Thermomechanical degradation of single and multiple quantum well AlGaAs/GaAs laser diodes

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

doi:10.1016/j.microrel.2017.07.005

Cited by 8 publications

(3 citation statements)

References 16 publications

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“…The thermal stresses are concomitantly raised, and both effects are accentuated as more quantum wells form the active part of the device. These results are consistent with the observed higher resilience to degradation of single QW lasers in high power applications [127]. Proposed mechanisms driving the thermal and mechanical deterioration of the laser diode that eventually trigger COD.…”

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

confidence: 88%

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: The Incidence Of Nanoscale Effects On Catastrophic Optical D...supporting

confidence: 88%

Thermomechanical issues of high power laser diode catastrophic optical damage

Souto

Pura

Jiménez

2019

J. Phys. D: Appl. Phys.

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“…For the experiment comparison, three real examples (Train wheel diameter wear degradation, 38,41 GaAs laser electric current degradation, 42 and alloy steel crack degradation. 43 ) are used as the experiment datasets.…”

Section: Actual Experimentsmentioning

confidence: 99%

SVAE‐GRU‐based degradation generation and prediction for small samples

Shangguan

Feng

et al. 2023

Quality & Reliability Eng

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The degradation process analysis is the basis of the system reliability assessment. Too few degradation samples will affect the accuracy of the reliability analysis. So, it is necessary to expand the degradation data and construct the degradation prediction model. This paper proposes an SVAE‐GRU‐based degradation generation and prediction model to handle the issues. New degradation data are generated by combining the Stacked Variational Autoencoder (SVAE) and Gated Recurrent Units (GRU) in each time step, which can improve the learning effectiveness of the degradation features. The GRU and the Multi‐layer perceptron calculate the mean and the variance of the degradation distribution for each timestamp, the deeply heterogeneity and temporal feature of the original degraded samples are learned. Then the degradation amount of different samples are predicted. The optimal hyper‐parameters of the SVAE‐GRU are obtained by the grid search method. To verify the effectiveness of the proposed method, three datasets and four methods are used for experiment comparison in this paper. The actual example indicate that the SVAE‐GRU method has the best effect on the degradation generation and prediction.

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“…In previous works, we have set-up a thermomechanical model accounting for COD [13][14][15]. This model has been further refined [16,17], by focusing on the role played by the nanoscale size of the active layers of the laser [18] and different types of laser structures [19,20]. The propagation of the DLDs, however, has not comparatively received such a wide attention [8].…”

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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Thermomechanical degradation of single and multiple quantum well AlGaAs/GaAs laser diodes

Cited by 8 publications

References 16 publications

Thermomechanical issues of high power laser diode catastrophic optical damage

Thermomechanical issues of high power laser diode catastrophic optical damage

SVAE‐GRU‐based degradation generation and prediction for small samples

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

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