Highly Sensitive Strain Sensor Based on a Novel Mach-Zehnder Interferometer with TCF-PCF Structure.

Area of Science:

• Optoelectronics
• Fiber Optics Sensors

Background:

• Fiber optic sensors are crucial for remote and real-time monitoring.
• Mach-Zehnder interferometers (MZIs) offer high sensitivity but require optimization for strain sensing.

Purpose of the Study:

• To demonstrate a novel, highly sensitive strain sensor.
• To investigate the strain properties and sensitivity of a fiber in-line MZI.
• To explore the effect of MZI length on strain sensitivity.

Main Methods:

• Fabrication of an in-line Mach-Zehnder interferometer (MZI) by splicing photonic crystal fiber (PCF) and thin core fiber (TCF) between single mode fibers (SMFs).
• Experimental characterization of the MZI's fringe visibility and strain response.
• Analysis of strain sensitivity across different MZI lengths at the 1550 nm band.

Main Results:

• Achieved a high fringe visibility of 20 dB in air.
• Demonstrated a strain sensitivity of -1.95 pm/με within the 0 to 4000 με range.
• Observed a weak dependence of strain sensitivity on MZI length, with values ranging from -1.63 pm/με to -1.78 pm/με for different PCF lengths.

Conclusions:

• The developed fiber in-line MZI sensor exhibits high sensitivity and good fringe visibility.
• The sensor design is simple, compact, and suitable for precise strain monitoring.
• Sensitivity is minimally affected by the MZI's physical length, indicating robust performance.