Brillouin backaction thermometry for modal temperature control

Stimulated Brillouin scattering provides optical gain for efficient and narrow-linewidth lasers in high-Q microresonator systems. However, the thermal dependence of the Brillouin process as well as the microresonator frequencies impose strict temperature control requirements for long term frequency-stable operation. Here, we study Brillouin backaction and use it to both measure and phase-sensitively lock modal temperature to a reference temperature defined by the Brillouin phase matching condition. At a specific lasing wavelength, the reference temperature can be precisely set by adjusting the resonator's free spectral range. This backaction control method is demonstrated in a chip-based Brillouin laser, but can be applied in all Brillouin laser platforms. It offers a new approach for frequency-stable operation of Brillouin lasers in atomic clock, frequency metrology, and gyroscope applications. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Stimulated Brillouin scattering provides optical gain for efficient and narrow-linewidth lasers, but strict temperature control is required for long term frequency-stable operation. This study explores Brillouin backaction for measuring and phase-sensitively locking modal temperature to a reference temperature, offering a new approach for frequency-stable operation of Brillouin lasers.