Fabrication of coaxial dual-waveguide structured optical fiber with an annular waveguide layer

Abstract

A coaxial dual-waveguide structured optical fiber with an annular waveguide layer (CDOF) is designed and its preparation method is provided thereof. The responding preform is fabricated by MCVD technique and then is drawn by a custom-made fiber drawing tower. The optical fiber has a common fiber core and an annular waveguide layer on the outer surface of the optical fiber. The refractive index profile is measured by a refracted near-field technique and a standard cutback technique. The fiber can be applied in a novel optical fiber device or an optical fiber sensor, for example, in-fiber integrated Michelson or Mach-Zehnder interferometer.