A Mini-Two-Path Mach-Zehnder Interferometer Sensor with High Curvature Sensitivity Based on Four-Mode Fiber

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Interferometry

Background:

• Mach-Zehnder interferometers (MZIs) are widely used for sensing applications.
• Improving sensitivity and reducing cross-sensitivity in MZI sensors remain key challenges.
• Specialty optical fibers offer unique properties for enhanced sensor performance.

Purpose of the Study:

• To propose and demonstrate a novel hybrid mini-two-path Mach-Zehnder interferometer (MTP-MZI) sensor.
• To investigate the sensor's performance for curvature and temperature detection.
• To achieve high sensitivity and mitigate cross-sensitivity in fiber optic sensing.

Main Methods:

• Fabrication of a hybrid MTP-MZI sensor using single-mode fiber (SMF) and four-mode fiber (FMF).
• Utilizing arc discharge technology for robust fusion and coupling of fiber paths.
• Experimental characterization of curvature and temperature sensing capabilities.

Main Results:

• The MTP-MZI sensor demonstrated a maximum curvature sensitivity of 168.41 dB/m⁻¹ within a 0-0.091 m⁻¹ range.
• This represents the highest reported curvature sensitivity for intensity-modulated MZI fiber sensors.
• A temperature sensitivity of 78 pm/°C was observed in the 30-65 °C range, enabling effective cross-sensitivity mitigation.

Conclusions:

• The developed hybrid MTP-MZI sensor exhibits excellent sensitivity for curvature detection.
• The distinct sensing responses to curvature and temperature allow for effective cross-sensitivity management.
• This work provides a foundation for developing advanced fiber optic sensors using hybrid structures and specialty fibers.