Direct electron beam writing of optical devices on Ge-doped flame hydrolysis deposited silica

Electron beam irradiation of silica is a very flexible technique for the fabrication and trimming of optical circuits for the telecommunications and biosensing areas. In this paper, we review the effects induced by electron beam irradiation of germanium-doped, flame-hydrolysis deposited (FHD) silica. The structural modifications were studied with Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The compaction of the material was characterized by profilometry and the refractive index variation and index distribution of channel waveguides were characterized using the m-line technique and microreflectivity, respectively. Finally, some optical devices were fabricated using this technique with application in optical fluorescence sensing. The technique appears as a very interesting way of fabrication low-loss optical waveguides in silica.