8 W continuous wave front-facet power from broad-waveguide Al-free 980 nm diode lasers

Mawst, Luke J.; Bhattacharya, Arnab; Lopez, J.; Botez, D.; Garbuzov, D.Z.; DeMarco, L.; Connolly, J.C.; Jansen, M.; Fang, Fei; Nabiev, R.F.

doi:10.1063/1.117995

Cited by 165 publications

(54 citation statements)

References 12 publications

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“…Since the equivalent ͑transverse͒ spot size 3 is 0.64 m, the catastrophic optical mirror damage ͑COMD͒ power density is 22.5 MW/cm 2 ; that is ϳ40% higher than the COMD power density in cw operation of 0.97 mϫ100 m stripe devices. 1,3 The series resistance, R s , is 0.03 ⍀, that is 3-4 times less than Alcontaining devices of the same contact geometry. Similarly low R s values have been reported 8 for 0.81 m emitting Al-free diode lasers of 200 mϫ2 mm stripe geometry.…”

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confidence: 97%

“…2 Low internal losses and very high external differential quantum efficiencies in BWtype lasers enable the use of 2-to 4-mm-long cavity devices, that have recently allowed the achievement of record-high cw powers for these wavelengths. 3,4 The quasicontinuous wave ͑QCW͒ regime for diode laser operation is important for solid-state laser and fiber laser pumping, as well as for many medical applications, since higher peak output powers are available in the QCW regime than in the cw regime. In the QCW operation the current-pulse duration ͑ ͒ is longer than the diode's thermal time constant, which is about 1 s, so that the laser reaches its steady-state temperature near the beginning of the pulse.…”

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“…1,3 Lasers with high-reflectivity ͑HR-95%͒ and anti-reflective coatings (ARϭ3%), having cavity lengths, L, of 2 or 4 mm, were mounted p side down onto copper submounts measuring 2ϫ11ϫ3 mm 3 . The submounts were bolted to watercooled copper blocks.…”

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14.3 W quasicontinuous wave front-facet power from broad-waveguide Al-free 970 nm diode lasers

Al-Muhanna

Mawst

Botez

et al. 1997

Applied Physics Letters

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Wide-stripe, 0.97 m emitting Al-free InGaAs͑P͒/InGaP/GaAs broad-waveguide separate confinement heterostructure quantum-well lasers demonstrate a record value for quasicontinuous wave ͑QCW͒ output power: 14.3 W ͑100-m-wide stripe, 100 s-wide pulses͒; and reach catastrophic optical mirror damage ͑COMD͒ in QCW operation at an optical power density of 22.5 MW/cm 2 ; that is, 40% higher than COMD levels in cw operation. The devices have low internal losses (␣ i ϭ1 cm Ϫ1 ) and high external differential quantum efficiency ͑86% for 2-mm-long lasers͒, and exhibit only 10-20°C temperature rises in the active region at 10 W QCW power. We also show that long-cavity, large-contact-area devices exhibit relatively little spectral broadening with increased output power. © 1997 American Institute of Physics. ͓S0003-6951͑97͒01235-7͔Broad-waveguide separate confinement heterostructure quantum-well ͑BW-SCH-QW͒ diode lasers have shown high cw powers from Al-free 0.97 m emitting devices 1 as well as from 1.5 m emitting devices. 2 Low internal losses and very high external differential quantum efficiencies in BWtype lasers enable the use of 2-to 4-mm-long cavity devices, that have recently allowed the achievement of record-high cw powers for these wavelengths. 3,4 The quasicontinuous wave ͑QCW͒ regime for diode laser operation is important for solid-state laser and fiber laser pumping, as well as for many medical applications, since higher peak output powers are available in the QCW regime than in the cw regime. In the QCW operation the current-pulse duration ͑ ͒ is longer than the diode's thermal time constant, which is about 1 s, so that the laser reaches its steady-state temperature near the beginning of the pulse. Therefore, the QCW regime is useful to investigate the laser's high-power behavior, since very high peak output powers can be obtained and overheating of the mount and laser itself can be discriminated by varying the current-pulse duration.Here we demonstrate the achievement of record QCW power for ϭ0.97-m-wide stripe (100 mϫ2 mm) lasers, using the BW structure shown in Fig. 1. The QCW result ͑100-s-wide pulses͒ is 14.3 W, which is 80% higher than the best previously published result 5 for 100 m stripe devices. We also show that 200 mϫ4 mm stripe devices have significantly reduced spectral broadening with increased output power compared with devices of smaller stripe area (100 mϫ2 mm).The InGaAs͑P͒/InGaP/GaAs laser structure was grown by low-pressure metalorganic chemical vapor deposition ͑LP-MOCVD͒ in an Aixtron A-200 system on nominally exact-oriented ͑100͒ GaAs substrates. 1 The structure consists of a 1.2-m-wide InGaAsP (E g ϭ1.6 eV) waveguide region, In 0.51 Ga 0.49 P cladding layers, and a p ϩ carbon-doped GaAs cap layer for low contact resistance. The lasing wavelength at 15°C was 0.97 m. Similar structures, for short-cavity length ͑i.e., 0.5 mm͒, have demonstrated record-high cw wallplug efficiency ͑66%͒ values, 6 due to low internal loss and the intrinsically lower series resistance of Al-free devices compared ...

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14.3 W quasicontinuous wave front-facet power from broad-waveguide Al-free 970 nm diode lasers

Al-Muhanna

Mawst

Botez

et al. 1997

Applied Physics Letters

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“…1,2 that is, a structure that concomitantly provides both a large equivalent ͑transverse͒ spot size 3 as well as low internal cavity loss, 1-3 ␣ i (р1 cm…”

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Design considerations and analytical approximations for high continuous-wave power, broad-waveguide diode lasers

Botez

1999

Applied Physics Letters

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118

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Accurate analytical approximations are derived for the equivalent transverse spot size, d/⌫ ͑Ͻ5% error͒, and the transverse beamwidth 1/2 ͑Ͻ2% error͒, of broad-waveguide-type diode lasers, over a wide range in waveguide width: from the first-order-mode cutoff to the third-order-mode cutoff. The analytical formulas are found to be in good agreement with experimental values. For low-series-resistance and thermal-resistance devices, it is found that the junction-temperature rise ⌬T j in continuous wave ͑CW͒ operation is a strong function of both the characteristic temperature T 1 for the external differential quantum efficiency D as well as of the heatsink thermal resistance. If the device has relatively temperature-insensitive D ͑i.e., T 1 տ1000 K) the maximum CW power as well as the power density at catastrophic optical mirror damage, P COMD , are limited, for a given active-region material, only by the heatsink heat-removal ability. For large d/⌫, 0.97 m emitting, 100 m stripe InGaAs/InGaAs͑P͒/GaAs devices with T 1 ϭ1800 K, record-high CW and quasi-CW ͑100 s wide pulses͒ output powers are obtained. The ratio of quasi-CW to CW P COMD values is only 1.3, in contrast to devices of poor carrier confinement and subsequent low-T 1 values ͑ϳ140 K͒, for which the ratio is 1.9, and whose maximum CW powers are ϳ40% less than those obtainable from high-T 1 devices. © 1999 American Institute of Physics. ͓S0003-6951͑99͒03421-X͔In the quest for high continuous-wave ͑CW͒ powers from diode lasers, one key concept has been that of the broad-waveguide ͑BW͒ separate-confinement heterostructure ͑SCH͒;1,2 that is, a structure that concomitantly provides both a large equivalent ͑transverse͒ spot size 3 as well as low internal cavity loss, 1-3 ␣ i (р1 cm Ϫ1) with no sacrifice in wallplug efficiency at high drive levels. 4 As a result, record-high CW powers have been achieved from BW-type devices at wavelengths from the visible to the midinfrared. 4-9Here, we derive for BW-type devices accurate analytical expressions for the equivalent spot size, d/⌫ ͓d is quantumwell͑s͒ thickness and ⌫ the ͑transverse͒ optical-confinement factor͔ and the transverse beamwidth. In addition, we compare record-high CW and quasi-CW ͑QCW͒ data at ϭ0.97 m and determine which parameters are critical for achieving high CW power at catastrophic optical mirror damage ͑COMD͒.From the definition 7 of the internal optical-power density at COMD, P COMD , one can express the maximum CW power aswhere W is the stripe width and R the front-facet reflectivity. It has been established that for conventionally facetpassivated diodes P COMD is a function of the active-region material, 10 being in effect inversely proportional 11 to the surface-recombination velocity s as long as 12 sу10 5 cm/s. That is, for a given active-region material with sу10 5 cm/s and given stripe width, P max,cw directly scales with d/⌫. One main way to increase d/⌫ is to use BW-SCH structures. 3A schematic representation of the BW-SCH laser structure and its optical-mode profile is shown in Fig. 1. ...

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“…GaAs is a III-V compound with a direct bandgap of 1Á42 eV, widely used in infrared LED and LASERs, 26 fiber optic drivers and receivers, high speed microelectronics monolithic microwave frequency integrated circuits (MMIC) 27,28 and high efficiency solar cells.…”

Section: Gaasmentioning

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The potential of III‐V semiconductors as terrestrial photovoltaic devices

Bosi

Pelosi

2006

Progress in Photovoltaics

175

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III-V semiconductors, GaAs and in particular InGaP, are used in many different electronic applications, such as high power and high frequency devices, laser diodes and high brightness LED. Their direct bandgap and high reliability make them ideal candidates for the realisation of high efficiency solar cells: in the past years they have been successfully used as power sources for satellites in space, where they are able to produce electricity from sunlight with an overall efficiency of around 30%. Nowadays, the use of arsenides and phosphides as photovoltaic (PV) devices is confined only to space applications since their price is much higher than conventional Si flat panel modules, the leading PV market technology. But with the introduction of multijunction solar cells capable of operating in high concentration solar light, the area and, therefore, the cost of these cells can be reduced and will eventually find an application and market also on Earth. This article will review the situation of semiconductor solar cell materials, focusing on Si, GaAs, InGaP and multijunction solar cells and will discuss future trends and possibilities of bringing III-V technology from space to Earth

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8 W continuous wave front-facet power from broad-waveguide Al-free 980 nm diode lasers

Cited by 165 publications

References 12 publications

14.3 W quasicontinuous wave front-facet power from broad-waveguide Al-free 970 nm diode lasers

14.3 W quasicontinuous wave front-facet power from broad-waveguide Al-free 970 nm diode lasers

Design considerations and analytical approximations for high continuous-wave power, broad-waveguide diode lasers

The potential of III‐V semiconductors as terrestrial photovoltaic devices

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