OPTICAL-DAMAGE RESISTANCE OF LITHIUM-NIOBATE WAVEGUIDES

The optical damage resistance of diffused lithium niobate waveguides is discussed. Long-term laser power handling performance is assessed by recording the spatial intensity changes occuring as a function of time in a waveguide's far field. Out-diffused waveguides are found to offer greater long-term resistance to optical power losses caused by optical damage than do waveguides formed by either ion exchange or titanium in-diffusion. Any waveguide's resistance to optical damage is lowered by inadvertent exposure to chemical reducing conditions that can prevail during device fabrication. Waveguides exposed to the severe chemical reducing conditions are found to exhibit nonlinear behavior when exposed to high laser powers and short laser wavelengths.