Flexible demodulation for rotation-induced phase difference based on a phase-controlled microwave photonic filter

Area of Science:

• Photonics
• Inertial Navigation
• Optical Sensing

Background:

• Accurate rotation rate measurement is crucial for inertial navigation systems.
• The Sagnac effect is a fundamental principle for rotation sensing.

Purpose of the Study:

• To propose and validate a flexible measurement scheme for rotation rate based on a phase-controlled microwave photonic filter (MPF).
• To leverage the Sagnac effect for high-performance demodulation in rotation sensing.

Main Methods:

• Utilizing an orthogonal double-sideband (ODSB) modulator to generate optical signals.
• Employing a Sagnac loop and a linearly chirped fiber Bragg grating (LCFBG) to create a tunable MPF.
• Detecting rotation rate by monitoring frequency response shifts or power variations of the MPF.

Main Results:

• Demonstrated a maximum frequency shift of 1.7 GHz at 1 rad/s rotation rate.
• Achieved a scale factor of 0.016 mW/(rad/s) at 4 GHz.
• Showcased adjustable measurement sensitivity through polarization control and frequency selection.

Conclusions:

• The proposed MPF-based system provides a flexible and high-performance solution for rotation rate measurement.
• The method is suitable for various inertial navigation applications requiring precise rotation sensing.