Twisted Fiber Bragg Gratings as a Polarization-Insensitive Element

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Fiber Bragg gratings (FBGs) are crucial optical components.
• Polarization dependence limits the precision of FBG sensors.
• Current fabrication methods often result in polarization-sensitive gratings.

Purpose of the Study:

• To develop an original method for fabricating Bragg gratings with minimized polarization dependence.
• To investigate the effectiveness of inscribing Bragg structures in pre-twisted optical fibers.
• To enhance the performance of FBGs for high-precision sensing applications.

Main Methods:

• Utilized the point-by-point fabrication technique.
• Employed femtosecond laser radiation for inscription.
• Introduced a pre-twisted optical fiber structure to embed the Bragg grating.

Main Results:

• Demonstrated a significant reduction in the polarization dependence of Bragg gratings.
• The polarization dependence of the reflection level decreased by at least an order of magnitude.
• The polarization dependence of the Bragg wavelength decreased by three times compared to straight FBGs.

Conclusions:

• The proposed method effectively minimizes polarization dependence in Bragg gratings.
• Pre-twisted fiber Bragg gratings offer improved stability and accuracy.
• This technique is suitable for producing high-precision Bragg sensors for various applications.