Fiber-tip dual-cavity Fabry-Perot sensor for weak magnetic-field measurement enabled by Vernier-like envelope...

Area of Science:

• Optoelectronics
• Sensor Technology
• Materials Science

Background:

• Weak magnetic field sensing is crucial for various applications.
• Fabry-Perot interferometers offer high sensitivity but require miniaturization.
• Integrating magnetic elements with optical cavities presents a sensing challenge.

Purpose of the Study:

• To demonstrate a fiber-tip weak magnetic-field sensor.
• To utilize a dual-cavity Fabry-Perot interferometer for enhanced sensitivity.
• To investigate the sensor's performance under different magnetic field conditions.

Main Methods:

• Fabrication of a fiber-tip sensor with a polydimethylsiloxane (PDMS) diaphragm and a magnetic disk.
• Utilizing a dual-cavity Fabry-Perot interferometer to convert magnetic force into air-cavity modulation.
• Employing Vernier-like envelope tracking for signal demodulation and analysis.

Main Results:

• Achieved sensitivities of -3.963 nm/mT (repulsive) and 2.937 nm/mT (attractive) over a 0-5 mT range.
• Demonstrated hysteresis and baseline drift characteristics of the sensor.
• Evaluated Fast Fourier Transform (FFT)-derived optical path difference and temperature compensation using a Fiber Bragg Grating (FBG).

Conclusions:

• The fiber-tip dual-cavity Fabry-Perot interferometer sensor is effective for weak magnetic field detection.
• The sensor design offers high sensitivity and potential for practical applications.
• Further analysis confirmed the sensor's stability and temperature compensation capabilities.