Аннотация:A new type of narrow-band optical filters based on spherical microresonators with the ``whispering gallery''-type modes is proposed. Realized is the relative bandwidth of the whispering-gallery modes from $1\times10^{-6}$ to $1\times10^{-9}$ at $\lambda=0.63\mu m$ and to $1\times10^{-8}$ at $\lambda=1.15\mu m$ with fused quartz microresonators. The 0.1% tuning of mode frequencies in glass microresonators with the relative mode bandwidth to $5\times10^{-8}$ at $\lambda=0.63\mu m$ is demonstrated. The analysis of characteristics of a prism-type coupler for the high-Q whispering-gallery modes is presented; the conditions for realization of the 100% coupling to optimal Gauss-Hermitian beams are formulated.