Fiber-optic Michelson magnetic field sensor based on a mechanical amplifier structure.

Area of Science:

• Optoelectronics
• Sensor Technology
• Materials Science

Background:

• Magnetic field sensors are crucial for various applications, including navigation, medical imaging, and industrial monitoring.
• Existing sensors often face limitations in sensitivity, response time, or complexity.
• Developing novel sensor architectures is essential for enhanced performance.

Purpose of the Study:

• To propose and experimentally demonstrate a novel magnetic field sensor.
• To leverage a mechanical amplifier structure integrated with a Michelson interferometer for enhanced sensitivity.
• To evaluate the sensor's performance characteristics, including sensitivity, minimum detectable field, and response time.

Main Methods:

• The sensor utilizes a 3x3 coupler-based Michelson interferometer.
• A mechanical amplifier structure featuring a Terfenol-D (TbDyFe) rod wrapped with polarization-maintaining (PM) fiber acts as the transducer.
• Deformation of the TbDyFe rod by the magnetic field is amplified and transferred to the PM fiber, inducing a phase shift.

Main Results:

• The sensor demonstrated an average magnetic field sensitivity of 0.4471 V/µT (rms).
• Phase shift sensitivity was measured at 0.2581 rad/µT (rms).
• A minimum detectable magnetic field of 0.0755 nT/√Hz (rms) and a maximum response time of 22.77 ms were achieved.

Conclusions:

• The proposed magnetic field sensor offers a simple design and fast response.
• Its high sensitivity and low detectable magnetic field make it suitable for weak magnetic field detection.
• This technology holds promise for advancements in magnetic sensing applications.