Mode power distribution effect in white-light multimode fiber extrinsic Fabry-Perot interferometric sensor systems

Area of Science:

• Optics and Photonics
• Fiber Optic Sensors
• Interferometry

Background:

• Multimode fiber extrinsic Fabry-Perot interferometric (MMF-EFPI) sensors are used in various applications.
• Spectral fringe phase is a key parameter for signal demodulation in these sensors.
• Variations in mode power distribution (MPD) are known to affect optical systems.

Purpose of the Study:

• To investigate the impact of mode power distribution (MPD) variations on the spectral fringe phase in MMF-EFPI sensor systems.
• To identify the underlying mechanism causing phase shifts due to MPD variations.
• To assess the potential for measurement errors in white-light MMF-EFPI sensors resulting from MPD changes.

Main Methods:

• Theoretical analysis of light propagation and mode coupling in MMF-EFPI systems.
• Experimental measurements of spectral fringe phase under varying MPD conditions.
• Simulation of fringe pattern changes based on theoretical models.

Main Results:

• MPD variations significantly alter the spectral fringe phase of MMF-EFPI sensors.
• Different fiber modes introduce distinct extra phase shifts due to mode coupling at the reflective surface.
• The dependence of fringe patterns on MPD can introduce errors in white-light sensor signal demodulation.

Conclusions:

• MPD is a critical factor influencing the accuracy of MMF-EFPI sensors.
• Understanding and mitigating MPD effects are essential for reliable MMF-EFPI sensor measurements.
• Future research should focus on MPD stabilization or compensation techniques for MMF-EFPI systems.