Lithium niobate photonic crystal wire cavity: Realization of a compact electro-optically tunable filter

We report an electro-optically tunable filter using a lithium niobate photonic crystal cavity configuration with an efficient optical guiding geometry. The compact device (5.5 mu m x 2.8 mu m) was made on a hybrid waveguide combining an annealed proton exchange waveguide and a ridge waveguide realized by focused ion beam with vertically deposited electrodes. Due to the slow light and nonlinear effect in lithium niobate photonic crystal, experimental results show an enhanced tunability of similar to 0.56 nm/V. This compact tunable photonic crystal cavity demonstration opens the path for the development of micro and nano-scale low-power driving active photonic devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4760224]