传输可见光的空芯光子带隙光纤的研究

利用全矢量平面波展开法(FVPWM)对采用改进的两次堆积法制备的空芯光子带隙光纤进行了数值模拟.在特定传播常数β下，光纤在500—1000 nm的波段内出现多条宽窄不同的有效光子带隙.依据有效折射率的不同，部分带隙中的空气-导模将以不同的形式存在.经过实验测试，发现测得的带隙位置相对于模拟结果向短波段发生了较明显的移动，主要原因被认为是光纤结构的纵向不均匀性和包层节点处间隙孔的存在.关键词：空芯光子带隙光纤全矢量平面波展开法有效光子带隙空气-导模

Investigation of hollow-core photonic band-gap fiber at visible wavelengths

Based on full-vector plane-wave method (FVPWM), the hollow-core photonic band-gap fiber (HC-PBGF) fabricated using the improved twice stack-and-draw technique has been simulated. Under given values of propagation constant β, some valid photonic band-gaps (PBGs) with different sizes will emerge within the wave band of 500—1000 nm. For different values of the effective refractive index, the air-guided modes can exist in different forms in part of PBGs. Comparing the experimental data with the simulation result, we have discovered that the measured positions of PBGs are shifted to shorter wavelengths distinctly. The primary reasons are considered to be the structure asymmetry along longitudinal direction and the existence of interstitial holes at nodes in the cladding region.