‘‘Thermal fixing’’ of Ti-indiffused LiNbO3 channel waveguides for reduced photorefractive susceptibility

A ‘‘thermal fixing’’ process that dramatically reduces the photorefractive susceptibility of Ti-indiffused LiNbO3 channel waveguides has been demonstrated. Guided-wave Mach–Zehnder interferometric modulators were used to characterize the photorefractive susceptibility of the waveguides. These devices were evaluated before and after the thermal fixing process which was seen to be erasable, reproducible, and long-lived. Photorefractive effects were reduced ten times for waveguide operation at λ=0.46 μm and more than 100 times for operation at λ=0.85 μm.