Investigation of GaAs-Based Laser Diode Adopting an Al Composition Gradient Double Waveguide Structure and its Photoelectric Properties

The double waveguide structure of a 1060 nm laser diode with different Al composition linear gradient was designed for achieving high output power. In contrast to the single waveguide layer with Al-free composition gradient structure, the double waveguide layer with a reverse Al composition gradient from n side to p side showed excellent optoelectronic properties. We found that the reverse Al composition gradient double waveguide layer could decrease injection potential barrier for electrons and holes, as well as has a high block leakage potential barrier, which can be help to increase carrier transport and optical confined factor. Meanwhile, it can improve sheet carrier concentration in order to decrease non-radiative recombination. When the injection current is 6 A, the maximal output power and peak wall-plug conversion efficiency are 6.12 W and 81.1%, respectively. The influencing mechanism of these photoelectric parameters on power and wall-plug conversion efficiency was discussed. The novel waveguide structure will be favorable for designing epitaxial structure and providing a theoretical basis for high-power laser diode.