Microresonator devices lithographically introduced at the optical fiber surface

TL;DR

This paper introduces a simple lithographic technique for fabricating microresonators directly on optical fiber surfaces, enabling precise control over size and shape for applications like delay lines.

Contribution

A novel lithographic method for creating microresonators on optical fibers with nanoscale to microscale radius variations, expanding capabilities beyond previous approaches.

Findings

Fabricated chains of silica bottle microresonators with nanoscale radius variation.

Demonstrated a microresonator as a miniature delay line with negligible dispersion.

Achieved larger fiber radius variations than previous SNAP technology methods.

Abstract

We present a simple lithographic method for fabrication of microresonator devices at the optical fiber surface. First, we undress the predetermined surface areas of a fiber segment from the polymer coating with a focused CO2 laser beam. Next, using the remaining coating as a mask, we etch the fiber in a hydrofluoric acid solution. Finally, we completely undress the fiber segment from coating to create a chain of silica bottle microresonators with nanoscale radius variation (SNAP microresonators). We demonstrate the developed method by fabrication of a chain of five 1 mm long and 30 nm high microresonators at the surface of a 125 micron diameter optical fiber and a single 0.5 mm long and 291 nm high microresonator at the surface of a 38 micron diameter fiber. As another application, we fabricate a rectangular 5 mm long SNAP microresonator at the surface of a 38 micron diameter fiber and investigate its performance as a miniature delay line. The propagation of a 100 ps pulse with 1 ns delay, 0.035c velocity, and negligible dispersion is demonstrated. In contrast to the previously developed approaches in SNAP technology, the developed method allows the introduction of much larger fiber radius variation ranging from nanoscale to microscale.