Stress-dependent behavior of InGaAsP semiconductor diode lasers.

Unmounted InGaAsP laser chips were placed across two diamond supports, and stress was applied with a probe that has a uniform cross section along the axis of the laser cavity. The laser was operated with short current pulses and a low-duty cycle to avoid effects due to the thermal impedance between the laser and its supports. Using this arrangement, compressive and tensile stresses within the active region were produced and studied in the same chip by placing the laser either p-side up or down. The techniques were used in stripe-geometry double-heterostructure lasers and planar buried heterostructure lasers, and the effects of current and thermal stress within these structures were related to fabrication-induced stress.