Surface-Emitting Semiconductor Laser With Tunnel Junction
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Solution Overview
Problem
Existing measuring arrangements using semiconductor laser components for distance and speed measurement are inefficient and costly to produce.
Innovation Solution
A measuring arrangement with a radiation device featuring a surface-emitting semiconductor component having multiple active regions connected by a tunnel junction, a detection device, and an evaluation circuit, which increases radiant power and electro-optical conversion efficiency by using a frequency-selective element to reduce radiation intensity in the tunnel junction and a resonator with high reflectivity mirrors to enhance laser activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple active regions are connected in series to increase radiant power, then the total voltage requirement increases, but the manufacturing complexity and cost increase
Solution Approach 1:
The semiconductor body is divided into multiple active regions (first active region, second active region, etc.) that are spatially separated and independently formed within the same crystal structure. Each active region can be independently optimized for its function while contributing to the overall radiant power output through their combined operation
Solution Approach 2:
Multiple active regions are nested within a single semiconductor body, with each region contained within the broader semiconductor structure. The tunnel junction is nested between the active regions, creating a compact integrated design where multiple functional elements coexist within one device package, reducing manufacturing steps compared to assembling separate components
2Loss of energy
If a tunnel junction is integrated between active regions to enable carrier transport, then electro-optical conversion efficiency increases, but manufacturing precision requirements increase
Solution Approach 1:
The tunnel junction is merged with the active regions as an integrated structure within the semiconductor body, rather than being a separate component. This combining of the tunnel junction and active regions into a single monolithic device allows carriers to be transported efficiently between regions while maintaining a simplified manufacturing process that forms all elements in one growth sequence
Solution Approach 2:
The tunnel junction utilizes quantum mechanical tunneling effects by controlling the band structure and doping profiles in the region between active regions. By adjusting parameters such as layer thickness, doping concentration, and material composition during epitaxial growth, the tunneling probability is optimized to achieve high carrier transport efficiency without requiring extremely tight dimensional tolerances
3Loss of energy
If radiation intensity is reduced in the tunnel junction region to prevent absorption, then electro-optical efficiency improves, but laser activity may be suppressed
Solution Approach 1:
Different regions of the semiconductor body are given different optical and electrical properties tailored to their specific functions. The active regions are designed with high gain and low loss characteristics to support laser oscillation, while the tunnel junction region is specifically engineered with reduced radiation intensity and optimized carrier transport properties. This local optimization allows each region to perform its intended function without compromising the overall device performance
Solution Approach 2:
The tunnel junction acts as an intermediary element that facilitates carrier transport between active regions while minimizing its own radiation absorption. By positioning the tunnel junction in regions of low radiation intensity and designing it with appropriate thickness and doping, it serves as an efficient carrier conduit without significantly interfering with the optical field, thus maintaining laser activity while reducing energy loss
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 enhances the efficiency and cost-effectiveness of the measuring arrangement by increasing radiant power, reducing electrical resistance, and improving laser activity, leading to improved distance and speed measurement capabilities.
Implementation Method 1
A tunnel junction is monolithically integrated in the semiconductor body between two active regions from the plurality of active regions. When the semiconductor component is in operation, the two active regions are electrically conductively connected by means of the tunnel junction.
Implementation Method 2
a resonator with high reflectivity mirrors to enhance laser activity
Implementation Method 3
which can be used, for example, for distance measurement or for speed measurement
Implementation Method 4
using a frequency-selective element to reduce radiation intensity in the tunnel junction
Implementation Method 5
The reflection can be directed or diffuse, so that part of the reflected radiation is radiated back in the direction of the detection device
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The arrangement has a radiation unit with a surface emitting semiconductor device (1). The semiconductor device has a semiconductor body (2) with active regions (4a, 4b), which are suitable for producing radiation. The active regions are placed at a distance from each other in vertical direction. A tunnel junction (5) is monolithically integrated in the semiconductor body between the active regions. A detection unit detects reflected radiation. An evaluation circuit is equipped for controlling the radiation and detection units and for processing a detection result of the detection unit.