Robust Packaged Fiber-Microcavity Device with over One Billion Q-factor

Whispering gallery mode (WGM) microcavities can confine photons within a microscale volume for long periods of time, strongly enhancing light-matter interactions, and making it a crucial platform in optical science and applications. Current research on microcavity coupling system relays on precise mechanical coupling with microscope monitoring, and its resonance properties are extremely sensitive to external interference, which greatly limits the practical application of microcavities. Therefore, a novel packaged fiber-microcavity device with air/water tightness and stable temperature characteristics is proposed in this paper. A variety of fixatives with different Young's modulus gradients and low coefficients of thermal expansion are used to design a package structure with overall vibration isolation and buffering effect, in order to ensure the stability of the transmission spectrum and improve the robustness of the microcavity module. Through the performance characterization test of the device, it is proved that the packaged microcavities can maintain a quality factor as high as 10^9, and has the advantages of compact size, strong robustness, and versatility. This research work is of great significance to promote the large-scale application of WGMs in high-speed optical communication, nonlinear optics, narrow linewidth lasers, and ultra-high sensitivity sensing.