Fluorescence profiling of single-mode optical fiber preforms.

Area of Science:

• Optoelectronics and Photonics
• Materials Science and Engineering

Background:

• Accurate measurement of refractive-index profiles is crucial for single-mode optical fiber performance.
• Existing methods like interferometry and the focusing method can be time-consuming or require index matching.

Purpose of the Study:

• To present a novel, rapid, nondestructive, and noncontacting method for measuring the refractive-index profile of optical fiber preforms.
• To demonstrate the efficacy of UV-induced fluorescence for direct index profile mapping.

Main Methods:

• Utilizing the strong fluorescence of Ge-doped preform cores when excited by UV radiation (325 nm He-Cd laser).
• Employing a video camera to detect fluorescence intensity and generate the index distribution.
• Exciting the preform transversely to its axis, eliminating the need for index matching.

Main Results:

• The developed method provides accurate refractive-index profiles of optical fiber preforms.
• Profiles are obtained in under one minute.
• Results show excellent agreement with established techniques such as interferometry and the focusing method.

Conclusions:

• The fluorescence-based method is a simple, fast, and accurate alternative for optical fiber preform characterization.
• This technique simplifies the measurement process, making it more accessible.
• It offers a powerful new tool for optical fiber manufacturing and research.