Multi-trench fiber with four gaps for improved bend performance.

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Standard multi-trench fibers (MTFs) face challenges in achieving robust single-mode operation and bending resistance.
• Fabrication accuracy for MTFs can be a limiting factor in their practical application.

Purpose of the Study:

• To propose and numerically investigate a modified multi-trench fiber (MTF) design incorporating gaps for leakage channels.
• To demonstrate the potential of this modified MTF for single-mode operation, enlarged mode area, and improved bending resistance.

Main Methods:

• Numerical investigation using the scalar finite-difference beam-propagation method algorithm.
• Analysis of a modified MTF design with varying high-index ring thickness, gap width, and bending orientation.

Main Results:

• Demonstrated potential for single-mode operation, mode area enlargement, and bending resistance.
• Achieved a high loss ratio (>50) between high-order and fundamental modes across a wide parameter range.
• Obtained an effective area of 920 μm² at 1050 nm with a 20 cm bend radius and a loss ratio >100.

Conclusions:

• The modified gap MTF design offers significant advantages in performance and fabrication tolerance.
• The proposed design is potentially manufacturable by modifying existing MTFs, suggesting practical viability.