High-accuracy measurement of cladding noncircularity based on phase velocity difference between acoustic polarization...

Area of Science:

• Materials Science
• Optical Engineering
• Acoustics

Background:

• Accurate measurement of fiber noncircularity is crucial for optical performance.
• Existing methods may lack precision for very low ellipticity values.
• Silica glass fibers are fundamental components in telecommunications and sensing.

Purpose of the Study:

• To develop and demonstrate a high-accuracy measurement method for silica glass fiber noncircularity (ellipticity).
• To establish a quantitative relationship between acoustic wave properties and fiber ellipticity.
• To validate the method across different types of optical fibers.

Main Methods:

• Utilizing the phase velocity difference between two eigen polarization modes of the lowest-order acoustic flexural wave.
• Formulating the mathematical relationship connecting acoustic phase velocity difference to fiber ellipticity.
• Experimentally testing the method on photonic crystal fiber, elliptical core fiber, and standard single-mode fiber.

Main Results:

• Successfully demonstrated a high-accuracy measurement of fiber ellipticity.
• Achieved precise measurements for ellipticity values below 0.001.
• Validated the method's applicability to diverse optical fiber structures.

Conclusions:

• The acoustic flexural wave method provides a highly accurate means to measure silica glass fiber ellipticity.
• This technique is effective for characterizing even minute deviations from circularity in optical fibers.
• The findings contribute to improved quality control and performance prediction in fiber optics.