Low threshold current density of InAs quantum dash laser on InP (100) through optimizing double cap technique

We report on the uniformity improvement of InAs quantum dashes (QDHs) grown by molecular beam epitaxy on InP (100) through optimizing double cap technique. Broad-area lasers were fabricated with an emission wavelength of 1.58 μm. A threshold current density of 360 A/ cm2 was achieved for a five stack QDH structure and a cavity length of 1.2 mm. This results from a reduced inhomogeneous broadening (62 meV) and lower internal optical losses (7 cm ^-1). The achievement paves the way toward ultralow threshold semiconductor laser for telecommunications.