Leaky modes in graded index optical fibers

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Graded index optical fibers are crucial for modern telecommunications.
• Understanding attenuation mechanisms is vital for fiber performance optimization.

Purpose of the Study:

• To derive leaky mode attenuation coefficients for graded index optical fibers.
• To investigate the contribution of leaky modes to fiber measurements.
• To identify potential discrepancies in current optical fiber loss models.

Main Methods:

• Utilized the Wentzel-Kramers-Brillouin (WKB) approximation for mathematical derivation.
• Explicitly evaluated attenuation coefficients for a parabolic index profile.
• Calculated the leaky mode contribution to near field and attenuation measurements.

Main Results:

• Derived leaky mode attenuation coefficients for graded index optical fibers.
• Quantified the impact of leaky modes on near field and attenuation measurements.
• Observed a lack of expected leaky mode contributions in several tested graded index fibers.

Conclusions:

• The WKB approximation provides a framework for calculating leaky mode attenuation.
• Experimental results deviate from theoretical predictions for leaky modes in some graded index fibers.
• An unidentified additional loss mechanism may be present in these optical fibers, impacting signal integrity.