Surface-Emitting Laser Structure With Elongated Current Injection
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Solution Overview
Problem
Existing light emitting elements with surface light emitting laser elements struggle to achieve a narrow emission angle, leading to increased lateral spread of light and reduced coupling efficiency, which complicates the design of electronic, sensing, and communication devices.
Innovation Solution
A light emitting element with a laminated structure featuring a current confinement region and elongated planar current injection region, where the current injection region has a specific shape such as an annular or oval shape, and the first and second light reflecting layers are strategically positioned to control the current flow and light emission angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting element structure is used, then the device structure is simple, but the emission angle is large and coupling efficiency is reduced
Solution Approach 1:
The patent introduces a current confinement region that extends in the depth direction (third dimension) beneath the active layer, transforming a two-dimensional current injection problem into a three-dimensional confinement structure. This vertical extension of the current confinement region enables precise control of light emission angle without complicating the horizontal device structure
Solution Approach 2:
The patent modifies the emission angle parameter by controlling the shape and dimensions of the current confinement region. By adjusting the depth and cross-sectional area of the confinement region, the emission angle can be precisely tuned to achieve optimal coupling efficiency while maintaining structural simplicity
2Productivity
If the emission angle is narrowed to improve coupling efficiency, then external optical systems can be simplified, but the light confinement region becomes wider which increases lateral spread
Solution Approach 1:
The patent resolves the trade-off between emission angle and confinement width by utilizing the depth dimension. The current confinement region extends vertically beneath the active layer, allowing narrow emission angles to be achieved through vertical confinement rather than horizontal compression, thus maintaining adequate lateral confinement width
3Productivity
If the light confinement region is expanded to reduce emission angle, then coupling efficiency improves, but the structure becomes more complex
Solution Approach 1:
The patent merges the current injection function and light confinement function into a single integrated current confinement region. This region simultaneously serves as the current injection path and the optical confinement structure, eliminating the need for separate confinement structures and reducing overall device complexity while achieving narrow emission angles
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
The solution effectively reduces the emission angle to 2 degrees or less in the YZ virtual plane and 0.1 degrees or less in the XZ virtual plane, enhancing light confinement, reducing light loss, and improving emission efficiency, allowing for more precise light irradiation and increased output without the need for external optical systems.
Implementation Method 1
laser oscillation occurs by causing laser light to resonate between two light reflecting layers (distributed Bragg reflector layer (DBR layer))
Implementation Method 2
laser light to resonate between two light reflecting layers
Implementation Method 3
a current confinement region that controls an inflow of a current to the active layer is provided... effectively expand the confinement region optically and electrically
Data Source
AI summary
A light emitting element according to the present disclosure includes: a laminated structure 20 in which a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 are laminated; a first light reflecting layer 41 formed on a first surface side of the first compound semiconductor layer 21; a second light reflecting layer 42 formed on a second surface side of the second compound semiconductor layer 22; a first electrode 31 electrically connected to the first compound semiconductor layer 21; and a second electrode 32 electrically connected to the second compound semiconductor layer 22, a current confinement region 52 that controls an inflow of a current to the active layer 23 is provided, and when an axis in a thickness direction of the laminated structure 20 passing through a center of a current injection region 51 surrounded by the current confinement region 52 is defined as a Z axis, a direction orthogonal to the Z axis is defined as an X direction, and a direction orthogonal to the X direction and the Z axis is defined as a Y direction, the current injection region 51 has an elongated planar shape in which a longitudinal direction extends in the Y direction.