Single-mode fiber microlens with controllable spot size.

Area of Science:

• Optoelectronics
• Fiber Optics
• Materials Science

Background:

• Microlenses are crucial for manipulating light in fiber optic systems.
• Tapered fibers offer unique properties for optical device fabrication.
• Precise control over light focusing is essential for advanced applications.

Purpose of the Study:

• To present a novel method for fabricating microlenses on tapered single-mode fibers.
• To demonstrate the ability to control the focused spot size of the microlens.
• To achieve significant reduction in the fiber mode radius.

Main Methods:

• Symmetrical tapering of fiber cladding using an evaporating ammonium bifluoride solution.
• Melting a hemispheric lens onto the taper tip using a CO(2) laser.
• Fabrication of microlenses on single-mode optical fibers.

Main Results:

• The developed microlens fabrication method successfully controlled the lens spot size.
• The fiber mode radius was reduced to 40% of its original value.
• Theoretical calculations for focused spot size showed excellent agreement with experimental outcomes.

Conclusions:

• The novel method provides effective control over microlens spot size on tapered fibers.
• This technique offers a viable approach for enhancing optical performance in fiber-based devices.
• The results validate the theoretical model and experimental procedure for microlens fabrication.