Transmission characteristics of a coaxial optical fiber line

A coaxial optical fiber line is proposed and studied as a long-distance transmission medium. The radial structure consists of a core surrounded by two clads. The inner clad has higher refractive index than the core and the outer clad. Guided modes are thus characterized by a concentrated field in the inner clad and evanescent fields in both the core and the outer clad. Using a rigorous modal analysis, characteristic curves for a monomode coaxial fiber line are presented. It is shown that the zero-dispersion wavelength can be placed at any desired value by proper choice of the refractive index contrast and the fiber dimensions. The proposed coaxial line compares well with the known W-profiled line with respect to ease of manufacture and dispersion characteristics.<
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