Thermo-Optic Switching Effect Based on Fluid-Filled Photonic Crystal Fiber

We report a thermo-optic switching effect with a high extinction ratio of 30 dB by means of filling a fluid into air holes of a solid-core photonic crystal fiber (PCF). Such an effect can perform a turn on–off operation of the transmitted light via a small temperature adjustment of $\pm$10 $^{\circ}\hbox{C}$. The switching function attributes to the absorption of the filled fluid in combination with the interaction between the core mode and the excited “fluid rod” modes, resulting from the thermo-optic effect of the filled fluid.