The influence of controllable amount water admixture (up to 0.5 w.%) in benzoic acid on the proton exchange process X-cut congruent lithium niobate was studied this paper by means mode spectroscopy, optical microscopy, profilometry, atomic force XRD, and chemical etching. It has been determined that addition w.% Н2О increases rate changes phase composition number defects exchanged layer niobate.

This study involves the results of research on short-term and long-term DC-drifts in electro-optical modulators based annealed proton exchange waveguides LiNbO3 crystals after wafer pre-annealing. The relaxation time DC-drift operating point for a drift is measured minutes, it hours days. was by applying bias voltage changing crystal temperature. obtained show significant impact stability EO-modulators treatment defective structure near-surface layer crystal. Treatment disturbed simultaneous...

Kinetics of phase transitions in the surface layer proton-exchanged planar waveguides on X-cut lithium niobate crystal during annealing at 330, 350, and 370°C was investigated by optical methods (dark field microscopy, crossed-polarizers bright mode spectroscopy). Nucleation growth stages transformations were identified. Based spectroscopy data analysis previous works, we assume that transformation κ2-phase into κ1-phase further α-phase observed experiment.

ABSTRACTSamples cleaning in ammonia-peroxide solution (APS) leads to increase of waveguides contrast after proton exchange comparing with the without APS cleaning. Surface and sublayer lithium niobate was studied by optical microscopy, scanning electron microscopy X-ray diffraction. It detected many multidirectional scratches on surface defective till a depth 6 μm. These facts are important for manufacture integrated circuits: repeatability, waveguide loss circuit drift parameters.

It is shown that for decreasing the surface roughness of ridge waveguides formed on –Z-cut LiNbO3 with wet etching it useful to carry out annealing sample Cr-mask layer prior etching. The reason in Cr-layer inheritance near-surface defects substrate and disclosure these during process. was confirmed by methods scanning electron, optical dark field bright microscopies initial annealed etched under different conditions.

Phase transitions during annealing of proton-exchanged (PE) layers in X-cut and Z-cut lithium niobate (LN) crystals were studied. The following sequence phase is proposed: β1, β2-phases → κ2-phase κ1-phase α-phase. Main feature transition LN the formation particles κ1-phase, which create a modulated structure. In case LN, do not arise PE-waveguide consists coherent until they completely transform into

The phase structure of planar and channel, un-annealed annealed proton exchanged waveguides made in benzoic acid + lithium benzoate melts on Z cut congruent niobate crystal was investigated using mode spectroscopy, IR XRD, SEM, AFM, microindentation, wet etching techniques. In waveguides, three layers (probably β2, β1, κ2 phases) can be distinguished. At least two different structural are present channel waveguides. Proton exchange (225oC, 28 h) 3 mol.% leads to formation a thin layer α phase.

Methods of chemical etching, non-contact profilometry, X-ray analysis and mode spectroscopy enabled to find out that proton exchange channel waveguides formed on Z cut lithium niobate crystal in the molten benzoic acid with addition 3 mol.% benzoate at temperature 225°C were composed κ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -phase a thin layer α-phase. Proton +Z -Z faces (with or without benzoate) occurs same rate.

The paper presents results of structure analysis silicon oxide films prepared by plasma enhanced chemical vapor deposition (PECVD) methods with a high power excitation. were deposited from hexamethyldisilazane and oxygen mixture. Dependences on parameters are presented.

It was established by chemical etching that proton exchange on the surface of LN +Z cut in molten benzoic acid at temperature 190°...210°C during 1...4 h causes fabrication channel waveguides, consisting 3 phases.

This work is devoted to the visualization and evolution of κ1-phase particles in annealed proton exchange (PE) waveguides. It well-known that presence optical waveguides leads an increase their losses instability operation. has been found precipitated propagate through whole waveguide depth have perpendicular orientation surface lithium niobate crystal. These results are important for fast quality control PE

This work involves results of research on short-term and long-term DC-drifts in electro-optical modulators based annealed proton exchange waveguides LiNbO3 crystals after wafer pre-annealing. The relaxation time the DC-drift operating point for a drift is minutes, drift, hours days. was measured by applying bias voltage changing crystal temperature. Obtained shows significant impact stability EO-modulators treatment defective structure near-surface layer crystal. Treatment disturbed twice...

Photoluminescence in Functionalized/Doped Graphene Quantum Dots: Role of Surface States It has been shown that functionalization/doping Dots (GQDs) can lead to further tuning their already existing band gap. We have successfully functionalized GQDs (synthesized by hydrothermal process) with oxygen, hydrogen, fluorine, and doped nitrogen using capacitively coupled plasma respective gas as evidenced Raman X-ray photo emission spectroscopy (XPS). Room temperature photoluminescence (PL) each GQD...

Feasibility of electrode-less sensor to measure the external electric field intensity is shown by forming on a single lithium niobate crystal, firstly, channel waveguides proton exchange with following annealing, and then - domain area specified topology in one arms interferometer.

The treatment of lithium niobate surface with argon plasma results in an increase defect density within the layer which affects process proton exchange causing formation proton-rich phases Li <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> H xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> NbO xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> solid solution (X cut), rise internal stress, and even local dissolution zones maximal...

Different methods (optical, laser, and electron microscopy) used to compare of the structural features near-surface layers single-crystal lithium niobate plates with a predetermined distribution impurities along its length from Crystal Technology (USA). Investigation optical characteristics (refractive index depth planar waveguide) was performed using method mode spectroscopy, also obtained were compared parameters sample Technology. It is shown that proton-exchange waveguides are very...

The influence of reverse proton exchange (RPE) and some types surface pretreatment (exposure to Piranha or RCA-1 solutions HNO3+HF mixture) on the structure properties proton-exchanged layers has been studied in X-cut lithium niobate (LN). It shown that rate phase transitions PE during RPE is greater than annealing at same temperature. Pretreatment LN before by slightly increases refractive index change Δne resulting waveguide, whereas mixture decreases it.

The present paper aims to investigate the structure and properties of near-surface layers optical materials modified by treatment in hydrogen plasma (H-plasma). For this quartz soda-lime glasses, lithium niobate (LN) as delivered LN after proton exchange were used. investigated IR spectroscopy, Raman X-ray diffraction analysis, atomic force microscopy, mode scanning electron wet chemical etching. During H-plasma penetrated into caused increasing number defects materials. Changes shape...

The paper presents results of FTIR analysis silicon organic thin films prepared by plasma enhanced chemical vapor deposition methods. were deposited from hexamethyldisilazane and oxygen mixture. Refractive index rates obtained. Dependencies on source power are presented. Possibility to prepare with variable properties during was demonstrated.

The paper proposes protective silicon-silicon oxide thin film for integrated optical circuits (IOC) based on lithium niobate. Threshold values silicon layer thickness were experimentally determined. Silicon-silicon layers deposited IOC samples with combination of DC unipolar pulsed magnetron sputtering, reactive and plasma enhanced chemical vapor deposition inductively coupled source (ICP-PECVD). Selection proper regimes allowed us to obtain films demonstrating no attenuation signal.

The effect of highly-ionized medium (plasma) with variable composition on the optical and structural properties proton exchanged planar waveguides in lithium niobate is described this paper. This was investigated by prism coupling method X-ray diffraction analysis. evolution treated plasma also studied after high temperature annealing. It determined that waveguide contrast (Δn) decreased depth increased, but there were no significant deformations near-surface region; other effects generated...

Microindentation of the proton exchange layers on X-cut lithium niobate crystal was performed. It has been found that causes an increase in "true" hardness and decrease elasticity.