Cascaded interferometers structure based on dual-pass Mach-Zehnder interferometer and Sagnac interferometer for...

Area of Science:

• Optical sensing
• Fiber optics
• Interferometry

Background:

• Accurate simultaneous measurement of strain and lateral stress is crucial for structural health monitoring and material science.
• Existing methods often face limitations in sensitivity or dual-parameter discrimination.

Purpose of the Study:

• To propose and demonstrate a novel cascaded interferometers structure for simultaneous strain and lateral stress measurement.
• To leverage dual interference mechanisms for enhanced sensing capabilities.

Main Methods:

• A cascaded interferometer configuration integrating a Sagnac interferometer (SI) and a dual-pass Mach-Zehnder interferometer (DP-MZI).
• Incorporation of polarization-maintaining photonic crystal fiber (PM-PCF) within the SI sensing loop.
• Analysis of the combined reflection spectrum comprising SI envelope and DP-MZI fringes.

Main Results:

• The SI demonstrated sensitivity of 1.28 nm/kPa for lateral stress and 0.78 pm/µε for strain.
• The DP-MZI achieved sensitivities of -0.009 nm/kPa for lateral stress and 5.65 pm/µε for strain.
• Successful simultaneous measurement of both parameters with high accuracy was demonstrated.

Conclusions:

• The proposed cascaded interferometer structure effectively enables simultaneous measurement of strain and lateral stress.
• The dual interference approach offers a promising pathway for advanced optical sensing applications.
• This configuration provides a robust platform for high-accuracy dual-parameter sensing in various fields.