Edge-Emitting Laser Bar Trenches for Facet Heat Isolation
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Solution Overview
Problem
AlInGaN-based laser bars face high processing efforts, thermal stress, and adjustment tolerances due to the difficulty in transferring GaAs-based laser bar technology, with low acceptor activation and increased risk of facet damage leading to failure.
Innovation Solution
Incorporating a thermal decoupling structure between individual emitters with a cooling element that is electrically isolated from the semiconductor layer sequence, reducing heat exchange and facilitating efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple individual emitters are integrated into a laser bar to increase output power, then the productivity and power output are improved, but thermal stress and heat exchange between emitters increase leading to facet damage and reduced reliability
Solution Approach 1:
The laser bar is segmented into multiple individual emitters that are electrically and thermally isolated from each other through deep trenches. This segmentation allows each emitter to be independently controlled and cooled, preventing heat accumulation and thermal stress that would otherwise lead to facet damage, while maintaining high total output power through the combined operation of multiple emitters.
Solution Approach 2:
Deep trenches filled with insulating material act as thermal intermediaries between adjacent emitters. These trenches block heat flow paths between emitters, reducing thermal coupling and preventing the heat exchange that causes thermal stress and facet damage, while allowing the laser bar to operate at high power levels.
2Illumination intensity
If GaAs-based laser bar technology is transferred to AlInGaN-based materials to achieve blue laser radiation, then the wavelength range is improved, but the acceptor activation is low and processing complexity increases
Solution Approach 1:
The patent employs specific parameter changes in the AlInGaN material composition, including optimizing the aluminum and indium content ratios and using precise doping concentrations. These parameter adjustments improve acceptor activation and reduce processing complexity by achieving better material properties that are easier to work with during fabrication, while maintaining the desired blue wavelength output.
Solution Approach 2:
The laser bar uses composite AlInGaN semiconductor layers with specific compositional gradients and heterostructure designs. These composite material structures optimize both the optical properties for blue radiation and the electrical properties for efficient carrier injection, reducing processing difficulties associated with low acceptor activation in AlInGaN materials.
3Reliability
If thermal decoupling structures with deep trenches are introduced between emitters to reduce heat exchange, then the reliability is improved by preventing facet damage, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The deep trenches physically segment the laser bar structure into isolated emitter regions. This segmentation approach, while increasing structural complexity, provides effective thermal isolation that prevents facet damage. The modular nature of the segmented structure also facilitates standardized manufacturing processes despite the increased structural detail.
Solution Approach 2:
The harmful thermal coupling between emitters is extracted and removed from the system by introducing deep trenches that eliminate heat flow paths. This extraction of the problematic thermal interaction simplifies the thermal management problem, allowing each emitter to be independently optimized without concern for heat exchange with neighbors, despite the added structural complexity of the trenches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents facet damage and reduces thermal stress, enhancing the reliability and efficiency of AlInGaN-based laser bars by effectively managing heat exchange between emitters.
Implementation Method 1
a cooling element which is electrically isolated from the semiconductor layer sequence and which is configured to dissipate heat
Implementation Method 2
a thermal decoupling structure between two adjacent individual emitters, which counteracts a heat exchange between the two adjacent individual emitters
Data Source
AI summary
An edge emitting laser bar is disclosed. In an embodiment an edge-emitting laser bar includes an AlInGaN-based semiconductor layer sequence having a contact side and an active layer configured to generate laser radiation, a plurality of individual emitters arranged next to each other and spaced apart from one another in a lateral transverse direction, each emitter configured to emit laser radiation and a plurality of contact elements arranged next to each other and spaced apart from one another in the lateral transverse direction on the contact side for making electrical contact with the individual emitters, each contact element being assigned to an individual emitter, wherein each contact element is electrically conductively coupled to the semiconductor layer sequence via a contiguous contact region of the contact side so that a current flow between the semiconductor layer sequence and the contact element is possible via the contact region.