&gt; 360 W and &gt; 70% efficient GaAs-based diode lasers

Crump, P.; Wang, Jun; Crum, Trevor; Das, Samaresh; DeVito, Mark; Dong, Weimin; Farmer, Jason; Feng, Yan; Grimshaw, Mike; Wise, Damian; Zhang, Shiguo

doi:10.1117/12.602577

Cited by 20 publications

(11 citation statements)

References 5 publications

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“…The losses for a single microwave aperture will probably be in the same range, although in the absence of a specific antenna and feed design the uncertainties are larger. The ECH system on the D-IIID fusion experiment has waveguide losses of 2%/40 m and 0.6% per dihedral (sharp) bend [17], so waveguide losses from the gyrotron to the antenna feed can be as small as a few percent, provided the gyrotron is adjacent to the antenna. We take the same nominal value of η ap = 0.83, with the caveat that system trades -for example, locating the gyrotrons in a common building outside the antenna array -could lower the efficiency 10% or more.…”

Section: Aperture Efficiencymentioning

confidence: 99%

A Comparison of Laser and Microwave Approaches to CW Beamed Energy Launch

Kare¹,

Parkin²

2006

AIP Conference Proceedings

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Abstract. One approach to beamed energy propulsion uses a solid heat exchanger to absorb energy from a distant source and transfer it to a working fluid. Systems of this type can be designed using either microwave or laser sources. In general, microwave sources have been expected to be less expensive than lasers for a given power, but to be more limited in range and/or energy density. With the development of high power millimeter-wave sources and low-cost diode laser arrays, both assumptions are open to question. In this paper, we compare current and projected microwave and laser source technologies for a 100-kilogram-class ground-to-orbit launch system and identify key issues affecting the system-level trade between the two approaches.

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Section: Aperture Efficiencymentioning

confidence: 99%

A Comparison of Laser and Microwave Approaches to CW Beamed Energy Launch

Kare¹,

Parkin²

2006

AIP Conference Proceedings

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“…The parts were tested at 5-°C and a flow rate of 0.5lpm, with optical power monitored using NIST traceable power meters. The detailed design and epitaxial structure of these lasers is discussed in earlier publications [2][3][4].…”

Section: -W Laser Bars From 800-nm To 980-nmmentioning

confidence: 99%

Diode laser efficiency increases enable >400-W peak power from 1-cm bars and shows clear path to peak powers in excess of 1-kW

et al. 2006

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Peak optical power from single 1-cm diode laser bars is advancing rapidly across all commercial wavelengths. Progress in material performance is reviewed and we show that current trends imply there is no fundamental barrier to achieving peak powers of 1-kW per 1-cm diode laser bar. For bars with such high peak powers, commercially available reliable devices would be expected to deliver ~ 300-W per bar. Progress to date has allowed us to demonstrate > 400-W peak output from single 1-cm diode laser bars at emission wavelengths from 800-nm to 980-nm. The available range of emission wavelengths has also been increased, with 90-W bars shown at 660-nm and 24W at 1900-nm, complementing the 100-W bar previously demonstrated at 1470-nm. Peak power is seen to correlate closely peak efficiency. Further advances in diode laser efficiency and low thermal resistance packaging technology continue to drive these powers higher. The most critical improvements have been the reduction in the diode laser operating voltage through optimization of hetero-barriers (leading to 73% efficient 100-W bars on copper micro-channel) and a reduction in packaging thermal resistance by optimizing micro-channel performance (leading to < 0.2-°C/W thermal resistance).

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“…High power conversion devices result in lower levels of waste heat being left in the device, minimizing cooling requirements and maximising useful lifetime and useful optical output. Recent publications demonstrate power conversion efficiency in excess of 70 % from high power 1-cm laser diode bars and single emitters [1]. Testing of diode lasers to cryogenic temperatures (< 200 K) helps diagnose the physical mechanisms limiting the performance of diode lasers [2] and also reveals the maximum possible performance [3].…”

Section: Introductionmentioning

confidence: 99%