Hysteresis of the output radiation power of cw AlGaAs heterolasers

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 P_cr 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 P_cr 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.