Reliability of semiconductor lasers for undersea optical transmission systems

The reliability of laser diodes developed for undersea optical transmission systems is analyzed. Up to 1000 device samples of two types (DC-PBH and VSB) are used. An aging test with constant light power operation of 5 mW is carried out at 10, 50, and 70°C for 10 000 h. The median lifetime at 10°C is conservatively estimated to be 1.6 × 10⁶hours. Failure rate at 10°C is estimated at 250 FIT´s at 25 years of service for the wear-out failure mode and at less than 50 FIT´s for the random failure mode with a sufficient margin. Furthermore, it is determined that reliability can be further improved by selection of long-life lasers through an additional third step screening aging.