Analysis of the room temperature performance of 1.3-1.52 μm GaInNAs/GaAs LDs grown by MBE

Abstract

Lasing emission is demonstrated at room temperature in the entire spectral region from 1.29 to 1.52 microns using GaInNAs/GaAs quantum well (QW) laser diodes (LD) grown by molecular beam epitaxy on GaAs substrates. The separate confinement heterostructures (SCH) is made up by AlGaAs cladding layers, a GaInNAs-based QW and GaAs barriers. To achieve lasing emission from 1.29 to 1.52 microns the In in the QW content is maintained at 40%, while the N content is varied from 1.3 to 3.3%. With this structure, the threshold current density (Jth) and external differential quantum efficiency (hd) at 1.29 microns are 685 A/cm² and 45 %, respectively. Increasing the wavelength to reach 1.5 micron emission degrades these figures to Jth=2890 A/cm² and hd=23% at 1.49 microns, and to Jth=4060 A/cm² and hd=16% at 1.52 microns, which still represent a very large improvement with respect to previous reports of LDs based on the quaternary. Even though adding N to the structure decreases the internal quantum efficiency (hi), from 75% to 50%, this figure does not change with increasing wavelengths up to 1.44 microns. The differential modal gain also degrades as a result of adding N to the QW, but like the case of hi, does not change significantly with increasing wavelength. Thus, achieving long wavelength emission up to 1.55 micron emission starts to become viable, even with simple LD structures.