Multi-Active Layer Semiconductor Laser Waveguide Design
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Solution Overview
Problem
Semiconductor laser devices that lase in the fundamental mode have limitations in increasing the optical confinement factor, restricting the reduction of threshold current and electrical-to-optical power conversion efficiency.
Innovation Solution
The semiconductor laser device is designed to operate in multiple modes by incorporating a plurality of active layers positioned near the extreme points of the electric field within the optical waveguide, enhancing the optical confinement factor and reducing the threshold current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the optical confinement factor in the active layer is increased to reduce threshold current, then electrical-to-optical power conversion efficiency is improved, but there is a limit to increasing the optical confinement factor in the waveguide structure of semiconductor laser devices that lase in the fundamental mode
Solution Approach 1:
The active layer is divided into multiple discrete active layers positioned at specific locations corresponding to extreme points of the electric field distribution. This segmentation allows each active layer to independently contribute to optical confinement at different spatial positions, achieving higher overall optical confinement factor without requiring continuous modification of the waveguide structure
Solution Approach 2:
The invention transitions from a single active layer configuration to a multi-layer configuration distributed along the vertical dimension of the waveguide. By positioning active layers at multiple heights corresponding to electric field extreme points, the solution exploits the vertical dimension to enhance optical confinement beyond what a single planar active layer can achieve
2Reliability
If multiple active layers are added to increase optical confinement factor, then threshold current is reduced, but the device structure becomes more complex
Solution Approach 1:
Each active layer is positioned at a specific location corresponding to extreme points of the electric field distribution, giving different spatial regions of the waveguide different functional properties. This local quality approach ensures that active layers are placed where they will be most effective at confining optical energy, rather than uniformly distributing them throughout the structure
Solution Approach 2:
The invention changes the spatial parameters (positions and spacing) of active layers to match the electric field distribution characteristics. By adjusting the vertical positions of active layers to coincide with extreme points of the electric field, the system optimizes optical confinement without requiring an excessive number of layers
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 configuration allows for increased electrical-to-optical power conversion efficiency while avoiding mode competition, as the device preferentially lases in higher order modes, reducing power consumption and improving performance.
Implementation Method 1
increasing the optical confinement factor in the active layer(s)
Implementation Method 2
permitting lasing in a crystal growth direction in at least three modes including the fundamental mode
Data Source
AI summary
A semiconductor laser device includes: an n-type cladding layer; a p-type cladding layer; and an optical waveguide portion disposed between the n-type and p-type cladding layers and including spaced-apart active layers. The optical waveguide portion permits lasing in a crystal growth direction of the active layers in at least three modes, including the fundamental mode and two higher order modes. The number of active layers is equal to or greater than the number of extreme points of the electric field of a particular one of the higher order modes. At least one of the active layers is disposed near each extreme point of the electric field of the particular higher order mode, within the optical waveguide portion.