Optical anisotropy of InAs quantum dots and quantum dashes on InP

Elongated InAs quantum dashes on InP introduce polarization anisotropy that limits polarization-insensitive photonic devices. We evaluate InAs quantum dots grown using a GaAs insertion layer that suppresses dash formation. Room-temperature polarization-resolved photoluminescence shows that the degree of linear polarization (DoLP) decreases from 0.3227 ± 0.0052 for a dash-dominant reference to 0.0382 ± 0.0029 for a dot-dominant sample. Broad-area lasers fabricated from eight stacked dot layers show no statistically significant threshold-current dependence on cavity orientation over 600–1200 µm cavities. These results indicate optically near-isotropic InAs quantum dots on InP grown using the GaAs insertion layer.