Abstract

Electrooptic waveguide modulators based on Ti-indiffusion into the LiNbO₃ have been demonstrated to perform many important functions. However, the photorefractive effect along with other causes of drift must be eliminated or compensated to provide the long term stability needed in a communication system. The photorefractive effect is associated with the photo-excitation of the Fe²⁺ impurities.¹ In Ti-indiffused waveguide devices the carriers drift toward the electrodes and affect the light propagation via the electrooptic effect.² By going to the infrared the photons can no longer excite the Fe²⁺ ions. Therefore, the photorefractive effect is greatly reduced. However, it is never entirely eliminated, presumably, there are still some other channels to provide the charge separation.

© 1982 Optical Society of America