An Honglin, Fleming Simon
Institute of Photonics and Optical Science, School of Physics, Physics Building A28, the University of Sydney, NSW 2006, Australia.
Opt Express. 2012 Mar 26;20(7):7436-44. doi: 10.1364/OE.20.007436.
Twin-hole fibers were thermally poled with different internal electrode configurations, including having only one anode wire in the hole, two anode wires in the two holes, one cathode wire, and two cathode wires in the holes, in comparison to the conventional one anode wire and one cathode wire combination. Second harmonic microscopy was utilized to visually reveal the spatial distribution and to measure the magnitude of the induced second-order optical nonlinearity within the poled fibers. It was found that both one- and two-anode configurations resulted in strong nonlinearity comparable with the conventional case but the two-anode configuration was more reproducible than the one-anode case; for the one-cathode-wire and two-cathode-wire configuration, strong nonlinearity in a ring shape concentric with the fiber outer surface was induced as if the cathode metal wire were in the center of the twin-hole fiber rather than substantially offset. These new results provide strong support for the proposed model of a "self-adjustment" mechanism and point the way to simplified and more repeatable experimental techniques.
与传统的单阳极线和单阴极线组合相比，双孔光纤采用了不同的内部电极配置进行热极化，包括孔内仅有一根阳极线、两个孔内各有两根阳极线、一根阴极线以及两个孔内各有两根阴极线。利用二次谐波显微镜直观地揭示了极化光纤内二阶光学非线性的空间分布并测量其大小。结果发现，单阳极和双阳极配置均产生了与传统情况相当的强非线性，但双阳极配置比单阳极配置更具可重复性；对于单阴极线和双阴极线配置，在与光纤外表面同心的环形区域诱导出了强非线性，就好像阴极金属线位于双孔光纤的中心而非明显偏移一样。这些新结果为所提出的“自我调整”机制模型提供了有力支持，并为简化且更具可重复性的实验技术指明了方向。
