1. The threshold current density for a stripe geometry AlGaAs laser is 3500 A/cm'at 15 °C. Determine the threshold current at 60°C when the threshold temperature coefficient for the device is 180 K and the contact stripe is 20x100 pm.

2. The coated mirror reflectivity at either end of a 350 um optical cavity of an injection laser is 0.5 and 0.7. At the normal operating temperature of 300 K the threshold current density for the device is 2 kA/cm and the gain factor is 22x10 cm/A. Determine the loss coefficient of the optical cavity.