Studying of filtering properties of SNAP microresonators on the surface of optical fibers

Cylindrical microresonators based on the surface of optical fibers (SNAP structures) appear to be a promising platform for a variety of photonic devices. It turned out that the manufacturing accuracy of standard telecommunication optical fibers and the smoothness of their surface may be high enough to excite high-quality whispering gallery (WGM) modes in their cladding. Here we consider the question of the quality of resonances obtained on the surface of optical fibers, and the possibility of using them to create high-finesse optical filters. We used standard telecommunication fiber SMF-28 with a silica cladding diameter of 125 microns as samples to excite whispering gallery modes. We found that annealing with fire allows to obtain quality factors up to Q similar to 10(7). Corresponding decay time in the microcavity was measured to be tau similar to 15 ns. We also discussed different schemes of optical filters that may be based of cylindrical microresonators.