Surface-related reduction of photoluminescence in GaAs quantum wires and its recovery by new passivation

Etched GaAs quantum wires (QWRs) and selectively grown (SG) QWRs were fabricated, and dependence of their photoluminescence (PL) properties on QWR width (W) and QWR distance to surface (d) were investigated. PL intensity greatly reduced with reduction of W and d, due to non-radiative recombination through surface states. Surface passivation by growing a Si interface control layer (Si-ICL) on group III-terminated surfaces greatly improved PL properties

Al2O3 Insulated-Gate Structure for AlGaN/GaN Heterostructure Field Effect Transistors Having Thin AlGaN Barrier Layers

An Al2O3 insulated-gate (IG) structure was utilized for controlling the surface potential and suppressing the gate leakage in Al0.2Ga0.8N/GaN heterostructure field effect transistors (HFETs) having thin AlGaN barrier layers (less than 10 nm). In comparison with Schottky-gate devices, the Al2O3 IG device showed successful gate control of drain current up to VGS= +4 V without leakage problems. The threshold voltage in the Al2O3 IG HFET was about -0.3 V, resulting in the quasi-normally-off mode operation

Observation of dynamics in a 5 Ghz passively mode-locked InAs/InP (100) quantum dot ring laser at 1.5 µm

In this paper we present the first observation of passive mode-locking in a quantum dot (QD) ring laser operating at wavelengths around 1.5 mum. The InAs/InP QD laser structure is grown on n-type (100) InP substrates by metal-organic vapor-phase epitaxy

Observation of Q-switching and mode-locking in two-section InAs/InP (100) quantum dod lasers around 1.55 μm

For the first time passive mode-locking in two-section quantum-dot lasers operating at wavelengths around 1.55 µm is reported. Pulse generation at 4.6 GHz from a 9-mm long device is verified by background-free autocorrelation, RF-spectra and real-time oscilloscope traces. The output pulses have a 7 nm optical bandwidth and are stretched in time and heavily up-chirped with a value of 20 ps/nm. From a 7 mm long device Q-switching is observed over a large operating regime. The lasers have been realized using a fabrication technology that is compatible with further photonic integration, and can perform the function of e.g. a mode-comb generator

Non-inverted multiple wavelength converter at 40 Gbit/s using 1550 nm quantum dot SOA

Error-free and low penalty

Lasing of wavelength-tunable (1.55µm region) InAs/InGaAsP/InP (100) quantum dots grown by metal organic vapor-phase epitaxy

The authors report lasing of InAs/InGaAsP/InP (100) quantum dots (QDs) wavelength tuned into the 1.55 µm telecom region. Wavelength control of the InAs QDs in an InGaAsP/InP waveguide is based on the suppression of As/P exchange through ultrathin GaAs interlayers. The narrow ridge-waveguide QD lasers operate in continuous wave mode at room temperature on the QD ground state transition. The low threshold current density of 580 A/cm2 and low transparency current density of 6 A/cm2 per QD layer, measured in pulsed mode, are accompanied by low loss and high gain with an 80-nm-wide gain spectrum