Excess loss caused by a lossy outer layer in multimode optical fibers

Area of Science:

• Optical Fiber Technology
• Electromagnetic Theory
• Materials Science

Background:

• Multimode step-index fibers are susceptible to excess loss.
• Loss can be introduced by external layers attached to the fiber cladding.
• Understanding this loss is crucial for optical communication systems.

Purpose of the Study:

• To investigate the excess loss in multimode step-index fibers caused by a lossy outer layer.
• To develop theoretical equations for quantifying this excess loss.
• To experimentally validate the theoretical model and analyze wavelength dependence.

Main Methods:

• Utilized electromagnetic theory to derive equations for excess loss based on LP modes.
• Conducted experiments on fibers with a pure fused silica jacket around the cladding.
• Measured excess loss across different wavelengths to determine its dependence.

Main Results:

• Derived theoretical equations for calculating excess loss in the specified fiber configuration.
• Experimental results showed a clear increase in excess loss with increasing wavelength.
• Measured excess loss values closely matched the predictions from the derived theoretical equations.

Conclusions:

• The presence of a lossy outer layer significantly impacts fiber loss.
• Excess loss in such configurations is strongly dependent on wavelength, increasing at longer wavelengths.
• The theoretical model accurately predicts the observed experimental behavior, validating its utility.