photonic processors that harness both optical and acoustic interactions in novel ways. Additionally, I will highlight the recent demonstration of surface acoustic wave (SAW) excitation in integrated photonic waveguides, a development that unlocks new sensing capabilities by leveraging the waveguide surface. This also enables strong Brillouin interactions in materials traditionally lacking acoustic guidance, as well as SAW excitation in non-piezoelectric materials—expanding the material design space for next-generation Brillouin devices. Finally, I will discuss recent work on post-fabrication grating inscription in chalcogenide microresonators, which allows for the controlled inhibition of Brillouin lasing through an induced bandgap.