Progress in the Surface Nanoscale Axial Photonics (SNAP)

Surface Nanoscale Axial Photonics (SNAP) is a recently introduced platform for fabrication of complex miniature photonics circuits and devices by nanoscale variation of the optical fiber radius. It is shown that such dramatically small deformation of the optical fiber (and/or equivalent variation of refractive index) is sufficient to localize the whispering gallery modes propagating along the fiber surface normal to its axis and to create high Q-factor microresonators. Reproducible fabrication of these microresonators with angstrom accuracy supports the robustness of the SNAP platform. Series of identical high Q-factor SNAP microresonators coupled to each other are demonstrated. Due to the significantly smaller surface roughness of drawn silica compared to the roughness of surfaces fabricated lithographically, it is expected that the SNAP circuits will enable orders of magnitude smaller attenuation of light compared to the planar ring microresonator and photonic crystal microcavity circuits.