The Structural Defects and Optical Performance of Polarization-Maintaining Hollow-Core Photonic Bandgap fiber

Hollow core photonic bandgap fiber (HC-PBGF) has potential in the application of fiber optics gyroscopes (FOGs) for its properties of low nonlinearity, and excellent environmental adaptability. However, due to the structural complexity, the HC-PBGF is prone to defects during fabrication process, which will cause degradation of longitude uniformity and optical properties of fiber. The longitudinal non-uniformity of the structure limits the preparation length of HC-PBGF, while high-precision FOGs need to be made with long-distance and high-performance fibers. To facilitate the application of HC-PBGF in high-precision FOG, we studied the instability factors encountered in the fabrication process of polarization-maintaining (PM) HC-PBGF and the induced structural defects, including the fiber core, core-side hole, and fiber diameter defects. According to analyzing the optical performance variation to structural deformation rate, we conducted that the diameter defect has the greatest impact on the fiber properties, while the core-side hole defect has the weakest impact. Based on the fluctuations of optical performance, we revealed the structural deviation tolerance of PM HC-PBGF and provided theoretical reference for fiber fabrication.