The reliability of (AlGa)As CW laser diodes

This paper reviews the major factors bearing on the reliability of (AlGa)As CW laser diodes. The degradation modes of facet mirror damage, contact degradation, and internal damage are discussed in terms of our present knowledge of their effects on device performance, their origin, and their reduction or elimination. Detailed results are presented for oxide-defined stripe-contact lasers and, although reliability results are a strong function of fabrication technology, there are many issues common to all fabrication technologies, and these are emphasized. Lasers have been operated in our laboratory for more than 40 000 h with extrapolations indicating a median time to failure (MTTF) between 10⁵and 10⁶h. In these lasers both facet damage and contact degradation appear to be under control and internal damage remains the dominant failure mechanism. While still not well documented, for internal damage a so called "activation energy" of 0.7 eV may be useful for high temperature accelerated lifetests. Most of the reliability data deals with threshold current increase, however, shifts in far-field pattern and changes in laser modulation characteristics, such as self-sustained oscillations, may affect laser performance in real systems.