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Quantum dot infrared photodetectors (QDIPs) are receiving attention as next generation infrared photodetectors that offer high‐sensitivity and high‐temperature operation. The realisation of QDIPs on silicon (Si) substrates offer further great advantages in terms of cost reduction and higher‐resolution focal plane arrays. Indium arsenide/gallium arsenide QDIPs grown directly on on‐axis Si (100) substrates are demonstrated. These are expected to further reduce fabrication costs by utilising both the monolithic integration of QDIPs with Si readout integrated circuits and also the bare substrate cost (compared with offcut Si substrates). In the device, the peak detectivity at a temperature of 32 K is measured to be 5.8 × 107 cm Hz1/2/W of 6.2 μm at a bias 0.6 V, with a corresponding responsivity of 27 mA/W. This result indicates that QD structures directly grown on on‐axis Si substrates are very promising for the realisation of high‐performance QDIPs with low fabrication cost. [ABSTRACT FROM AUTHOR]

InGaAlP-based red vertical-cavity surface-emitting lasers (VCSELs) have been successfully fabricated using the proton-implanted planar structure suitable for mass production. A low threshold current of 2.5 mA with 666-nm lasing wavelength at room temperature and a high maximum continuous wave (CW) lasing temperature of 60°C have been achieved. In addition, it was found that the maximum CW lasing temperature decreased linearly with the increase in the device diameter. This was because the thermal resistance of the device was approximately inversely proportional to the device diameter [ABSTRACT FROM PUBLISHER]

660-nm-band InGaAlP Zn-diffused window structure lasers have been fabricated using highly Zn-doped GaAs layers grown by metal-organic chemical vapor deposition as a Zn diffusion source. A multiquantum-well active region was disordered by Zn diffusion, resulting in band-gap expansion and photoluminescence-wavelength shortening. In this Zn diffusion method, the Zn diffusion length from the active region into the n-cladding layer and the PL-wavelength shortening were easily controlled by controlling the Zn-dopant amount and the Zn-doped GaAs layer thickness. This method is very suitable for mass production. Window lasers fabricated by this method operate at up to 188 mW at 25°C, and as high as 50 mW at 85°C, and 30 mW at 95°C with no COD. The lasers have been operating stably for more than 1200 h at 70°C temperature and 50-mW output power. The mean time to failure was predicted as being more than 37000 h [ABSTRACT FROM PUBLISHER]

High-power and high-temperature operation of 40 mW at 100°C has been realized in 655-nm band multiple-quantum-well (MQW) laser diodes. Both low threshold current density and low optical power density have been achieved by optimizing InGaP-InGaAlP strained MQW separate-confinement heterostructure, high doping for acceptors in p-cladding layer and adopting low-optical-loss high-reflectivity-coating at the rear facet. Fundamental-transverse-mode operation, up to 70 mW, was obtained. High-frequency and large-intensity modulation characteristics above 1 GHz were demonstrated. The relative intensity noise values were as low as -135 dB/Hz under an optical feedback with high-frequency modulation. Stable operation of 30 mW at 70°C over 1000 h was accomplished [ABSTRACT FROM PUBLISHER]

Low operating current and high-temperature operation has been demonstrated in 650-nm AlGaInP high-power laser diodes with real refractive index guided self-aligned (RISA) structure. The RISA structure features an Al0.5In0.5P current blocking layer, which leads to small internal loss in the waveguide and substantially reduced operating carrier density. The resultant operating current for 50-mW continuous-wave at 70°C is as low as 98 mA, which is almost a half of the lowest value ever reported [ABSTRACT FROM PUBLISHER]

The temperature dependence of the differential gain in AlInGaAs 1310-nm vertical-cavity lasers is investigated. The variations in differential gain and in relaxation resonance frequency are shown to depend on the room-temperature offset between the gain peak wavelength and the wavelength of the lasing mode. The tradeoff between high modulation bandwidth and good high-temperature performance for vertical-cavity lasers is analyzed. A cavity mode that is red-shifted about 25 nm from the gain peak is shown to minimize the variation in modulation bandwidth with temperature, and simultaneously allow for satisfactory high-temperature operation. Experimental results are presented and compared to calculated results with excellent agreement. Because of the change in gain-mode offset with internal temperature, the measured modulation current efficiency changed from about 2 to 4.8 GHz/mA12/ for an increase in drive current from 2 to 10 mA. [ABSTRACT FROM PUBLISHER]

We present design criteria for high-temperature operation in 1.3-μm multiple-quantum-well (MQW) lasers from the viewpoint of the light output power penalty, i.e., the change in the light output power at a fixed drive current with increasing temperature. It is shown that not only the characteristic temperature (T0) but also internal loss dependence on temperature (γ) and threshold current (Ith) are significant parameters for reducing the power penalty. We compare the high-temperature performance of InGaAsP-based and AlGaInAs-based MQW lasers and demonstrate that AlGaInAs-based lasers have more potential in terms of the power penalty. Furthermore, we also demonstrate that the power penalty can be reduced by introducing a buried-heterostructure (BH) structure into AlGaInAs-based lasers. From these results, we conclude that the AlGaInAs-based BH lasers are promising for high-temperature performance [ABSTRACT FROM PUBLISHER]

A novel idea of InAlAs native oxide utilized to replace the p-n-p-n thyristor blocking layer and improve the high-temperature performance of the buried heterostructure first proposed and demonstrated. A temperature (To) of 50 K is achieved from an InAlAs native oxide buried heterostructure (NOBH) InGaAsP-InP multiquantum-well laser with 1.5-μm-wide diode leakage passage path. The threshold current and slope efficiency of NOBH laser changes from 5.6 mA, 0.23 mW/mA to 28 mA, 0.11 mW/mA with the operating temperature changing from 20°C to 100°C. It is comparable to conventional p-n reverse biased junction BH laser with minimized diode leakage current, and is much better than the buried ridge strip with proton implanted laterally confinement laser [ABSTRACT FROM PUBLISHER]