Semiconductor Laser Element Decoupled Confinement Heterostructure
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Solution Overview
Problem
Conventional semiconductor laser elements face challenges in suppressing catastrophic optical damage (COD) on the end facet and efficiently confining carriers within the active layer, limiting their high-output operation due to the interdependence of carrier and light confinement structures.
Innovation Solution
A semiconductor laser element with a decoupled confinement heterostructure design, featuring an active layer sandwiched by a p-type clad layer and an extremely thin n-type carrier blocking layer, allowing independent light and carrier confinement, thereby reducing waveguide mode intensity and preventing COD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the structure for confining carriers is used to also confine the waveguide mode (SCH structure), then the device complexity is reduced, but it becomes impossible to freely reduce the light intensity of the waveguide mode in the active layer
Solution Approach 1:
The patent divides the confinement functions into separate structures: the SCH structure confines carriers while the additional buried layer structure confines and absorbs light. This segmentation allows independent optimization of carrier confinement and light intensity control, resolving the contradiction between structural simplicity and light intensity reduction.
Solution Approach 2:
The buried layer acts as an intermediary component between the active layer and the substrate. It specifically targets and absorbs the waveguide mode light without interfering with the carrier confinement function of the SCH structure, enabling independent control of light intensity while maintaining structural efficiency.
2Reliability
If the light intensity of the waveguide mode in the active layer is reduced to suppress COD, then the reliability is improved, but the output power is limited
Solution Approach 1:
The buried layer serves as a mediator that absorbs excess light energy before it can cause COD at the end facets. By positioning the buried layer to absorb the waveguide mode, the patent protects the active layer from damage while allowing higher overall output power to be achieved.
Solution Approach 2:
The patent converts the potentially harmful waveguide mode light that could cause COD into a beneficial effect by using the buried layer to absorb it. The absorbed light energy is dissipated harmlessly, protecting the device while allowing higher pump powers to be used for increased output.
3Temperature
If carriers are efficiently confined within the active layer to improve temperature characteristic, then the temperature stability is improved, but the light intensity concentration in the active layer increases
Solution Approach 1:
The patent segments the functions of carrier confinement and light management into separate structures. The SCH structure handles carrier confinement for temperature stability, while the buried layer handles light intensity control, preventing the harmful concentration of light in the active layer.
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
This design enhances carrier confinement efficiency and reduces light intensity in the active layer, enabling high-output and high-efficiency operation while preventing COD on the end facet.
Implementation Method 1
an n-type carrier blocking layer arranged so as to be adjacent to the active layer, and having a bandgap width equal to or greater than bandgap widths of the barrier layers
Implementation Method 2
an n-type waveguide layer arranged on a side opposite to a side of the n-type carrier blocking layer on which the active layer is arranged
Implementation Method 3
an n-type clad layer arranged on a side opposite to a side of the n-type waveguide layer on which the active layer is arranged
Data Source
Figure 1A
Figure 1B~1D
Figure 2
AI summary
A semiconductor laser element (1) includes an active layer (11), an n-type carrier blocking layer (13) arranged so as to be adjacent to the active layer (11) and having a bandgap width that is equal to or greater than those of barrier layers (11b), an n-type waveguide layer (14) arranged on a side opposite to a side of the n-type carrier-blocking layer (13) on which the active layer (11) is arranged, so as to be adjacent to the n-type carrier blocking layer (13), an n-type clad layer (15) arranged on a side opposite to a side of the n-type waveguide layer (14) on which the active layer (11) is arranged, so as to be adjacent to the n-type waveguide layer (14), and having a bandgap width that is greater than that of the n-type waveguide layer (14), and a p-type clad layer (12) arranged on a side opposite to a side of the active layer (11) on which the n-type carrier blocking layer (13) is arranged, so as to be adjacent to the active layer (11), and having a bandgap width that is greater than those of the barrier layers (11b) and the n-type waveguide layer (14).