Tunable fiber Fabry-Perot cavities with high passive stability.

Area of Science:

• Optics and Photonics
• Mechanical Engineering
• Materials Science

Background:

• High-finesse optical cavities are crucial for precision measurements and quantum technologies.
• Existing Fabry-Perot cavities often face challenges with mechanical stability and tunability.
• Monolithic designs offer potential improvements in stability and alignment.

Purpose of the Study:

• To present novel monolithic fiber Fabry-Perot cavities (FFPCs) with enhanced passive mechanical stability.
• To demonstrate fast, wide-range frequency tuning capabilities using integrated piezoelectric elements.
• To characterize the frequency noise and stability of these FFPCs.

Main Methods:

• Fabrication of three monolithic fiber Fabry-Perot cavities with mirrors fixed in slotted glass ferrules.
• Integration of piezoelectric elements for active frequency tuning in two designs.
• Experimental characterization of cavity resonance locking bandwidths and frequency noise spectrum.

Main Results:

• Achieved high passive mechanical stability, enabling sub-Hertz feedback bandwidths.
• Demonstrated fast tuning over the entire free-spectral range.
• Suppressed root-mean-square frequency fluctuations to ~2% of the cavity linewidth.
• Identified thermal noise as the dominant noise source at mechanical resonances.

Conclusions:

• The developed FFPCs exhibit excellent mechanical stability and tunability.
• These compact devices are suitable for diverse applications including sensing, optical filtering, and quantum interfaces.
• The design overcomes limitations of traditional cavities, paving the way for improved optical systems.