Polarization-maintaining and single-mode large mode area pixelated Bragg fiber

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Pixelated Bragg fibers offer large mode areas but often lack polarization-maintaining capabilities.
• Achieving both large mode area and polarization maintenance in all-solid fibers is a significant challenge.

Purpose of the Study:

• To report on a novel large mode area pixelated Bragg fiber with polarization-maintaining properties.
• To investigate the feasibility of using boron-doped rods to achieve polarization maintenance while retaining single-mode behavior.

Main Methods:

• Fabrication of an all-solid pixelated Bragg fiber.
• Replacement of some high refractive index rods with boron-doped rods.
• Characterization of the fiber's mode field diameter, polarization extinction ratio, and bending loss.

Main Results:

• The realized all-solid fiber has a core diameter of 35 µm.
• A circular fundamental mode with a 25 µm mode field diameter was achieved around 1 µm wavelength.
• A polarization extinction ratio of 30 dB was obtained, indicating strong polarization maintenance.
• The fiber demonstrated single-mode behavior and bendability to a 20 cm radius.
• Fundamental mode losses were measured to be lower than 0.3 dB/m.

Conclusions:

• The developed boron-doped pixelated Bragg fiber successfully achieves both large mode area and polarization maintenance.
• This fiber design is suitable for applications requiring robust single-mode operation and polarization stability.
• The fiber's bendability and low loss characteristics make it promising for practical optical systems.