Thermal Characteristics of Brillouin Microsphere Lasers

In this paper, we investigate the thermal characteristics of Brillouin microsphere lasers. A mathematical model for Brillouin lasing in a waveguide coupled microcavity is constructed based on the coupled mode theory, the analytic correlation between lasing and thermal power is given. To track the thermal responses of Brillouin microlasers, we introduce two kinds of thermal perturbations on the packaged silica microspheres by either tuning the wavelength of pump wave or varying the surrounding temperature. It is shown that the output power of Brillouin lasers is sensitive to and linearly varied with the thermal change of the mode area and surroundings. The optical bistabilities induced by the resonances transitions of the pump wave and Brillouin lasing, and a single mode lasing with up to 41.7-dB side mode suppression ratio are demonstrated. Our results demonstrate that Brillouin microlasers with stable performances hold potential for sensor applications since thermal or optical perturbations on microcavity can be simply tracked by the variation of output power.