Efficient mid-infrared light coupling into a single-mode optical fiber

Area of Science:

• Photonics and Optical Engineering
• Fiber Optics Communications

Background:

• Efficient coupling between optical fibers is crucial for various photonic applications.
• Existing coupling methods often suffer from sensitivity to transverse misalignment.
• Photonic lanterns offer potential for mode manipulation but require mode-selectivity.

Purpose of the Study:

• To demonstrate a mode-selective photonic lantern as an efficient, transverse offset-tolerant coupling mechanism.
• To validate the principle of selective excitation of the fundamental mode.
• To explore its potential for laser pigtailing and fiber-to-fiber coupling.

Main Methods:

• Design of a photonic lantern using indium fluoride optical fibers.
• Fabrication of a prototype photonic lantern.
• Experimental testing at a wavelength of 3.34 μm, including transverse offset tolerance evaluation.
• Comparison of experimental results with simulations.

Main Results:

• Successful demonstration of a mode-selective photonic lantern.
• The device exhibits excellent transverse offset tolerance.
• Experimental results closely match simulation predictions, confirming device feasibility.

Conclusions:

• The mode-selective photonic lantern provides an efficient and robust coupling solution.
• This technology is highly promising for applications like laser pigtailing.
• It enables effective coupling between different fiber types, including hollow-core and single-mode fibers.