Near Stoichiometric MgO Doped Ti:Er:LiNbO3 Waveguides for Active Integrated Optical Devices

Active Ti:Er:LiNbO3waveguide devices have been realized using congruent LiNbO3substrates. However, serious photorefractive damage in the visible and near infrared wavelength regions limits the choice of pump wavelengths and the applications of these devices. In this project, a novel fabrication process realizing near-stoichiometric (NS) MgO doped Ti:Er:LiNbO3optical waveguides that exhibit low waveguide loss and low photorefractive damage susceptibility is proposed. Local erbium (Er3+) rare earth ions doping will be carried out first in congruent MgO doped LiNbO3crystals. Subsequently, vapour transport equilibration (VTE) treatment and indiffusion of titanium (Ti) metal will be carried out simultaneously, or VTE treatment will be carried out first followed by thermal indiffusion of the Ti metal. The surface morphologies, the structural and crystalline phases, the Li compositions, the photorefractive and the Er3+spectroscopic properties of the NS waveguides will be characterized. Based on the parameters obtained, the fabrication of high optical quality NS MgO doped Ti:Er:LiNbO3waveguides will be optimized. To demonstrate the applications of the NS waveguides, 980nm pumped waveguide amplifiers operating at the 1550nm telecommunication wavelength will be designed and fabricated. The performances of the amplifiers will be superior to existing reported devices due to the increased photorefractive damage threshold of the NS waveguides.