INVESTIGATION OF LARGE MODE AREA PIXELATED BRAGG FIBERS FOR LASER APPLICATIONS

Abstract

This paper examines the optical per- formance of a Large Mode Area (LMA) Pixelated Bragg Fiber (PiBF), i.e., Fiber A, for applications in high-power lasers. The study employs COMSOL Multiphysics simulations to investigate key performance parameters like attenuation, overlap integral, effective refractive index, and mode field diameter (MFD) between the wavelengths of 1000 nm and 1800 nm. The findings show that Fiber A has low attenuation for most of the working range, with a sudden spike near 1200 nm, which is at the edge of the photonic bandgap. The overlap integral is highest at 1140 nm, which is also where the fundamental mode is best confined, and the effective refractive index is linearly decreasing as a function of wavelength with good guiding conditions. Moreover, the simulations also explored the impact of various pixel diameter and pixel-to-cladding refractive index differences, and they demonstrated that these parameters are capable of shifting the resonance wavelengths and enhancing the performance of the fiber. The findings verify the fiber for high-power laser applications, presenting a compromise between large mode area and single-mode operation.