Work

Widely FSR tunable high Q-factor microresonators formed at the intersection of straight optical fibers

Year: 2025

Type: article

Abstract: We present a class of high-Q tunable microresonators formed at the intersection of two straight silica optical fibers, whose free spectral range (FSR) can be widely tuned by fiber rotation. The proposed configuration avoids the limitations of traditional monolithic microresonators that lack FSR tunability required for a wide range of photonic applications. Using small rotation angles (1–15 mrad), we demonstrate a tunability of the FSR from 2 pm to 10 pm, enabled by microscale fiber displacements that reshape the resonator profile over millimeter scales. The proposed approach minimizes mechanical stress, supports miniaturization, and is suitable for integration with MEMS. It paves the way for the fabrication of tunable delay lines, ultralow repetition rate broadband frequency comb generators, and nonlocal optofluidic sensors on a chip.

Source: Optica

DOI: 10.1364/optica.565224

Authors: Isha Sharma, Misha Sumetsky

Language: English

Topic: Photonic and Optical Devices

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,208

Funders: Leverhulme Trust, Engineering and Physical Sciences Research Council

Awards: Picometre Surface Nanoscale Axial Photonics (PicoSNAP), Advanced Optical Frequency Comb Technologies and Applications, G7993323644