Chiara Meneghini

Fabrication and characterization of integrated optical waveguides in sulfide chalcogenide glasses

This paper reports on the fabrication process of As-S-(Se)-based chalcogenide glass optical waveguides using three techniques: photolithography, laser beam writing, and ion implantation. The fabrication method of the bulk sulfide glasses and the processing of integrated devices are described and assessed in light of the propagation characteristics and optical losses in each case.

As 2 S 3 photosensitivity by two-photon absorption: holographic gratings and self-written channel waveguides

We observed two-photon-induced refractive-index changes in As2S3 by exposure in the 800-nm region. We studied this photosensitivity by writing interference gratings on a 2-μm As2S3 thin film. This property is the key to creating self-written channel waveguides in a planar As2S3 slab.

Luminescence from neodymium-ion-implanted As 2 S 3 waveguides

The luminescence of a neodymium-doped arsenic trisulfide planar waveguide at 1083 nm is reported. The dopant was introduced into the chalcogenide glass by ion implantation. The dopant distribution following ion implantation was predicted by molecular dynamic simulation and measured by Rutherford backscattering spectrometry. The most efficient pump wavelength was determined to be 818 nm. This observation of luminescence from rare-earth-ion implantation into chalcogenide glass, for the first time to the authors’ knowledge, suggests that this technique can be useful for rare-earth-doped devices.

Structural characterization of chalcogenide planar waveguide materials using near-infrared Raman spectroscopy

Chalcogenide glasses (ChG) based on As, S and Se are transparent in the infrared and have found applications in bulk, planar and fiber waveguide optical components. Due to their recent use in planar channel waveguide devices, a study to assess how structural variations imposed by processing conditions (film deposition) lead to changes in linear and nonlinear optical properties, is ongoing in our group. High resolution, near infrared (NIR) ((lambda) equals 840 nm) Raman spectroscopy has been employed to characterize changes in bonding between bulk glass specimens and glass in planar form. To obtain spectroscopic and spatially resolved information on chemical bonding, a microscope attachment has been constructed and is characterized as to its spatial resolution. Measurements are presented on single layer films prepared using processing and illumination conditions such as those used in fabricating waveguide components. These data are discussed in comparison to spectra obtained on bulk glass materials.

Ion implantation: an efficient method for doping or fabricating channel chalcogenide glass waveguides

In this paper we present two different applications of ion implantation in chalcogenide glasses: rare earth doping and channel waveguide fabrication. The luminescence of a neodymium-implanted arsenic tri-sulfide waveguide at 1083 nm is reported. The most efficient pump wavelength is determined to be 818 nm. The dopant distribution following ion implantation is predicted by molecular dynamic simulation and measured by Rutherford Backscattering Spectrometry. This observation of luminescence from rare- earth ion implantation into chalcogenide glass suggest that this technique can be useful for rare-earth doped devices. A study of neodymium luminescence peak power as a function of dopant concentration is reported. The second application of ion implantation is in the fabrication of channel waveguides by helium implantation.

Self-writing of a channel waveguide in As/sub 2/S/sub 3/: experiment and model

Summary form only given. We have recently shown the self-writing of a channel waveguide in a As/sub 2/S/sub 3/ slab waveguide by two-photon absorption (2PA). We observed that As/sub 2/S/sub 3/ is photosensitive by two-photon absorption in the 800 nm wavelength range, where the penetration depth is up to 2 cm. This combination is the key to induce the self-writing of a channel waveguide. A low intensity Gaussian beam incident into a planar waveguide is initially diffracted. When the intensity is high and the exposure long, the refractive index is increased along the central axis. The beam thus creates a channel and further increases the refractive index along this channel. A permanent channel waveguide is thus self-written.

Two-photon induced photodarkening in As 2 S 3 for gratings and self-written channel waveguides

Arsenic chalcogenides glasses are known to be photosensitive materials, showing photodarkening when illuminated with bandgap light (~500nm, ~2.4 eV)1.