Real-time thermal imaging of catastrophic optical damage in red-emitting high-power diode lasers

Ziegler, Mathias; Tomm, Jens W.; Elsaesser, Thomas; Matthiesen, Clemens; Sanayeh, Marwan Bou; Brick, P.

doi:10.1063/1.2898202

Cited by 28 publications

(19 citation statements)

References 12 publications

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“…At a heat-sink temperature of 40°C, one observes the so-called thermal rollover instead of COD. This behavior illustrates that the critical facet temperature [73,74], i. e., T facet = T bulk +ΔT :…”

Section: Cod Threshold In Cw Operationmentioning

confidence: 99%

“…Moreover, the thermal runaway in COD creates a 'thermal flash' of Planck's radiation which can be detected by thermography. Although this 'thermal flash' of infrared emission does not allow for any direct T facet -measurement, it unambiguously indicates the onset of the thermal runaway and can be used for COD analysis [24,74,87,151,152]. This approach will be discussed in chapter 4.…”

Section: Further Approaches For Facet Temperature Analysismentioning

confidence: 99%

“…COD in 650 nm emitting BA lasers with a stripe width of 100 μm has been investigated by Ziegler et al [74,151] in L I-type experiments. Figures 8a-c show thermal images 2.3 ms before, directly at, and 2.3 ms after the onset of the thermal runaway.…”

Section: Review Articlementioning

confidence: 99%

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Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs‐based diode lasers

Tomm

Ziegler

Hempel

et al. 2011

Laser & Photonics Reviews

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Semiconductor lasers are the most efficient manmade narrow-band light sources and convert up to threequarters of electric energy into light. High-power diode lasers are characterized by very high internal power densities in their small cavity, resulting in local heating and sometimes device degradation. Catastrophic optical damage (COD) of diode lasers is a relevant degradation mechanism and limit for reaching ultrahigh optical powers. An overview is given on research activities targeting the mechanisms being relevant for the COD process in GaAs-based diode lasers emitting in the 630-1100 nm range. The discussion of experiments, where COD is artificially provoked, represents the main topic. The sequence of events and fast kinetics taking place on a nanosecond to microsecond time scale are addressed. A particular emphasis is laid on recent experimental work performed in the authors' laboratories. Paving the way for knowledge-based solutions towards more robust diode lasers represents the ultimate goal of this work. COD diagram determined for a batch of broad-area AlGaAs diode lasers. The time to COD within a single current pulse is plotted versus the actual average optical power in the moment when the COD takes place. Full circles stand for clearly identified COD events (right ordinate), whereas open circles (left ordinate) represent the pulse duration in experiments, where no COD has been detected. A borderline (gray) exists between two regions, i. e., parameter sets, of presence (orange) and absence of COD (blue). This borderline is somewhat blurred because of the randomness in filamentation of the laser nearfield and scatter in properties of the involved individual devices.

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Section: Cod Threshold In Cw Operationmentioning

confidence: 99%

Section: Further Approaches For Facet Temperature Analysismentioning

confidence: 99%

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Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs‐based diode lasers

Tomm

Ziegler

Hempel

et al. 2011

Laser & Photonics Reviews

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“…Another mechanism leading to COD is identified that the spatial hole burning effect causes the near-field intensity distributing periodically, such distribution results in an extra enhancement of the facet heating, and the COD occurring finally [9]. Very recently, the dynamics of the COD process under continuous wave operation has been analyzed in redemitting high-power diode lasers by means of combined real-time thermal and optical near-field imaging with cameras, and COD is time-resolved analyzed in singlepulse excitation [10,11]. Additionally, Elliott et al has proposed an explanation for the limiting time at high current and the relationship between the time to COD and the area of damaged facet material using a straightforward thermal model [12].…”

mentioning

confidence: 99%

Transient thermal characteristics related to catastrophic optical damage in high power AlGaAs/GaAs laser diodes

Qiao

Feng

Cong

et al. 2013

Phys. Status Solidi A

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The transient thermal characteristics related to catastrophic optical damage (COD) in high power AlGaAs/GaAs laser diodes (LDs) are studied experimentally by means of thermal infrared imaging, laser scanning confocal microscopy, and transient thermal technique. The transient thermal technique is based on the diode forward voltage method in which the structure function theory is applied to determine the component thermal resistance and temperature rise of the LDs. We have recorded the dynamics of COD process using thermal infrared camera. Two melting spots are observed in the output facet after COD which location exactly matches the position of the thermal flash from the thermal imaging and even the temperature of COD seed has a sudden increase of 32 K when the COD event occurs. Furthermore, we find that the thermal resistance from chip to In solder increases remarkably after COD, meanwhile the thermal resistance of solder and package does not change apparently. The results are attributed to the heat power dissipation increase originating from the enhancement of nonradiative recombination after COD under constant input electrical power.

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“…Facets are the hottest regions in the regular operation of laser diodes and therefore the places where the thermal degradation processes limiting the reliability of high power laser diodes originate 1 " 6 . Facet heating is the result of a complex mechanism which ultimate origins are commonly attributed to the boundary character of the facet giving rise to a concentration of non-radiative defects higher than in the bulk.…”

Section: Introductionmentioning

confidence: 99%

Simulation of facet heating in high-power red lasers

Tijero

Odriozola

Esquivias

et al. 2010

Physics and Simulation of Optoelectronic Devices XVIII

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A two-dimensional self-consistent laser model has been used for the simulation of the facet heating of red emitting AlGalnP lasers. It solves in the steady-state the complete semiconductor optoelectronic and thermal equations in the epitaxial and longitudinal directions and takes into account the population of different conduction band valleys. The model considers the possibility of two independent mechanisms contributing to the facet heating: recombination at surface traps and optical absorption at the facet. The simulation parameters have been calibrated by comparison with measurements of the temperature dependence of the threshold current and slope efficiency of broad-area lasers. Facet temperature has been measured by micro-Raman spectrometry in devices with standard and non absorbing mirrors evidencing an effective decrease of the facet heating due to the non absorbing mirrors. A good agreement between experimental values and calculations is obtained for both devices when a certain amount of surface traps and optical absorption is assumed. A simulation analysis of the effect of non absorbing mirrors in the reduction of facet heating in terms of temperature, carrier density, material gain and Shockly-Read-Hall recombination rate profiles is provided.

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Real-time thermal imaging of catastrophic optical damage in red-emitting high-power diode lasers

Cited by 28 publications

References 12 publications

Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs‐based diode lasers

Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs‐based diode lasers

Transient thermal characteristics related to catastrophic optical damage in high power AlGaAs/GaAs laser diodes

Simulation of facet heating in high-power red lasers

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