Xiangang Xu

Voltage reduction of 808 nm GaAsP/(Al)GaInP laser diodes with GaInAsP intermediate layer

GaInAsP layers and GaAsP/ (Al) GaInP laser diodes (LDs) have been grown on GaAs substrates by metalorganic chemical vapor deposition. The GaInAsP layer, which is lattice matched to GaAs, has an intermediate band gap between Ga 0.5 In 0.5 P and GaAs. The GaInP/GaAs heterojunction spikes, especially in the valence band, can be suppressed by introducing this thin GaInAsP layer into the heterostructure interface. The 808 nm GaAsP/ (Al) GaInP LDs with GaInAsP intermediate layer show a reduced operating voltage compared to the conventional LDs with abrupt GaInP/GaAs interface due to the enhanced hole injection. As a result, the power conversion efficiency is improved from 52% to 60% at 350 mW output power. At high current injection, the LD with GaInAsP intermediate layer has higher light power owing to the decreased joule heating.

MOCVD growth of AlGaInP/GaInP quantum well laser diode with asymmetric cladding structure for high power applications

In order to improve the characteristics of the general broad-waveguide 808-nm semiconductor laser diode (LD), we design a new type quantum well LD with an asymmetric cladding structure. The structure is grown by metal organic chemical vapor deposition (MOCVD). For the devices with 100-\mum-wide stripe and 1000-\mum-long cavity under continuous-wave (CW) operation condition, the typical threshold current is 190 mA, the slope efficiency is 1.31 W/A, the wall-plug efficiency reaches 63%, and the maximum output power reaches higher than 7 W. And the internal absorption value decreases to 1.5 cm^{-1}.

TO packaged 650nm red semiconductor laser with transparent window

Highly uniform solid-phase Zn-diffusion technique was developed to fabricate transparent windows for 650 nm red laser diodes (LDs). The maximum output power was up to 120 mW, which is three times higher than that for LDs without window structure. The LDs showed excellent thermal characteristics and aging reliability with TO-can package. The characteristic temperature was estimated to be 85 K in the temperature range of 25~65 °C. The LDs showed stable operation of 10 mW at a high temperature of 75 °C. After aging test of 2000 h, the elevated operation current was less than 3%, compared to the initial value. The predicted life time was over 10000 h for 10 mW operation at 75 °C.

20.8W TM polarized GaAsP laser diodes of 808nm wavelength

In this paper, we present a high power TM Polarized GaAsP laser diode of 808nm wavelength. For high power and narrow beam divergence, an asymmetry broad waveguide structure and a tensile strained GaAsP quantum well were used and the epilayers were grown by low-pressure metalorganic chemical vapor deposition. We have obtained an optical power of 20.86W at 20A without COMD and the vertical farfield of 27°. It is expected that Al-free GaAsP quantum well laser diodes will have good reliability without any facet treatment.

Influence of the upper waveguide layer thickness on optical field in asymmetric heterostructure quantum well laser diode

Asymmetric broad-waveguide separate-confinement heterostructure (BW-SCH) quantum well (QW) laser diode emitting at 808 nm is analyzed and designed theoretically. The dependence of the optical field distribution, vertical far-field angle, and internal loss on different thicknesses of the upper waveguide layer is calculated and analyzed. Calculated results show that when the thicknesses of the lower and upper waveguide layers are 0.45 and 0.3 \mu m, respectively, for the devices with 100-\mu m-wide stripe and 1000-\mu m-long cavity, an output power of 7.6 W at 8 A, a vertical far-field angle of 37°, a slope efficiency of 1.32 W/A, and a threshold current of 189 mA can be obtained.

650 nm GalnP/AlGaInP laser diodes with low threshold and compressively strained MQW active layer

Abstract650 nm AlGaInP/GaInP laser diodes with compressively strained MQW active layer have been successfully fabricated by means of single epitaxy growth. The threshold current is 6.4 mA, at 40 mA CW operation, the fundamental transverse-mode still remains, and the output power and the slope efficiency can reach 34 mW and 1.1 mW/mA respectively. The dead output power in CW operation can reach 66 mW at a saturation current of 88 mA. During 200 h burn in test, the laser diodes show good stabilization with a degradation of less than 8%.

High-volume production of 650nm GaInP/AlGaInP laser diodes

With the support of state key project, Shandong Huaguang Optoelectronics Co. Ltd. realizes the mass production of low threshold current 650nm GaInP/AlGaInP semiconductor laser chips, rapidly. At present, six million 650nm LD chips can be produced per month. The lowest threshold current at 25°C is 7.4mA. The slope efficiency reaches 1.1mW/mA and the output power is 34mW at 40mA CW operation.