Polymer based planar coupling of self-assembled bottle microresonators

摘要

The investigation of a simple and self-assembling method for realizing polymeric micro-bottle resonators is reported. By dispensing precise amounts of SU-8 onto a cleaved optical fiber, employed as mechanical support, bottle microcavities with different shapes and diameters are fabricated. The balancing of surface energy between glass fiber and polymeric microresonator with surface tension of SU-8 confers different shape to these microstructures. Planar single-mode SU-8 based waveguide, realized on polymethylmethacrylate, is chosen for exciting the micro-bottle resonators by evanescent wave. The reliability of the fabrication process and the shape of the bottle microcavities are investigated through optical analysis. We observe whispering gallery modes in these resonant microstructures by a robust coupling with single mode planar waveguides around 1.5 μm wavelength. The resonance spectra of micro-bottle resonators and the spectral characteristics, such as Quality-factor (Q factor) and free spectral range, are evaluated for all the realized microstructures. SU-8 micro-bottle resonators show high Q-factors up to 3.8 × 10~4 and present a good mechanical stability. These features make these microcavities attractive for sensing and/or lasing applications in a planar platform.