Reliability of nonhermetic bias-free LiNbO3 modulators

Reliability for nonhermetic bias-free LiNbO₃ optical modulators is estimated from aging data in both dry and damp heat conditions. The two dominant failure modes for these devices are: 1) device performance degradation due to temperature-activated drift of the annealed proton-exchange waveguide; and 2) optical insertion loss increase due to humidity-induced deterioration of glued fiber joints. A total failure rate of 30 failures in time (FITs) is predicted for 20 years operation at 45°C and moderate humidity conditions (40% RH). This estimate based on laboratory-test data is consistent with a field failure rate <5 FITs observed in fielded devices.