Bistability of threshold in quantum dash-in-a-well lasers

The authors observe a bistability of threshold in a quantum dash ridge-waveguide laser diode at temperatures below 230 K. A giant and sometimes negative characteristic temperature, T₀, is measured at temperatures between 230 K and 320 K. They analyse the temperature dependent light-current characteristics of this device, and a similar device with lower barriers, to gain an insight into the mechanism causing bistable behaviour. A rate equation model shows localisation and passive saturable absorption as the causes of the bistable behaviour in the higher barrier laser at low temperature. They find good qualitative agreement between the experimental and the theoretical results.