The degradation behavior and the reliability of 980 nm lasers and 1480 nm lasers are reviewed and discussed. In addition, packaging problems for the high power lasers are also discussed from the application viewpoint. For 980 nm lasers the reliability in laser chip is limited mainly by the instability of an interface between the laser material (facet) and the anti-reflecting coating film, and for most 1480 nm lasers the reliability of the laser chip is determined mainly by the instability of a buried heterointerface. These reliability problems have been solved, however, by examining the material properties and improving device fabrication technology. The main packaging problem is a packaging-induced failure (PIF) causing sudden failure in 980 nm lasers sealed in dry N2 or Ar, but packaging problems have also been suppressed or eliminated. The device technology and packaging technology needed to make high power pump laser modules have been established, and erbium-doped fiber amplifiers pumped by these lasers are indispensable components of many optical transmission systems.
