Comparative Study of Loss Characteristics in Mid-IR Hollow Metal-Core Fibers Using Au, Ag, and Al
摘要
This study presents a thorough numerical investigation of hollow metal-core fibers (HMCFs) operating in the mid-infrared (MIR) spectral range of 3–10 µm. Three cladding metals, gold (Au), silver (Ag), and aluminum (Al), were analyzed to assess their impact on optical performance. The finite-difference time-domain (FDTD) method was employed using Lumerical 2023 R2.3, with the fiber geometry optimized by varying the core diameter, metal wire arrangement, and spacing. The confinement loss trends of the three metals exhibited similar patterns. Silver achieved the least loss, 2.0899 × 10−8 dB/m, aluminum showed the highest loss value, 6.5819 × 10−8 dB/m, and gold presented an intermediate loss value, 4.0544 × 10−8 dB/m. Interestingly, the lowest confinement loss for all metals occurred at a wavelength of approximately 8.9 µm. In contrast to other studies that have focused on these metals, which have tended to examine individual metal structures or a limited spectral range, this work presents a comprehensive comparison across the full MIR band. The results highlight the potential of using aluminum as a low-cost and feasible alternative to noble metals, offering similar performance in mid-IR waveguiding devices. Future work will include experimental fabrication to verify the numerically calculated results and further investigate aluminum-based designs to achieve scalable infrared photonic devices.