The impact of temperature and strain-induced band gap variations on current competition and emitter power in laser bars

Amuzuvi, Christian Kwaku; Bull, S.; Tomm, Jens W.; Nagle, J.; Sumpf, B.; Erbert, G.; Michel, N.; Krakowski, M.; Larkins, E.C.

doi:10.1063/1.3600644

Cited by 14 publications

(12 citation statements)

References 15 publications

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“…Higher currents were drawn and consequently more power emitted towards the centre of the bar compared to the edge [12], Amuzuvi et al [13]. The temperature at the front facet is higher and has a stronger curvature than at the back facet, which is expected (Figure 4).…”

Section: Resultsmentioning

confidence: 58%

By-emitter Emulation Enhancement Tool Using a Global Thermal Solver for the Degradation Emulation of a Calibrated 975 nm Tapered Laser Bar

Amuzuvi¹,

Attachie²,

Asante³

2013

AJEEE

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In this paper, Barlase has been taken a step further by emulating the degradation processes in high power semiconductor laser bars using an upgraded version of Barlase by the introduction of a global thermal solver to further deepen the understanding of the behaviour of laser bars. In this paper, the emulation of a real laser bar was investigated to emulate experimental results by simulating the experimental results in the view of finding a correlation between them. The results established show a more elaborate frown shaped power/current profile and a corresponding frown shaped temperature profile especially at the front facet of the laser bar. Even though a more elaborate frown shaped profile was realised in the power, current and temperature profiles, it fell short from what was seen in the experimental results. As the emulation of laser bar degradation has not been attempted before, further work is needed to achieve better agreement in the output power, current and temperature profiles to better the model.

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Section: Resultsmentioning

confidence: 58%

By-emitter Emulation Enhancement Tool Using a Global Thermal Solver for the Degradation Emulation of a Calibrated 975 nm Tapered Laser Bar

Amuzuvi¹,

Attachie²,

Asante³

2013

AJEEE

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“…Measurements of the emission wavelength shift and measurements at elevated temperatures give A∼1.4 [7]. Theoretical work, where simulated temperature profiles are convolved with the spatial response function of the thermal camera give a value of A∼1.1, but this did not consider the transparency of the substrate to infrared emission.…”

Section: Resultsmentioning

confidence: 99%

“…Xia et al [4], Tomm et al [5], and Bull et al [6] all used a detailed "by-emitter" performance analysis of each emitter to understand the behaviour and degradation of the individual emitters. When emitter temperatures rise, thermal crosstalk between emitters becomes more significant [7]. This paper therefore, seeks to further investigate the effects of temperature on a 975 nm tapered laser bar using convolution to ascertain the dominant effect of temperature on a laser bar.…”

Section: Introductionmentioning

confidence: 99%

Further Investigations into the Effects of Temperature on a 975 nm Tapered Laser Bar Using Convolution to Ascertain the Dominant Effect of Temperature on a Laser Bar

Amuzuvi¹,

Asante²

2014

AJEEE

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Temperature continues to be an issue in the reliability of high power laser diodes. Any effort, therefore, made to understand the dynamics of temperature on the performance of laser diodes is important. This is because it serves as a catalyst for the generation of nonradiative recombination centers, which ultimately kills laser diodes. In this paper, the convolution of simulation results was done to compare it with experimental results, which revealed more details that hitherto, could not have been captured by experiments alone. The inability of experiments to capture these details is due to the limited spatial resolution of the charged-coupled device (CCD) camera, which is approximately 30 µm much larger than the thickness of the quantum well active region used in the experiment. The convolution results showed a further smile-shaped profile within the four groups of array emitters, which in the experimental results, were considered as one emitter due to the limited spatial resolution of the CCD camera. The use of convolution to determine more details was investigated, due to the dominant effect of temperature found across the output power distribution of high power semiconductor laser diode bars.Keywords: by-emitter, emitter, quantum well, defect, non-radiative recombination, degradation, temperature, thermal crosstalk, spatial resolution, convolution, interpolation, charged-coupled

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“…The band gap energy (E g ) drops with increasing temperature (Varshni, 1967), which reduces the turn-on voltage of the hotter emitters. This explains why the central emitters in a bar tend to have more power than those at the edges of bars, resulting in the frown-shaped (Amuzuvi et al, 2011) power emission profiles of the unaged bars.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Facet Heating and the Evolution with Aging

Amuzuvi¹,

Attachie²

2013

RJASET

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This study seeks to explain the effects of thermal runaway due to current competition between emitters in a laser diode bar using both experimental and simulation results. We have demonstrated a trend due to temperature and the evolution with aging using both experimental and simulation results. By-emitter degradation analysis was performed on two bars: 650 nm broad area laser bars and 980 nm tapered laser bars before and after aging. We observed that, a frown shaped temperature profile gave rise to a corresponding frown shaped profile, but the frown shaped power profile turned to a smile shaped profile with the evolution of time. The observed trend was confirmed using simulation results.

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The impact of temperature and strain-induced band gap variations on current competition and emitter power in laser bars

Cited by 14 publications

References 15 publications

By-emitter Emulation Enhancement Tool Using a Global Thermal Solver for the Degradation Emulation of a Calibrated 975 nm Tapered Laser Bar

By-emitter Emulation Enhancement Tool Using a Global Thermal Solver for the Degradation Emulation of a Calibrated 975 nm Tapered Laser Bar

Further Investigations into the Effects of Temperature on a 975 nm Tapered Laser Bar Using Convolution to Ascertain the Dominant Effect of Temperature on a Laser Bar

The Effect of Facet Heating and the Evolution with Aging

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