Bias stability of OC48 x-cut lithium-niobate optical modulators: four years of biased aging test results

Long-term 100(degree)C and 85(degree)C biased aging tests on OC48 x-cut lithium-niobate optical intensity modulators have been run for four years. The 100(degree)C test results clearly show that the bias voltage does not exhibit the conventional catastrophic growth curve, but rather peaks between 10 000 and 35 000 h at levels well below typically used bias voltage rails (+12 V). This promises a very high reliability for these x-cut lithium-niobate modulators for long-term bias-drift failure mode. Using the data, a bias-drift failure rate under ordinary operation conditions, 20 years at 40(degree)C, is estimated to be <1 failures in time with activation energy of 1.2 eV.