Abstract
The purpose of this work was to develop a design methodology for the fabrication of waveguides in LiNbO3 operating in the single-mode regime at several wavelengths, with specific characteristics required to optimize integrated devices. To achieve this, it is necessary to obtain the relations between the optical characteristics of the waveguides and their respective fabrication conditions, and to introduce models of the waveguide formation process. The relations between fabrication conditions and optical characteristics of planar waveguides realized by titanium in-diffusion are documented extensively in the literature. However, reports on the characterization of waveguide fabrication processes, performed in a systematic way, could not be found, resulting in the need to combine information from several sources. Discrepancies among results from different researches are evident, resulting from different experimental methodologies and calibrations of equipment. Therefore, aiming at extracting a consistent data set, optical characterization techniques for the refractive index profile were employed to study series of samples.

Abstract

Abstract

Abstract
A method to fabricate chromium-doped lithium niobate substrates in which the active ions are introduced by thermal diffusion from a film is reported. Chromium concentration depth profiles have been obtained by secondary-ion-mass spectrometry and the relevant diffusion parameters have been derived. Fluorescence spectrum and upper laser level lifetime of chromium diffused proton-exchanged and chromium/titanium-diffused lithium niobate waveguides have been measured. A simple model has been used to estimate the performance of such structures as waveguide optical amplifiers and lasers. (C) 1995 American Institute of Physics.

Abstract
We report what is to our knowledge the first laser operation of Nd3+-doped LiNbO3 near 900 nm. An absorbed power threshold of 26 mW was obtained when the device was pumped at 814 nm. The design of the waveguide geometry to favor laser operation at this wavelength is demonstrated. (C) 1997 Optical Society of America.

Abstract
Relations between fabrication conditions and optical characteristics of planar waveguides made by proton exchange in benzoic acid are documented in the literature, but reports on the characterization of waveguide fabrication processes, performed in a systematic way, could not be found, resulting in the need to combine data from several authors. Discrepancies among results from different researches are evident, resulting from different experimental methodologies and calibration of equipment. Therefore, aiming at extracting a consistent data set, optical characterization of the refractive index profile was employed to study series of samples. The objective was to develop a methodology for fabrication of proton-exchanged channel waveguides in LiNbO3 operating in the single-mode regime at several wavelengths, with specific characteristics required to optimize integrated devices. To achieve this, it is necessary to obtain the relations between the optical characteristics of the waveguides and their fabrication conditions, and to introduce models of the waveguide formation process. (c) 2007 Society of Photo-Optical Instrumentation Engineers.