Brillouin lasing in a hybrid silicon chip

Low phase noise lasers are used throughout many applications including precision metrology [1], and pure microwave synthesis [2], among others. Stimulated Brillouin scattering (SBS), a coherent interaction between photons and phonons, is capable of spectrally purifying optical sources to sub-Hz levels [3]. Previous demonstrations of Brillouin lasers have been limited to fiber based systems or micro-resonators which use tapered fibers or prisms to couple to external setups, preventing wafer scale integration and mass production.