Guoguang Lu

Vertical-external-cavity surface-emitting lasers operating at different wavelength: design, numerical simulation, and characteristics

We describe design, numerical simulation and characteristics of high-power optical pumped VECSELs at different wavelength (980nm, and 1300nm). The device design realizes the integrating diode-pumped lasers with vertical-cavity surface-emitting laser structure, drawing on the advantages of both. With periodical gain element structure, optical pumped VECSEL is scalable to watt level output. The characteristics such as threshold condition and output power are calculated theoretically. An optimum number of quantum wells and external mirror reflectivity are obtained from the calculation results, and the thermal characteristic is also considered. Finally the calculation results also predict high output power in this kind of device structure.

High-power vertical-cavity surface-emitting lasers bonded with efficient packaging

High-power vertical-cavity surface-emitting lasers (VCSELs) are processed using a wet thermal-selective oxidation technique. The VCSEL chips are packaged by employing three different bonding methods of silver solder, In-Sn solder, and metalized diamond heat spreader. After packaging, optical output power, wavelength shift, and thermal resistance of the devices are measured and compared in an experiment. The device packaged with a metalized diamond heat spreader shows the best operation characteristics among the three methods. The 200 \mu m-diameter device bonded with a metalized diamond heat spreader produces a continuous wave optical output power of 0.51 W and a corresponding power density of 1.6 kW/cm 2 at room temperature. The thermal resistance is as low as 10 K/W. The accelerated aging test is also carried out at high temperature under constant current mode. The device operates for more than 1000 h at 70 ?, and the total degradation is only about 10%.

High power output and temperature characteristics of 1.06μm diode array module

In this paper high power diode array module with an emission wavelength of 1.06μm is presented. The epitaxial structure is an InGaAs/GaAsP strained-compensated single-quantum well structure. Laser bars with a fill factor of 50% are processed and show a good temperature characteristics with a slope efficiency only decreasing from 1.08W/A to 1.06W/A when the temperature of heat sink changes from 20oC to 40o C. The modules CW output power can reach to 68.5W at a current of 80A when the temperature of cooling water is 20o C. The central wavelength is 1059.4nm.

Vertical-cavity surface-emitting lasers fabricated with efficient packaging method

Vertical cavity surface emitting lasers with large aperture were fabricated by using wet oxidation technique at about 420ºC, and the device chips were packaged with three different packaging methods. The optical output power and wavelength shift of the devices were compared experimentally. The device bonded with diamond spreader shows the best performance, and 200µm-diameter device produces a room temperature continuous wave optical output power of 0.51W. The devices with larger aperture size were also fabricated in experiment.

Vertical-external-cavity surface-emitting lasers: numerical simulation, and characterization

Firstly, the vertical external-cavity surface-emiting lasers (VECSELs) device structure and model was given, and the output characteristic was simple calculated. Then, in experiment, the VECSELs were grown, bonded on to the heat sink, and optically pumped by high-power 808nm diode laser array with fiber output module, the light emission spectra were measured. Finally, The thermal characteristic of the VECSELs was investigated by changing the temperature of the substrate.

Temperature characteristics of high power vertical cavity surface emitting lasers

By using oxidation confinement technology high power vertical-cavity surface-emitting lasers are fabricated in experiment. The electrical and optical performance characteristics such as threshold current, efficiency, emission wavelength, and output power are measured under continuous wave (CW) condition at room temperature. The maximum output power is up to watt regime at wavelength of about 980nm. The temperature characteristics of the device are investigated experimentally in detail. The variation in lasing threshold current with temperature is studied. The characteristic temperature T0 of the device is derived, and the value is about 211K. Such a high characteristic temperature T0 of threshold current can lead to good temperature sensitivity of the device. At the same time, the lasing spectrum characteristics with temperature are also measured. The wavelength shift with temperature is just about 0.06nm/K. From the measured results, it is shown that the device can still operate at high temperature condition.

High power vertical cavity surface-emitting laser with high reliability

High-power vertical-cavity surface-emitting lasers with InGaAs/GaAs quantum well active gain region are investigated. By using AlAs oxidation technology, the devices have been fabricated in experiment, and the characteristics of the device are carried out at room temperature. The 300μm-diameter VCSELs have the maximum room temperature continuous wave (CW) optical output power of about 1.1W, and the threshold current of the device is about 0.46A. The life test of the device is carried out in constant current mode. The life test of 300-μm diameter lasers shows that the average lifetime is about 1800h at 80°C. The device degradation mechanism is also discussed in detail.

High Power Diode Pumped Vertical Externalcavity Surface-emitting Lasers (VECSELS)

We describe the theoretical analysis and calculations of the 980 nm high-power diode-pumped vertical external cavity surface emitting laser (VECSEL). The VECSEL with active region of InGaAs/GaAsP/AlGaAs system can be operated near 500 mW in a single transverse mode.

Theoretical results of vertical external cavity surface emitting laser (VECSEL)

We calculate the characteristic parameters of 980 nm infrared vertical external cavity surface emitting laser with the KP method and give the result of the relative longitudinal confinement factor, threshold gain and output power.

High-power VCSELs single devices and 2-D arrays

The high power bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) and laser arrays emitting at 980 nm are reported. Extensive investigations on size scaling behavior of thermal properties of single devices show limits of attainable output characteristics. The maximum continuous wave (CW) output power at room temperature of single devices with aperture size up to 500 μm is as high as 1.95 W. The key characteristics such as maximum output power, wavelength and thermal resistance are discussed. The bottom-emitting arrays of 16 elements and 200 μm aperture size of individual elements show output power of CW 1.35 W at room temperature. The far-field angle is below 17° for all driving current, which is very favorable for focusing or collimating optics.