α-factor improvements in high-speed p -doped In 0.35 Ga 0.65 As/GaAs MQW lasers

The authors investigate experimentally for the first time the improvements in the linewidth enhancement factor, α, resulting from simultaneous addition of strain and p-doping in high-speed GaAs-based multiquantum well lasers. The α factor is determined from measured changes in both gain and refractive index as a function of CW bias current, yielding α 3.1 and 1.4 at the threshold lasing wavelength for unstrained GaAs/Al0.25Ga0.75As and p-doped strained In0.35Ga0.65As/GaAs devices, respectively.