Fabrication of Bragg gratings in multilayer planar waveguide of chalcogenide glasses

Summary form only given. In recent years, the amorphous chalcogenide glasses (ChG) have attracted much interest for applications in linear and nonlinear integrated optical systems. High optical transparency in the 1-10 /spl mu/m wavelength region, large nonlinear refractive index, and low phonon energy of these materials make them very useful for infrared telecommunication network, nonlinear switching devices, and optical amplifiers. ChG also exhibit high photosensitivity when exposed to a suitable wavelength corresponding to band gap energy. As/sub 2/S/sub 3/ (E/sub g/=2.35 eV, /spl alpha//spl sim/10/sup 3/ cm/sup -1/) used as the cladding layer, has been shown to be more photosensitive than As/sub 24/S/sub 38/Se/sub 38/ (E/sub g/=2.10 eV, /spl alpha//spl sim/10/sup 4/ cm/sup -1/) when exposed at 514.5 nm, but the latter has a much higher nonlinear refractive index (n/sub 2//spl sim/1.75/spl middot/10/sup -14/ cm/sup 2//W). The multilayer waveguide geometry is used because of lower losses and higher coupling efficiency compared to a single layer waveguide. A photoinduced refractive index change in these materials is used to realize a variety of photoimprinted integrated optical components in planar lightwave circuits (PLC). In the present work, the fabrication of Bragg reflectors is demonstrated which can be used as wavelength selective elements for WDM networks, and nonlinear Bragg gratings (Bragg solitons) for nonlinear all optical switching devices.