Temperature Characteristics of Gain Profiles in 1.3- $\mu\hbox {m} p$ -Doped and Undoped InAs/GaAs Quantum-Dot Lasers

The modal gain and differential gain of 1.3-mum p-doped and undoped InAs/GaAs quantum-dot (QD) lasers have been investigated as a function of injection current under different operation temperatures. The results show that p-doping improves the modal and differential gains in QD lasers at high temperatures. Exponential decrease in the differential gain profiles were observed in both types of lasers from 20degC to 80degC. Theoretical calculations based on the rate equation model for the undoped QD laser gain at different temperatures are presented.