Numerical design optimization of ridge waveguide for athermal integrated Bragg grating

The resonant wavelength of photoinduced Bragg gratings in all silica ridge waveguides exhibits a temperature drift of up to 0.013 nm//spl deg/C. Previously, we have shown that by covering the silica waveguide core with a special polymer, the temperature sensitivity can be reduced to 0.003 nm//spl deg/C. We model numerically a grating in a ridge optical waveguide with a polymer overlayer in order to optimize the design of the waveguide structure for low temperature sensitivity. The model simulates correctly the experimental dependence of the grating wavelength shift with temperature and it predicts that in an optimized waveguide design, the temperature dependence can be as low as 0.0006 nm//spl deg/C.