Thermal and mechanical issues of high-power laser diode degradation

Souto, J.; Pura, José Luis; Jiménez, J.

doi:10.1557/mrc.2018.124

Cited by 8 publications

(7 citation statements)

References 29 publications

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“…Proposed mechanisms driving the thermal and mechanical deterioration of the laser diode that eventually trigger COD. The intrinsic loop leads to a saturation of the heating effect, so that the mechanical degradation of the device must be invoked in order to effectively activate the extrinsic loop that leads to thermal runaway [126].…”

Section: Discussionmentioning

confidence: 99%

“…The intrinsic loop leads to a saturation of the heating effect, so that the mechanical degradation of the device must be invoked in order to effectively activate the extrinsic loop that leads to thermal runaway. Reprinted from [128], © Materials Research Society 2018. The incorporation of the decrease in the thermal conductivity after the plastic regime is reached sets our model apart from other previous descriptions that had specifically considered the size-dependence of this physical property [18,69].…”

Section: The Incidence Of Nanoscale Effects On Catastrophic Optical D...mentioning

confidence: 99%

“…The incorporation of the decrease in the thermal conductivity after the plastic regime is reached sets our model apart from other previous descriptions that had specifically considered the size-dependence of this physical property [18,69]. We have identified the poor power dissipation under these conditions as the fundamental cause leading to COD [128]. If the additional degradation of the thermal conductivity is not considered, the increased laser light absorption that is commonly cited as the main feedback effect launching the COD, is not sufficient to get to the melting point in the QW, and a saturation regime [58] would be reached.…”

Section: The Incidence Of Nanoscale Effects On Catastrophic Optical D...mentioning

confidence: 99%

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confidence: 99%

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Thermomechanical issues of high power laser diode catastrophic optical damage

Souto

Pura

Jiménez

2019

J. Phys. D: Appl. Phys.

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Catastrophic optical degradation (COD) of high power laser diodes is a crucial factor limiting ultra high power lasers. The understanding of the COD process is essential to improve the endurance of the high power laser diodes. The COD is observed as a process in which the active part of the laser diode is destroyed, forming characteristic defects, the so called dark line defects (DLDs). The DLDs are formed by arrays of dislocations generated during the laser operation. Local heating associated with non-radiative recombination is assumed to be at the origin of the COD process. A summary of the methods used to assess the COD, both in real time and post-mortem is presented. The main approaches developed in the last years to model the heat transport in the laser structures under non homogeneous temperature distribution are overviewed. Special emphasis is paid to the impact of the low dimensionality of QWs in two physical properties playing a major role in the COD process, namely, thermal conductivity and mechanical strength. A discussion about the impact of the nanoscale in both physical properties is presented. Finally, we summarize the main issues of the thermomechanical modelling of COD. Within this model the COD is launched when the local thermal stresses generated around the heat source overcome the yield stress of the active zone of the laser. The thermal runaway is related to the sharp decrease of the thermal conductivity once the onset of plasticity has been reached in the active zone of the laser.

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Section: Discussionmentioning

confidence: 99%

Section: The Incidence Of Nanoscale Effects On Catastrophic Optical D...mentioning

confidence: 99%

Section: The Incidence Of Nanoscale Effects On Catastrophic Optical D...mentioning

confidence: 99%

mentioning

confidence: 99%

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Thermomechanical issues of high power laser diode catastrophic optical damage

Souto

Pura

Jiménez

2019

J. Phys. D: Appl. Phys.

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“…As a consequence of the local heating the transparency is lost and the laser radiation can be locally absorbed, resulting in a further increase of the local temperature. Once the thermal stresses induced by the local temperature increase reach the material yield strength a sudden massive formation of dislocations takes place [9]. The presence of dislocations reduces the thermal conductivity [10], leading to an abrupt increment of the local temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal lensing and the micrometric degraded regions on the catastrophic optical damage process of high-power laser diodes

2020

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Catastrophic Optical damage (COD) is one of the processes limiting the lifetime of high-power laser diodes. The understanding of this degradation phenomenon is critical to improve the laser power and lifetime for practical applications. In this paper we analyze the defect propagation inside the cavity of quantum well (QW) highpower laser diodes presenting COD. For this, we studied the effect of highly localized thermal gradients and degraded regions on the laser field distribution. Finite element method (FEM) simulations are compared to experimental cathodoluminescence (CL) measurements. The presence of micrometric hot spots inside the QW induces the thermal lensing of the laser field. The laser self-focusing inside the cavity eventually generates a new hot spot, and, in a repetitive way, a sequence of hot spots would be created. This would account for the propagation of the dark line defects (DLDs) characteristic of this degradation mode.

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