THE PHOTOREFRACTIVE EFFECT IN TITANIUM INDIFFUSED LITHIUM-NIOBATE OPTICAL DIRECTIONAL-COUPLERS AT 1.3 MU-M

In titanium-indiffused lithium niobate directional couplers, photorefractive damage is seen at 1. 3 mu m when power levels in the guide exceed 25 mW (5 multiplied by 10**4 W/cm**2 ) with time constants on the order of 100 h. Damage is not observed at lower power levels. Using a theoretical model based on the coupled wave equations and extrapolating the high power results, no significant degradation in performance is predicted for devices with less than 5 mW coupled into the waveguide.