Specialty Optical Fibers Handbook

to the 1/R scaling that one expects in the absence of zero-field boundary condi-

tions.

In fact, similar 1=R

3

scaling occurs for any other loss phenomenon associated

with the penetration of the field into the cladding, including radiation loss and

surface-roughness scattering, for exactly the same reasons.

10.2.3.3 Loss Discrimination and Single-Mode Behav ior

A waveguide with a large hollow core, whether metallic or dielectric, is

intrinsically multimode. However, in practice the observed behavior is typically

that all of the power is guided in one or a few modes. The reason for this can be

seen in the absorption loss spectra of Fig. 10.14: different ...