Thermal tuning of planar Bragg gratings in silicon-on-insulator rib waveguides

The Bragg grating forms an essential element in optical telecommunication and sensing applications. In the case of integrated optics, it is necessary to incorporate the grating into a waveguide during device fabrication. Specifically for silicon photonics this process is deemed necessary to be compatible with standard processing technology. We have recently developed a method for the fabrication of Bragg gratings via self-ion implantation of silicon-on-insulator (SOI) waveguides, such that the surface of the waveguide remains planar. This has significant benefits for a number of devices especially those requiring subsequent wafer bonding. Here we report work that shows the ability of these devices to be thermally tuned. As the waveguides are heated, a positive shift in the resonant wavelength is induced due to the temperature dependence of the index of refraction and thermal expansion of the silicon. The observed shift is 0.080 nm/degree, in good agreement with theoretical prediction. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim