Temperature-Dependent Study on Modal Gain and Differential Gain of 1.3-$\mu$ m InAs–GaAs QD Lasers With Different $p$-Doping Levels

The modal gain and differential gain of 1.3-μm InAs-GaAs quantum-dot (QD) lasers with different doping concentrations have been investigated as a function of injection current under different operation temperatures from 20°C to 120°C. The results show that QD laser with light doping density can improve the characteristic temperature (T
_o
), modal gain, and differential gain and reduce the threshold current density.