All-solid very large mode area ytterbium-doped silica microstructured fiber based on accurate control on cladding...

Area of Science:

• Materials Science
• Optics and Photonics
• Fiber Optics

Background:

• Developing large mode area (LMA) fibers is crucial for high-power fiber lasers.
• Existing methods for fabricating LMA fibers can be complex and may compromise beam quality.

Purpose of the Study:

• To present a new, simplified approach for fabricating very large mode area silica-based microstructured Ytterbium (Yb)-doped fibers.
• To demonstrate precise control over the cladding index for enhanced fiber performance.

Main Methods:

• Utilized a passively doped cladding (PDC) method with periodically arranged low-index Fluorine-doped silica inclusions.
• Achieved highly accurate control of the cladding index (1 × 10^-5) with a very low filling ratio (0.088).
• Fabricated two fibers with 127μm and 50μm core diameters from a single preform.

Main Results:

• Successfully fabricated Yb-doped fibers with large mode areas.
• Verified robust single-mode behavior at 1064nm for the 50μm core diameter fiber.
• Demonstrated precise cladding index control via the PDC method.

Conclusions:

• The novel PDC approach offers a simplified fabrication process for LMA fibers.
• This method is highly suitable for producing Yb-doped fibers for high-power fiber laser applications.
• The all-solid structure and precise index control contribute to robust single-mode operation.