S. Patela

CdS microcrystallites‐doped thin‐film glass waveguides

Thin films of Corning 7059, glass doped with CdS (2%–4% by weight) microcrystallites, with diameters presumably larger than 6 nm, were fabricated using rf sputtering technique. Sharp optical cutoff near 500 nm is visible on the absorption spectra of the films. Both Raman and absorption spectra presumably reveal the presence of size effects. At λ=632.8 nm the refractive index of the films varies from 1.55 to 1.69 depending on rf power. Propagation losses for TE0 guided mode are about 10 dB/cm.

Nonlinear optical properties of thin‐film waveguides deposited onto semiconductor‐doped glasses

We report the fabrication procedure and properties of optical nonlinear guided wave structures consisting of a thin film of Corning 7059 glass deposited on the surface of CdSxSe1−x doped glass. The limiting action in power‐dependent prism coupling in the structures produced is described. The nonlinear prism coupling is used to evaluate both the sign and the steady‐state value of the intensity‐dependent refractive index of the substrate. For the glass used the nonlinearity is negative and its value is in the range of 10−10 m2/W.

Nonlinear optical waveguides made of thin films of glass doped with semiconductor microcrystallites

The rf sputtering technique was used to deposit thin films of CdS microcrystallite-doped glass onto standard glass substrates. The presence of the microcrystallites in the films was verified by using Raman spectroscopy. A sharp cutoff below 500 nm was visible on the transmission spectra of the semiconductor microcrystallite-doped films. The evidence of size effects was visible on both Raman and transmission spectra of the films. Power-dependent prism coupling of light into the waveguides was investigated under cw-illumination conditions. The angular variation in decoupled power becomes more asymmetric with increasing input power until switching occurs on one side of the characteristic. The nonlinearity involved is presumably of thermal origin.

Some properties of r.f. planar magnetron-sputtered corning 7059 glass films

Abstract Low loss Corning 7059 waveguides have been produced by r.f. magnetron sputtering in an oxygen-argon mixture. The influence of the sputtering process parameters on the deposition rate, refractive index, optical losses and stoichiometry of the films is described. It is shown that, contrary to the results obtained with standard r.f. sputtering, the increase in oxygen partial pressure in the sputtering atmosphere causes a significant increase in the refractive index. The dependence of the birefringence of the films on the deposition conditions is also presented.

Power-transfer effects in monomode optical nonlinear waveguiding structures

We describe power-transfer effects, over a certain threshold, among constituents of planar waveguiding structures consisting of an optical linear layer deposited onto a nonlinear substrate (CdS(x)Se(1-x)-doped glass). Proper selection of the thickness of the linear waveguiding film and the refractive index of the linear cladding allows one to obtain optical transistor action and to construct all-optical AND, OR, NOT, and XOR logic gates. The effects appear for the TE(0) guided mode.

Nonlinear Guided Wave Structures Using Semiconductor Doped Glasses

The fabrication procedure and properties of optical nonlinear guided-wave structures are reported. The structures consist of a thin film of Corning 7059 glass deposited by RF planar magnetron sputtering on a surface of CdSxSe1-x doped glass. The coupling of light into the waveguides characterized by a power dependent propagation constant was studied. The experiments were performed at two wavelengths λ= 0.4880 μm and λ= 0.5145 μm with a laser working in cw and mode-locked regimes of operation. It is shown that integrated optical structures fabricated exhibit strong nonlinear effect with subnanosecond response time.

Thin Films Of Glasses Containing CdS Microcrystallites For Optical Nonlinear Devices

Two approaches to fabrication of optical nonlinear waveguides consisting of thin glass films doped with CdSxSe1_x and CdS microcrystallites, deposited onto standard glass substrates are described. The films were fabricated by RF planar magnetron sputtering in Ar atmosphere of two types of targets: a monocomponent one made of CdSxSe1_x microcrystallites-doped glass and a composite one consisting of an undoped glass plate and CdS powder. The Raman spectroscopy measurements revealed the presence of semiconductor microcrystallites only in the films fabricated with the composite target. Sharp optical cut-off near 500 nm is visible on the transmission spectra of these films. The films can be used as planar optical waveguides. The refractive index of these films at λ= 632.8 nm varies from 1.55 to 1.70 depending on RF power supplied to the sputtering system. Propagation losses for TEo mode at the same wavelength are about 10 dB/cm.

Interferoketric Measurements Of Nonl1Nearities In Planar Optical Waveguides Deposited On Cd(S, Se) Doped Glasses

A high light intensity is an inherent feature of integrated optics waveguides. A beam dimensions can be easily reduced hundred times or more, with the appropriate change in beam intensity. Integrated optic structures with high light intensities are particularly well suited for nonlinear optical experiments.