Thermooptically Tuned Photonic Crystal Waveguide Silicon-on-Insulator Mach–Zehnder Interferometers

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Ultracompact thermooptically tuned photonic crystal waveguide (PCW) silicon-on-insulator Mach–Zehnder interferometers (MZIs) have been proposed and fabricated. A novel thermal design was employed to improve the device switching performance. Both steady-state and transient thermal analyses were performed to evaluate the thermal performance of the thermooptic MZIs. A switching time less than 20 <emphasis><formula formulatype="inline"><tex>$\mu$</tex> </formula></emphasis>s has been experimentally achieved, which clearly demonstrated the speed advantage using the new heating approach. The active length of the PCW-based MZIs was 80 <emphasis><formula formulatype="inline"><tex>$\mu$</tex> </formula></emphasis>m, nearly one order of magnitude shorter than the conventional silicon waveguide-based MZIs. A maximum modulation depth of 84% for a switching power of 78 mW was obtained at a wavelength of 1548 nm. </para>