Highly birefringent lamellar core fiber.

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Polarization-maintaining fibers (PMFs) are crucial for optical communication and sensing.
• Existing PMFs often rely on stress-induced birefringence, which can be challenging to control.
• Artificial anisotropy offers an alternative approach to birefringence control in optical fibers.

Purpose of the Study:

• To report the development and characterization of a novel polarization-maintaining fiber.
• To investigate the impact of core material anisotropy on fiber birefringence.
• To model the fiber's performance, considering diffusion effects between core layers.

Main Methods:

• Fabrication of a polarization-maintaining fiber with artificially introduced core anisotropy.
• Measurement of beat length using direct observation at multiple wavelengths (e.g., 543 nm).
• Analysis of phase-index birefringence and differential group delay, incorporating diffusion modeling.

Main Results:

• Achieved a shortest beat length of 85 micrometers at 543 nm.
• Measured phase-index birefringence was approximately one-third of the theoretically expected value.
• Diffusion between thin core layers (<200 nm) was identified as the cause for reduced birefringence.

Conclusions:

• The developed fiber demonstrates effective polarization maintenance through artificial core anisotropy.
• Accounting for inter-layer diffusion is essential for accurate modeling of fiber performance.
• The model accurately predicts experimental beat length and differential group delay over a broad wavelength range.