Mode attenuation in multimode three-layer fiber waveguides

A theoretical analysis is made of the mode attenuation in a multimode three-layer fiber waveguide consisting of a core and two (intermediate and outer) claddings, the outer cladding being made of a polymer material. It is shown that losses can be reduced to a value close to that characteristic of the core material if the core diameter and aperture are increased and the wavelength is reduced.