Microresonator devices lithographically introduced at the optical fiber surface.

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Microresonator devices are crucial for optical signal processing.
• Existing fabrication methods for surface nanoscale axial photonics (SNAP) microresonators have limitations in controlling radius variation.

Purpose of the Study:

• To introduce a novel, simple lithographic method for fabricating SNAP microresonators on optical fiber surfaces.
• To demonstrate the versatility of the method for creating microresonators with significant radius variations and explore their application as delay lines.

Main Methods:

• A focused CO2 laser beam is used to selectively remove polymer coating from optical fibers.
• Hydrofluoric acid etching is employed, utilizing the remaining coating as a mask.
• Complete removal of the coating yields silica bottle microresonators with controlled radius variations.

Main Results:

• Fabrication of a chain of five microresonators (1 mm long, 30 nm high) on a 125 µm fiber.
• Creation of a single microresonator (0.5 mm long, 291 nm high) on a 38 µm fiber.
• Demonstration of a rectangular SNAP microresonator as a miniature delay line with 1 ns delay for a 100 ps pulse, exhibiting negligible dispersion.

Conclusions:

• The developed lithographic method offers a straightforward approach to fabricating SNAP microresonators.
• This technique allows for greater control over fiber radius variations, from nanoscale to microscale, expanding SNAP technology capabilities.
• The fabricated microresonators show potential for applications such as miniature optical delay lines.