Analysis of half-tapered fiber coupling for microresonators

Abstract

Although evanescent fields from tapered optical fibers with small diameters (<5 μm) enable efficient coupling to microresonators, fabrication and handling difficulties motivate the use of half-tapered fibers. As a prelude to microresonator coupling, however, we quantify just the coupling between two half-tapered fibers using fabrication, theory, design analysis, simulation and experimental verification. The dependence of coupling strength on taper diameter, fiber separation and coupling length are highlighted.