Chalcogenide coatings of Ge15Sb20S65 and Te20As30Se50

Chalcogenide coatings are investigated to obtain either optical components for spectral applications or optochemical sensors in the mid-infrared. The deposition of Ge(15)Sb(20)S(65) and Te(20)As(30)Se(50) chalcogenide glasses is performed by two physical techniques: electron-beam and pulsed-laser deposition. The quality of the film is analyzed by scanning electron microscopy, atomic force microscopy, and energy dispersive spectroscopy to characterize the morphology, topography, and chemical composition. The optical properties and optical constants are also determined. A CF(4) dry etching is performed on these films to obtain a channeled optical waveguide. For a passband filter made by electron-beam deposition, cryolite as a low-refractive-index material and chalcogenide glasses as high-refractive-index materials are used to favor a large refractive-index contrast. A shift of a centered wavelength of a photosensitive passband filter is controlled by illumination time.     

Erbium-Ion-Doped Tellurite Glasss Fibers and Waveguides — Devices and Future Prospective: PART I

This review article focuses on the suitability of Er³⁺-doped tellurium oxide glass for optical amplification in fiber, waveguides and as a component for optical integration to meet the emerging demand for broadband and fiber-to-home networks. The importance of the glass structure, in the context of Er³⁺-ion spectroscopy, is emphasized for dissolving large concentrations of dopant ions. The spectroscopic methodologies involved in maximizing the gain per unit length of Er³⁺-doped fiber is explained. In Part II of this study, a review of how the fiber gain data was then employed to engineer amplification in waveguides, which can be integrated with semiconductor pump sources, is presented.     

The radiation mode theory in ultrasonics

This paper describes the history and the state of the art in radiation mode theory (RMT) in ultrasonics. The RMT originates from electromagnetism in which it has proved to be very efficient in the field of wave guides and discontinuities. In ultrasonics, the RMT made its entrance only a decade ago and has already proved to be very efficient in describing the interaction of sound with discontinuities such as a step on a plate, a liquid wedge, the extremity of a plate and much more. It is likely that the development of the RMT for two-dimensional (2-D) isotropic media has come almost to an end. This paper lists the results obtained so far. Further extensions to more complicated media are to be expected in the coming decade.