Birefringence characterization in a dual-hole microstructured optical fiber using an OFDR method

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Microstructured optical fibers (MOFs) offer unique light-guiding properties.
• Birefringence in MOFs is critical for polarization control and sensing applications.
• Accurate characterization of group birefringence is essential for designing polarization-maintaining fibers.

Purpose of the Study:

• To numerically calculate and experimentally characterize the group birefringence in a dual-hole microstructured optical fiber.
• To demonstrate the efficacy of optical frequency domain reflectometry (OFDR) for precise birefringence measurement.
• To validate experimental results against theoretical simulations.

Main Methods:

• Numerical simulation of birefringence in a dual-hole MOF.
• Experimental characterization using a polarized coherent optical frequency domain reflectometry (OFDR) system.
• Analysis of Fresnel reflection peaks and beat frequency differences between polarized modes (LP01x and LP01y).

Main Results:

• The polarized LP01x and LP01y modes exhibit different group velocities due to asymmetric dual air holes.
• Experimental group birefringence of -9.68×10⁻⁴ was measured at a 6.2 m fiber end.
• This experimental value closely matches the theoretically simulated birefringence of -9.54×10⁻⁴.

Conclusions:

• The OFDR method provides an accurate and flexible approach for group birefringence characterization in MOFs.
• The study confirms the feasibility of using OFDR for complex fiber structures.
• This technique is valuable for the development and quality control of advanced optical fibers.