Index modulation Bragg gratings directly imprinted on sol gel layers

Among the fabrication techniques of integrated optical devices, the sol-gel chemistry is now performant enough to make thin films of transparent materials with controlled purity and composition, at low temperature. Semi-mineral semi-organic solutions allow dip coating followed by low temperature baking to deposit vitreous films up to eight micrometers thick which are free from cracks. A local polymerization process through UV exposure enables hybrid components compatible with electronic planar silicon or III- V components. This UV imprinting method is used here to make index modulation gratings with use of a holographic equipment as an alternative to the use of a costly phase mask. Gratings have been imprinted on various sol-gel films; single layer, with a protective coating, and/or with an isolating buffer layer from the substrate, which is silicon and glass. Diffraction magnitude is measured in the various cases, as well as analysis and computer simulations are performed. Wavelength filters are experimented and studied. This shows the potential of this low cost technology in integrated optics, for application in telecommunications.