High-Power Broad-Area Diode Lasers and Laser Bars

Erbert, G.; Bärwolff, A.; Sebastian, J.; Tomm, Jens W.

doi:10.1007/3-540-47852-3_5

Cited by 27 publications

(13 citation statements)

References 65 publications

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“…The characteristics of optical output power P opt and wallplug efficiency vs. current are shown in Figure 2 (a). The pulse spectrum, corresponding to operation at the coolant temperature, is shown in Figure 2 In order to predict the behavior of the 760 nm laser under long-pulse operating conditions, where the junction temperature rises significantly above the coolant temperature, the temperature-dependence of the laser parameters I th and η d can be characterized empirically by exponential relations 6 with T 0 = 126 K and T 1 = 292 K, respectively.…”

Section: Electro-optical Characteristicsmentioning

confidence: 99%

760nm: a new laser diode wavelength for hair removal modules

Wölz¹,

Zorn²,

Pietrzak³

et al. 2015

SPIE Proceedings

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A new high-power semiconductor laser diode module, emitting at 760 nm is introduced. This wavelength permits optimum treatment results for fair skin individuals, as demonstrated by the use of Alexandrite lasers in dermatology. Hair removal applications benefit from the industry-standard diode laser design utilizing highly efficient, portable and light-weight construction. We show the performance of a tap-water-cooled encapsulated laser diode stack with a window for use in dermatological hand-pieces. The stack design takes into account the pulse lengths required for selectivity in heating the hair follicle vs. the skin. Super-long pulse durations place the hair removal laser between industry-standard CW and QCW applications. The new 760 nm laser diode bars are 30% fill factor devices with 1.5 mm long resonator cavities. At CW operation, these units provide 40 W of optical power at 43 A with wall-plug-efficiency greater than 50%. The maximum output power before COMD is 90 W. Lifetime measurements starting at 40 W show an optical power loss of 20% after about 3000 h. The hair removal modules are available in 1x3, 1x8 and 2x8 bar configurations.

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Section: Electro-optical Characteristicsmentioning

confidence: 99%

760nm: a new laser diode wavelength for hair removal modules

Wölz¹,

Zorn²,

Pietrzak³

et al. 2015

SPIE Proceedings

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“…The 9XX nm active region materials are completely aluminum free and benefit from higher facet stability, reduced crystal defects, and better electrical conductivity 3 . As a comparison to the testing shown in the previous section, a number of 50% fill factor, 2 mm long bars were tested with an emission wavelength of 940 nm.…”

Section: Nm Laser Bar Performancementioning

confidence: 99%

Recent advances in actively cooled high power laser diode bars

Ostrom¹,

Roh²,

Grasso³

et al. 2007

SPIE Proceedings

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In order to meet the ever increasing demands of many high power laser diode customers, Nuvonyx has worked to improve a number of key metrics of the diode laser package. The most often challenged specifications are power per bar, efficiency, and reliability in both hard pulse and constant current mode. In response to these requests, Nuvonyx has worked to offer commercial component devices in excess of 100 and 150 watts per bar package in multiple wavelengths. The packages are routinely combined to form single stacks that generate greater than 3.5 kilowatts each and two-dimensional arrays which produce light in excess of 10 kilowatts. These parts all demonstrate predicted lifetimes in excess of 10,000 hours. The micro-channel cooled heat sink has also been improved by closer matching the coefficient of thermal expansion of the cooler to the laser diode bar, which allows for harder solders such as gold-tin to be employed. All of this work has helped to meet the specifications of the most demanding laser diode customers.

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“…Increased active region temperature enhances carrier escape through thermionic emission and increases the rate of non-radiative recombination processes [6]. This causes an efficiency reduction and threshold current increase, resulting in an output power decrease with temperature.…”

Section: Introductionmentioning

confidence: 99%

1.5 and 2.3 μm diode laser arrays for optical pumping

et al. 2005

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High wall-plug efficiency and a wide range of available wavelengths make laser diode arrays preferable for many high-power applications, including optical pumping of solid state lasers. Recently, we designed and fabricated InGaAsP/InP arrays operating at 1.5-µm and In(Al)GaAsSb/GaSb arrays operating at 2.3-µm. We have demonstrated a high continuous-wave (CW) output power of 25 W from a one dimensional laser array and a quasi-CW (q-CW) output power of 110 W from a two dimensional laser array both operating near 1.5-µm. We have obtained a CW output power of 10 W from the 2.3-µm laser array.The 1.5-µm arrays are suitable for resonant pumping of erbium doped solid-state lasers, which require high power optical sources emitting in the narrow erbium absorption bands. Long current-injection pulses produce a considerable temperature increase within the diode laser structure which induces a red-shift of the output wavelength. This thermal drift of the laser array emission spectrum can lead to misalignment with the erbium absorption bands, which decreases pumping efficiency. We have developed an experimental technique to measure the time dependence of the laser emission spectrum during a single current pulse. From the red-shift of the laser emission, we determine the temperature of the laser active region as a function of time.The spacing between the individual laser emitters has an effect on the array heating. In steady state operation, this spacing is a contributing factor in the non-uniformity of the thermal field within the bar, and thus to the overall thermal resistance of the laser bar. Under pulse operation, the transient heating process can be divided into three time periods; each with its own heat transport condition. It was shown that in the initial period of time the heat propagates within the laser bar structure and the laser bar design (fill factor) strongly affects the active region temperature rise. In the later periods the temperature kinetics is insensitive to the fill factor. This analysis has been verified in experimental studies using the 1.5-µm laser arrays.

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High-Power Broad-Area Diode Lasers and Laser Bars

Cited by 27 publications

References 65 publications

760nm: a new laser diode wavelength for hair removal modules

760nm: a new laser diode wavelength for hair removal modules

Recent advances in actively cooled high power laser diode bars

1.5 and 2.3 μm diode laser arrays for optical pumping

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