Integrated Brillouin lasers and their applications

In this chapter we give a brief history of the Brillouin gain process in optical waveguides and SBLs realized with integrated Brillouin resonators. A brief discussion on the laser fundamental and integral linewidths, the fractional frequency noise, and drift is provided. We discuss progress to date on Brillouin processes in integrated silica, silicon nitride, silicon, and chalcogenide platforms. The underlying Brillouin physics in waveguide materials and the range of waveguide structures and related requirements for photon–phonon phase matching are covered as well as research efforts to implement SBS gain and lasing in these waveguide material systems. Cascaded Brillouin lasing is discussed, including mode engineering approaches to inhibit cascading to enable further linewidth narrowing and higher output powers. Finally, several applications using these integrated Brillouin technologies are presented.