Temperature sensing by mode-mode interference in birefringent optical fibers

Area of Science:

• Optics and Photonics
• Sensor Technology
• Materials Science

Background:

• Fiber-optic sensors offer advantages in harsh environments.
• Mode-mode interference in optical fibers is a known sensing principle.
• Strongly birefringent fibers exhibit unique polarization properties.

Purpose of the Study:

• To investigate the performance of single-mode fiber-optic sensors based on mode-mode interference.
• To quantify the temperature and pressure sensitivities of these sensors.
• To evaluate the reduction in cross-sensitivity using specific fiber types.

Main Methods:

• Utilizing the mode-mode interference of two orthogonal linear polarizations of the HE(11) mode.
• Employing strongly birefringent single-mode fibers with high internal stress.
• Calculating the sensitivities of one-fiber interferometers.

Main Results:

• Demonstrated significant reduction in temperature sensitivity (factor of 50) compared to two-fiber systems.
• Achieved a substantial decrease in pressure sensitivity (factor of 7.3 x 10^3).
• Overall cross-sensitivity reduced by a factor of 150.

Conclusions:

• Single-mode fiber-optic sensors utilizing mode-mode interference offer enhanced performance.
• High internal stress in birefringent fibers effectively minimizes cross-sensitivity.
• These sensors present a promising solution for applications requiring high measurement accuracy.