Numerical Simulation of Influence of the Thermal and Mechanical Fluctuations in the Coupling Elements of Microresonators

• Published in: 2021 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS) pp. 1 - 4
• Main Authors: Pavlov, Vladislav I., Blinov, Igor Yu, Khatyrev, Nickolay P., Kondratiev, Nikita M., Bilenko, Igor A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 07.07.2021
• Subjects: Laser noise; Laser stability; laser stabilization; Masers; Measurement by laser beam; Microcavities; microresonator; Microwave measurement; Optical variables measurement; self-injection locking; thermorefraction
• ISSN: 2327-1949
• DOI: 10.1109/EFTF/IFCS52194.2021.9604269

Ultra-stable lasers of high spectral purity are the technological basis for optical atomic clocks, quantum measurements, stable microwave signal sources and high-resolution optical spectroscopy. For these purposes, lasers with a linewidth of the order of hertz are used. Such lasers are usually stabilized with Fabry-Perot resonators made of ultra-low expansion materials, which are very fragile and bulky. Therefore, there is a clear demand for reliable miniature lasers with narrow linewidths. Optical resonators with a "whispering gallery" mode (WGM) make it possible to create narrow-band microlasers on their basis using self-injection locking method. But they have not yet reached the stability determined by their fundamental noise. Here we calculate the noise characteristics of lasers self-injection locked to WGM microresonators and estimate the linewidth limitations due to thermorefractive, thermoelastic, photoelastic and Brownian noise. We also calculated the total noise in an integrated waveguide and obtained an estimate of the linewidth of 0.5 kHz at an averaging time of 1 s.