Fiber Fabry-Perot interferometers with very low polarization sensitivity

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Fiber Fabry-Perot interferometers (FFPIs) are sensitive to input polarization.
• High polarization sensitivity limits FFPI applications, especially in precise measurements.
• Existing FFPIs often exhibit significant polarization-dependent loss (PDL).

Purpose of the Study:

• To reduce the sensitivity to input polarization in long-cavity, high-finesse FFPIs.
• To investigate the use of very-low-birefringence fibers for FFPI construction.
• To enable high-resolution measurement of polarization-mode dispersion (PMD).

Main Methods:

• Utilized very-low-birefringence fibers in the construction of long-cavity (1 cm to 5 m) FFPIs.
• Characterized the passband amplitude variation in response to input polarization.
• Employed scanning FFPIs for high-resolution measurements.

Main Results:

• Reduced polarization sensitivity from over 20 dB to 0.2–0.6 dB in passband amplitude variation.
• Demonstrated the effectiveness of very-low-birefringence fibers in mitigating polarization effects.
• Achieved high-resolution measurement capabilities for polarization-mode dispersion.

Conclusions:

• Very-low-birefringence fibers significantly enhance FFPI performance by reducing polarization sensitivity.
• Scanning FFPIs utilizing these fibers are suitable for high-resolution PMD measurements in optical fibers.
• This work opens avenues for more robust and precise fiber-optic sensing and metrology applications.