Ultrahigh-speed phase demodulation of a Fabry-Perot sensor based on fiber array parallel spectral detection

Area of Science:

• Optics and Photonics
• Sensor Technology
• Signal Processing

Background:

• Fabry-Perot (F-P) interferometric sensors are crucial for various measurement applications.
• High-speed phase demodulation is essential for detecting dynamic events like ultrasonic waves and vibrations.
• Existing systems may face limitations in speed and sensitivity for high-frequency applications.

Purpose of the Study:

• To design and demonstrate an ultrahigh-speed phase demodulation system for F-P interferometric sensors.
• To achieve real-time, high-frequency phase demodulation for enhanced sensor performance.
• To enable applications in ultrasonic and high-frequency vibration detection.

Main Methods:

• Utilized a fiber array parallel spectral detection technique.
• Employed a high-power amplified spontaneous emission (ASE) source for broadband light.
• Integrated an arrayed waveguide grating (AWG) for spectral dispersion and parallel detection by 48 photodiodes.
• Implemented synchronous signal acquisition and real-time processing.

Main Results:

• Achieved a phase demodulation frequency of 200 kHz for the F-P cavity.
• Constructed a high-speed, low-resolution spectral detection and demodulation system.
• Demonstrated a length demodulation range of 60-700 µm for the F-P cavity.
• Attained a demodulation resolution as high as 0.22 nm.

Conclusions:

• The developed system offers ultrahigh-speed phase demodulation capabilities for F-P sensors.
• The system's high sensitivity and speed are suitable for ultrasonic and high-frequency vibration detection.
• This technology advances the potential for precise real-time monitoring of dynamic physical phenomena.