Abstract: A tunable, all-optical, coupling method for a high-Q silica microsphere and an optical waveguide is disclosed. By means of a novel optical nanopositioning method, induced thermal expansion of an asymmetric microsphere stem for laser powers up to 211 mW is observed and used to fine tune the microsphere-waveguide coupling. Microcavity displacements ranging from (0.61±0.13)-(3.49±0.13) ?m and nanometer scale sensitivities varying from (2.81±0.08)-(17.08±0.76) nm/mW are obtained. Additionally, an apparent linear dependency of coupling distance on stem laser heating is achieved. Using these methods, coupling can be altered such that the differing and customizable coupling regimes can be achieved.

Abstract: A tunable, all-optical, coupling method for a high-Q silica microsphere and an optical waveguide is disclosed. By means of a novel optical nanopositioning method, induced thermal expansion of an asymmetric microsphere stem for laser powers up to 211 mW is observed and used to fine tune the microsphere-waveguide coupling. Microcavity displacements ranging from (0.61±0.13)?(3.49±0.13) ?m and nanometer scale sensitivities varying from (2.81±0.08)?(17.08±0.76) nm/mW are obtained. Additionally, an apparent linear dependency of coupling distance on stem laser heating is achieved. Using these methods, coupling can be altered such that the differing and customizable coupling regimes can be achieved.