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240 Hz linewidth Brillouin laser from a microrod whispering gallery mode resonator



William Loh, Aurelien C. Coillet, Frederick N. Baynes, Scott B. Papp, Scott A. Diddams, Joe Becker


We demonstrate an ultra-low noise laser that oscillates based on the stimulated Brillouin scattering nonlinearity in an optical microresonator. Our Brillouin laser employs a microrod resonator whose larger mode volume compared to conventional resonators increases the system’s thermal time constant by two orders of magnitude to the level of 9.4 ms (or 17 Hz). The longer thermal response results in an averaging of the thermal fluctuations, which is the dominant source of noise at low frequencies common to all microresonator devices. We investigate the steady-state performance of this laser and analyze its operation state through measurements of the laser’s mode detuning and lineshape. We also characterize its noise performance in terms of fluctuations in both frequency and amplitude and show that laser linewidths on the order of 235 Hz can be realized from a microcavity device 6 mm in diameter. Our results indicate a fundamental mechanism for noise that is common to all microresonator devices and due to the inherent coupling between intracavity power and mode frequency.
New Journal of Physics


Nonlinear Optics, Microresonators, Optoelectronics


Loh, W. , Coillet, A. , Baynes, F. , Papp, S. , Diddams, S. and Becker, J. (2015), 240 Hz linewidth Brillouin laser from a microrod whispering gallery mode resonator, New Journal of Physics, [online], (Accessed June 13, 2024)


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Created September 29, 2015, Updated November 10, 2018