Highly sensitive vibration sensor based on the dispersion turning point microfiber Mach-Zehnder interferometer.

Area of Science:

• Optoelectronics
• Fiber optics sensors
• Interferometry

Background:

• Mach-Zehnder interferometers (MZIs) are widely used for sensing applications.
• Microfiber-based sensors offer enhanced sensitivity and miniaturization potential.
• Dispersion turning point (DTP) phenomena in optical fibers can be exploited for novel sensing mechanisms.

Purpose of the Study:

• To introduce and characterize a highly sensitive vibration sensor based on a DTP microfiber Mach-Zehnder interferometer.
• To investigate the axial strain and vibration sensing performance of the proposed sensor.
• To demonstrate the sensor's capability for micro-vibration monitoring.

Main Methods:

• Theoretical analysis of spectrum evolution in microfiber MZIs under axial strain.
• Fabrication of DTP microfibers using electrode discharge and fused taper methods.
• Experimental investigation of axial strain sensitivity and vibration sensing performance.

Main Results:

• Achieved a maximum axial strain sensitivity of -45.55 pm/µɛ at ~1550 nm for a ~2.2 µm diameter DTP microfiber.
• Designed and implemented a vibration sensor using a DTP microfiber integrated into a cantilever beam.
• Demonstrated vibration signal monitoring from 30-3500 Hz with a maximum SNR of ~75 dB at 52 Hz.
• Measured acceleration sensitivity as high as 0.764 V/g at 45 Hz.

Conclusions:

• The DTP microfiber Mach-Zehnder interferometer exhibits excellent performance for axial strain sensing.
• The developed sensor demonstrates high sensitivity and a wide frequency response for micro-vibration detection.
• The proposed sensor shows significant potential for applications in micro-vibration sensing fields.