Quantum dot photonics: Edge emitter, amplifier and VCSEL

Low transparency current density and improved temperature stability with a large characteristic temperature T0 > 650 K up to 80 °C are demonstrated for 1.3 m MBE grown InGaAs quantum dot (QD) edge emitting lasers. Digital modulation with an open eye pattern up to 12 Gb/s at room temperature and bit error rate below 10-12 for 10 Gb/s modulation was realized for this wavelength. Semiconductor optical amplifiers based on InGaAs QD gain media achieved a chip gain of 26 dB. A conventionally doped semiconductor DBR QD-VCSEL containing 17 p-modulation doped QD layers demonstrated a cw output power of 1.8 mW and a differential efficiency of 20 % at 20 °C. The maximum -3dB modulation bandwidth at 25 °C was 3 GHz. First MOCVD-grown QD-VCSELs with selectively oxidized DBRs and 9 QD-layers were realized, emitting at 1.1 m. A cw multimode output power of 1.5 mW, 6 mW in pulsed operation, and an cw external efficiency of 45 % were achieved at 20 °C. The minimum threshold current o f a device with 2 m aperture was 85 A.