High Q-factor reconfigurable microresonators induced in side-coupled optical fibres

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Quantum Optics

Background:

• High Q-factor optical microresonators are crucial for optical signal processing, sensing, and fundamental science.
• The lack of free spectral range (FSR) tunability in traditional microresonators limits their application scope.
• Mechanical reconfigurability is highly desirable for advanced optical devices.

Purpose of the Study:

• To experimentally demonstrate a novel method for creating mechanically reconfigurable optical microresonators.
• To achieve tunable free spectral range (FSR) in high Q-factor whispering gallery mode microresonators.
• To explore the potential applications of these novel microresonators.

Main Methods:

• Side-coupling of coplanar bent optical fibers to induce whispering gallery mode (WGM) microresonators.
• Mechanically adjusting the curvature radius of optical fibers to alter microresonator dimensions and FSR.
• Developing theoretical models to describe microresonator formation and properties.

Main Results:

• Successfully fabricated high Q-factor WGM optical microresonators using bent optical fibers.
• Demonstrated mechanical reconfigurability of microresonator dimensions (millimeter to 100-micron order) and FSR (picometer to ten picometer order).
• Developed a theory that reasonably agrees with experimental observations.

Conclusions:

• The developed technique enables the creation of fully mechanically reconfigurable optical microresonators.
• These novel microresonators offer tunable FSR, overcoming limitations of static monolithic designs.
• Potential applications include cavity quantum electrodynamics (QED), optomechanics, tunable frequency combs, tunable lasing, and optical pulse processing.