Abstract

Lithium niobate waveguide electrooptic devices have exhibited state-of-the-art performance in experimental lightwave systems [1]. Of paramount importance for their introduction into field system use is their operational stability and immunity to environmental changes. To date, a number of phenomena affecting the stability of Ti:LiNbO₃ devices have been identified, including pyroelectric biasing [2], photorefractive damage [3], buffer layer drift [4], and humidity sensitivity[5]. Here we have quantified the stability of a class of Ti:LiNbO₃ external modulators by long-term measurements of bit-error-rate (BER) performance in a 1 Gb/s optical transmission system. We found that long-term changes of the optical bias point caused no more than 0.6 dBO power penalty variation and that this penalty could be prevented through automatic feedback control.

© 1988 Optical Society of America