Temperature-dependent lifetests of IRW lasers operating at 1.3 ¿¿m

For long-haul optical communications systems, the inverted rib waveguide (IRW) laser and its associated bonding technologies were chosen to give the highest possible reliability. Extensive lifetest studies have led to an endurance screen for wafers within 1500 hours to select wafers for further processing. Lifetests at 20, 50 and 150¿¿C have shown an apparent activation energy of 0.25 eV for passed wafers and 0.51 eV for reject wafers. Passed wafers give a median change of threshold current in 25 years of 7% at 50¿¿C, based on extrapolations of lifetest data from 1000 to 15 000 hours. The results support the view that the intrinsic degradation of good quality GalnAsP lasers occurs at an extremely low rate with low activation energy. More rapidly failing wafers suffer from an additional faster degradation mechanism which has a higher activation energy.