Abstract:
An investigation was made of cw stripe (contact width 10 μ) planar heterojunction lasers. In a certain temperature range a hysteresis of the output power was observed under conditions corresponding to a smooth nonlinear watt-ampere characteristic. The hysteresis loop was due to abrupt changes in the output power at the ends of a certain range of currents and continuous changes in the power within this range, amounting sometimes to 50–80 mA. The dimensions of the loop and the critical power Pcr at which it changed suddently were functions of temperature: increase in temperature resulted in contraction of the loop and its conversion to the usual smooth inflection of the watt-ampere characteristic. The value of Pcr was estimated theoretically using a model of self-focused instability and was found to be approximately 10 mW at room temperature, in satisfactory agreement with the experimental results.