Optical fiber profiles using the refracted near-field technique: a comparison with other methods

Area of Science:

• Optical Engineering
• Materials Science

Background:

• Accurate characterization of multimode fiber refractive index profiles is crucial for optical communication systems.
• Existing methods like interferometric techniques are highly accurate but can be complex.

Purpose of the Study:

• To validate the accuracy of the refracted near-field (RNF) method for multimode fiber profiling.
• To introduce a rapid calibration technique for the RNF method.
• To assess the impact of external factors on RNF measurements.

Main Methods:

• Comparison of multimode fiber profiles obtained by the RNF method and the interferometric slab technique.
• Analysis of differences in Delta and alpha parameters between RNF and transverse interferometric methods.
• Development and application of a liquid temperature-based calibration method for RNF.

Main Results:

• RNF profiles agree within +/-0.5% with interferometric profiles in regions of adequate resolution.
• Average differences in Delta and alpha between RNF and interferometric methods are 4% and 3%, respectively.
• The RNF technique achieves a refractive index determination precision of 4 x 10(-5).

Conclusions:

• The refracted near-field method is a highly accurate and precise technique for characterizing multimode fiber profiles.
• The presented rapid calibration method enhances the practicality of RNF measurements.
• Understanding the effect of foreign matter is important for reliable RNF analysis.