Optical cavity reaching 10^-16 frequency stability with compact optical circulator based in-coupling optics.

Area of Science:

• Physics
• Optical Engineering
• Space Technology

Background:

• Future space missions require highly stable and compact optical frequency references.
• Optical cavities are suitable for relative frequency reference applications.
• Improving in-coupling optics is crucial for enhancing optical cavity performance, compactness, and robustness.

Purpose of the Study:

• To present a novel fiber-coupled circulator-based in-coupling method for high-finesse optical cavities.
• To evaluate the performance of this new in-coupling technique compared to the traditional free-beam method.
• To assess the impact of the circulator on the frequency stability of the optical cavity.

Main Methods:

• Implementation of a fiber-coupled circulator-based in-coupling board.
• Integration with an extensively characterized crossed cavity setup.
• Comparison with the commonly used free-beam in-coupling technique.

Main Results:

• Achieved a frequency stability of 5.5×10^-16 Hz^-1/2 at 1 Hz.
• Observed only a slight degradation in frequency stability below the mHz range.
• No circulator-induced instabilities were detected.

Conclusions:

• The fiber-coupled circulator in-coupling method is a viable alternative to free-beam techniques for high-finesse optical cavities.
• This approach maintains high frequency stability, essential for demanding applications like space missions.
• The developed in-coupling board offers a compact and robust solution without compromising optical cavity performance.