Reliability estimation from zero-failure LiNbO/sub 3/ modulator bias drift data

Since x-cut LiNbO/sub 3/ (LN) optical modulators exhibit bias drift that rolls over around a voltage limit of most systems, their laboratory aging tests sometimes yield zero-failures and do not generate sufficient estimates of device reliability. In this regard, a modified calculation method is proposed and applied to data of OC192 x-cut LN modulators. The calculation presumes a time-independent probability that modulators are expected to have a voltage peak higher than the failure criterion. The obtained small failure rate is considered to be consistent with a rolling-over type drift behavior of these modulators.