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 QD-edge emitters. Digital modulation with an open eye pattern up to 12 Gb/s at room temperature and bit error rate below 10-12 for a 10 Gb/s modulation was realized for this wavelength. Semiconductor optical amplifiers based on InGaAs QDs achieved a chip gain of 28 dB. Conventionally doped semiconductor DBR QD-VCSEL containing 17 p-modulation doped QD layers demonstrated a CW output power of 1.7 mW and differential efficiency of 20 % at 20 °C. First MOCVD grown QD-VCSEL with selectively oxidized DBRs and 9 QD-layers were realized, emission was at 1.1 m. A CW multimode output power of 1.5 mW and external efficiency of 45 % was achieved at 20 °C. The minimum threshold current from a device with 2 urn aperture was 85 A.