Pulsations and absorbing defects in (Al,Ga)As injection lasers

Forty-seven strip-buried-heterostructure (Al,Ga)As lasers have been examined for pulsations and absorbing defects in the active volume. All 18 pulsating lasers were found to have defects while only one of the 29 nonpulsating lasers had a visible defect. These results show conclusively that absorbing defects can cause pulsations in double-heterostructure injection lasers and support a recently published model for the origin of these pulsations. The presence of absorbing defects and pulsations also correlates with structure in the functional dependence of −I2 d2V/dI2 upon I above threshold. Lasers not exhibiting pulsations were aged, and the same correlation was found between the development of defects (particularly mirror darkening), the change in −I d2V/dI2, and the development of pulsations.