An integrated monolithic photonic accelerometer with on-chip fringe-counting

Area of Science:

• Photonics
• Integrated Circuits
• Inertial Sensing

Background:

• Photonic integrated circuits (PICs) offer potential for precision inertial sensing.
• Existing photonic accelerometers face limitations in readout complexity, dynamic range, and validation.
• Integrated photonics remains an underexplored platform for high-performance accelerometers.

Purpose of the Study:

• To design, model, and experimentally characterize a novel integrated photonic accelerometer.
• To enhance the dynamic range of photonic accelerometers using phase-unwrapping techniques.
• To establish PICs as a viable platform for high-dynamic-range inertial sensors.

Main Methods:

• Monolithic integration of two Mach-Zehnder interferometers on a silicon-nitride chip.
• Implementation of an open-loop fringe-counting strategy with a quarter-wavelength inter-arm path-length offset.
• Utilizing ellipse-fitting-based phase-unwrapping for accurate phase recovery over an expanded measurement range.

Main Results:

• Achieved a measured noise floor of 2.0 µg/√Hz, with a pathway to ~10 ng/√Hz.
• Demonstrated a 39 dB improvement in dynamic range via phase-unwrapping compared to conventional interferometers.
• First demonstration of fringe-counting functionality on a monolithic PIC accelerometer chip.

Conclusions:

• Integrated photonics is a promising platform for high-dynamic-range inertial sensing.
• The developed chip-scale accelerometer design surpasses limitations of current technologies.
• This work establishes a new route for miniaturized, high-performance inertial sensors.