Grover-Sagnac interferometer

Area of Science:

• Quantum optics
• Interferometry
• Linear optical quantum computing

Background:

• The Sagnac interferometer is a fundamental tool for measuring rotation and nonreciprocal phase shifts.
• Traditional Sagnac interferometers rely on beam splitters and detect phase shifts by monitoring power variations.
• Higher-dimensional quantum systems offer new possibilities for enhanced sensing and metrology.

Purpose of the Study:

• To demonstrate a nontraditional Sagnac interferometer design.
• To replace the conventional beam splitter with a linear-optical Grover multiport.
• To explore a new method for detecting nonreciprocal Sagnac phase shifts.

Main Methods:

• Implementation of a Sagnac interferometer utilizing a linear-optical Grover multiport instead of a beam splitter.
• Analysis of the output intensity to identify resonance phenomena.
• Characterization of the resonance structure and its dependence on the nonreciprocal phase shift.

Main Results:

• A pole at the origin of the device parameter space was created, leading to a resonance in the output intensity.
• The resonance structure was found to be solely dependent on the nonreciprocal phase acquired in the Sagnac loop.
• A novel method for detecting nonreciprocal phase shifts was established, utilizing the width of the resonance peak or dip.

Conclusions:

• The Grover multiport-based Sagnac interferometer offers a distinct approach to measuring nonreciprocal phase shifts.
• This method allows for phase extraction from resonance width, providing an advantage over traditional power-based detection.
• The study highlights potential metrological applications and discusses the impact of system losses.