Internal loss in diode lasers with quantum well-dots

The internal loss at the lasing threshold were studied experimentally and numerically in laser cavities comprising dense arrays of InGaAs/GaAs quantum dots (quantum well-dots) as a function of the number of their planes and the output loss. Numerical values of the parameters were found that determine the free-carrier absorption in the active region and in the waveguiding layer. The optimal design of the laser diode was determined to achieve the highest external differential efficiency.