| 摘要 |
In accordance with one aspect of my invention, the core and cladding regions of a hollow-core optical fiber are configured so that a signal mode is coupled to a cladding mode in order to exploit polarization-dependent properties. In general, the fiber comprises a hollow-core region surrounded by a cladding region, which includes a localized hollow-waveguide region. The core and waveguide regions are configured so that the coupling between a signal mode in the core region and a cladding mode in the waveguide region are phase-matched for efficient coupling, and the phase-matching condition is made polarization-dependent to provide improved control of the fiber's polarization dependent properties. In a preferred embodiment, the cladding region comprises a bandgap structure. In one embodiment, the at least one region has a non-symmetric cross-sectional shape (e.g., oblong) with respect to one of its transverse axes. In an alternative embodiment, both the core region and the waveguide region are non-symmetric but with respect to orthogonal axes. In another embodiment, the at least one region has a multiplicity of micro-defects disposed at or near the periphery thereof and in a non-rotationally-symmetric pattern. In an alternative embodiment, both the core region and the waveguide region include a multiplicity of micro-defects at or near the periphery thereof in a non-rotationally-symmetric pattern. Optical fibers of this type find application in polarization-dependent optical couplers (e.g., splitters, polarizers) and in sensors.
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