Light-Emitting Device High-Refractive Index Layer Single-Mode Output
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Solution Overview
Problem
Semiconductor optical amplifiers and laser devices face challenges in achieving high output while maintaining single-mode light beam emission, as increasing the thickness of the n-type light guiding layer beyond 0.6 μm leads to multi-mode light beam output and optical damage due to high light density near the active layer.
Innovation Solution
A light-emitting device with a layer structure featuring a first compound semiconductor layer thicker than 0.6 μm and a high-refractive index layer formed within it, which lowers the optical confinement factor and moves the light field intensity peak away from the active layer, ensuring single-mode conditions by easing cutoff conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the thickness of the n-type light guiding layer is increased to lower the optical confinement factor, then high output is achieved, but the light beam mode becomes multi-mode
Solution Approach 1:
The patent introduces a high-refractive-index layer at a specific position within the light guiding layer to create local refractive index variation. This localized structural modification allows the system to maintain single-mode operation while achieving the desired optical confinement factor reduction for high output power.
Solution Approach 2:
The patent modifies the refractive index parameter by introducing a high-refractive-index layer with different material composition or doping concentration. This parameter change enables precise control over the optical confinement factor while maintaining the single-mode light beam condition.
2Power
If the thickness of the n-type light guiding layer is increased to lower the optical confinement factor, then high output is achieved, but optical damage occurs due to high light density near the active layer
Solution Approach 1:
The high-refractive-index layer is positioned at a specific location within the light guiding layer to locally modify the light field distribution. This creates a region of altered optical properties that redirects light intensity away from the active layer, preventing optical damage while enabling high output power operation.
Solution Approach 2:
The high-refractive-index layer acts as an intermediary structure between the active layer and the surrounding light guiding layer. It mediates the light field distribution by providing a refractive index transition that reduces light density near the active layer, thereby preventing optical damage.
3Duration of action of stationary object
If the thickness of the n-type light guiding layer is increased beyond 0.6 μm, then the optical confinement factor is lowered, but the cutoff conditions for single mode are not satisfied
Solution Approach 1:
The patent changes the refractive index parameter by introducing a high-refractive-index layer, which modifies the waveguide's optical properties. This allows the system to satisfy single-mode cutoff conditions even with a thicker light guiding layer, thereby achieving the desired optical confinement factor while maintaining single-mode operation.
Solution Approach 2:
The light guiding layer is constructed as a composite structure incorporating a high-refractive-index layer within the n-type compound semiconductor material. This composite configuration enables precise control over the optical confinement factor and maintains single-mode operation through engineered refractive index profiling.
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 enables high-output operation with single-mode light beam emission, preventing optical damage and improving light focusing characteristics, suitable for applications with lenses or optical fibers.
Implementation Method 1
a high-refractive index layer formed of a compound semiconductor material having a refractive index higher than a refractive index of a compound semiconductor material of the first compound semiconductor layer is formed in the first compound semiconductor layer
Data Source
AI summary
Provided is a light-emitting device including (a) a layer structure obtained by sequentially growing on a base substrate a first compound semiconductor layer of a first conductivity type, (b) an active layer formed of a compound semiconductor, and (c) a second compound semiconductor layer of a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The layer structure formed of at least a part of the second compound semiconductor layer in a thickness direction of the second compound semiconductor layer. The first compound semiconductor layer has a thickness greater than 0.6 μm. A high-refractive index layer formed of a compound semiconductor material having a refractive index higher than a refractive index of a compound semiconductor material of the first compound semiconductor layer is formed in the first compound semiconductor layer.