In order to improve the thermal characteristics of single-chip semiconductor lasers and increase the output power of the device, a new type of vertical packaging structure of heat sink is proposed and analyzed. The heat sink retains the advantages of simplicity and being easy to apply, and the performance of heat dissipation has been improved obviously. The new heat sink structure is believed to be more suitable for packaging of the high-power semiconductor laser chips by heat conduction. Finite-element thermal analysis was used to simulate the thermal field distribution and thermal vector distribution in the conventional structure and the new structure. The simulation results show that the thermal resistance of the conventional structure is 2.0 K/W and the thermal resistance of the new heat sink is less than 1.6 K/W. The theoretical calculation results show that the output power of the packaged laser by new heat sinks can be significantly improved.
In this study, uniform InAs QDs were grown on the GaAs (001) substrate by MBE by the S-K mode. The effects of strain reducing layer and rapid thermal anneling on the optical properties of InAs/(In)GaAs QDs were investigated by PL measurements. The annealing results in PL peak energy red-shift which strongly depends on In composition of InxGaAs strained reducing layer , QDs with lower density and/or capped by an InGaAs layer are very sensitive to the annealing. At given annealing conditions, PL peak energy blue-shift of low-density QDs is much larger than that of high density QDs.
According to the principle of carrier diffusion within injection stripe, we fabricated a new type of high power single
quantum well broad area semiconductor laser. The designed device has a special current injection stripe which results in
a Gaussian-like photon gain laterally. The output power is up to 3.75 watt when the beam quality factor M<sup>2</sup> is 10.6 in
continuous-wave operation, and the beam quality factor M<sup>2</sup> is 5.4 when the output power is 2.5 watt at the same
operation condition. The beam quality of broad area semiconductor single quantum well laser has been improved obviously by the designed device
Semiconductor lasers at wavelengths around 1.3μm are widely used for optic communications. For GaInNAs, the
incorporation of nitrogen in the active layer can reduce the band-gap energy and allow emission wavelengths as long as
1.3μm. Ridge waveguide GaInNAs strain single-quantum-well lasers were fabricated with pulsed anodic oxidation
(PAO). Using the technology PAO, we prevented the damage from the ion bombardment in the procedure of sputtering
silicon dioxide used for building the insulating film. The output power of the laser with a wavelength of 1.31μm reached
14mW in CW mode at room temperature. The threshold-current was 18mA and its density was 360A/cm<sup>2</sup>. The
characteristic temperature of lasers was 135.1K and the quantum efficiency reached 76%.