Thermal stabilities of strong UV written gratings in sol-gel germanosilicate planar waveguides.

Bragg gratings inscriptions or UV direct patterning of single mode channel waveguides are key issues for the achievement of new integrated components. Photosensitivity was reported in planar waveguides elaborated by different processes: FHD [1], PECVD [2], sol-gel [3], ion implantation [4], sputtering [5]. The sol-gel approach allows to prepare planar waveguides at low cost and low temperature. Hence, this process can be easily applied to industrial procedure. Photoinduced refractive index of 3 10-5 was already reported in H2 loaded sol-gel germanosilicate waveguides using the 488nm of an argon ion laser [3]. Recently, UV light imprinted Bragg grating with 97% reflectivity was imprinted in an hybrid sol-gel silica glass waveguide on silicon [6].