Strain‐induced degradation of GaAs injection lasers

This letter shows that strain is a controlling factor in the rapid degradation of GaAs double‐heterostructure junction lasers. A birefringence study of these lasers reveals extensive strain fields introduced during the bonding procedure resulting from the different thermal‐expansion coefficients of the materials involved. A new bonding procedure was developed which does not introduce significant strains. Lasers fabricated with the old and new bonding procedures were subjectively categorized as low, moderate, or high strained. A direct correlation was measured between low‐strain and room‐temperature cw laser lifetime. Lasers fabricated with the new bonding procedure have operated cw for as long as 880 h.