Broadband thermo-optic switch based on a W2 photonic crystal waveguide

Broadband thermo-optic switch based on an ultra-compact W2 photonic crystal waveguide (PCW) is demonstrated with an integrated titanium/aluminum microheater on its surface. The operating principle relies on shifting a transmission-dip caused by the enhanced coupling between the defect modes in W2 PCW. As a result, broadband switching functionality with larger extinction ratio can be attained. Moreover, microheaters with different width are evaluated by the power consumptions and heating transfer efficiency, and an optimized slab microheater is utilized. Finally, switching functionality with bandwidth up to 24 nm (1557 similar to 1581 nm) is measured by the PCW with footprint of only 8. mx17.6 mu m, while the extinction ratio is in excess of 15 dB over the entire bandwidth. What's more, the switching speed is obtained by the measurement of alternating current modulation. Response time for this thermo-optic switch is 11.0 +/- 3.0 mu s for rise time and 40.3 +/- 5.3 mu s for fall time, respectively.