Tapered Waveguide Optical Amplifier for Peak Power
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Solution Overview
Problem
Existing semiconductor optical amplifiers (SOAs) face challenges in increasing peak power of laser beams while maintaining beam width, leading to potential catastrophic optical damage and decreased optical amplifying efficiency due to beam width narrowing.
Innovation Solution
An optical amplifier with a diffusing unit driven by a first current density to increase the beam diameter of the laser beam through a tapered waveguide, followed by an amplifying unit driven by a higher second current density to amplify the intensity of the laser beam, thereby suppressing beam width narrowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the peak power of the laser beam is increased in an SOA, then the output intensity is improved, but the beam width becomes narrower
Solution Approach 1:
The SOA is divided into two distinct units: a diffusing unit with a tapered waveguide that increases beam diameter, and an amplifying unit that provides optical amplification. This segmentation allows each unit to perform its specific function optimally without the negative effects affecting the other.
Solution Approach 2:
The diffusing unit performs the action of increasing beam diameter before the laser beam enters the amplifying unit. By preliminarily expanding the beam width, the subsequent amplification process occurs on a wider beam, preventing the narrowing effect that would otherwise occur during high-power amplification.
2Loss of energy
If the beam width is maintained while increasing peak power, then optical amplifying efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The diffusing unit and amplifying unit are merged into a single integrated SOA device structure, sharing common elements such as the semiconductor active layer and electrical contacts. This integration achieves the desired functional combination while minimizing the increase in device complexity compared to using completely separate components.
Solution Approach 2:
Different regions of the SOA are designed with different local properties: the diffusing unit has a tapered waveguide geometry optimized for beam expansion, while the amplifying unit has a uniform waveguide optimized for optical gain. Each local region is optimized for its specific function while contributing to the overall device performance.
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 increases peak power and maintains a stable beam width, preventing catastrophic optical damage and enhancing optical amplifying efficiency.
Implementation Method 1
a diffusing unit configured to be driven by a first current density and to increase a beam diameter of an incident laser beam
Implementation Method 2
causes stimulated emission in a semiconductor layer with a laser beam incident on the semiconductor layer that is made in an inverted distribution state by supplying predetermined current, and amplifies the intensity of the laser beam
Data Source
AI summary
There is provided an optical amplifier including a diffusing unit configured to be driven by a first current density and to increase a beam diameter of an incident laser beam that passes through a first waveguide that guides the laser beam, and an amplifying unit configured to be driven by a second current density that is higher than the first current density and to amplify intensity of the laser beam that passes through a second waveguide that guides the laser beam whose beam diameter has been increased by the diffusing unit. The first waveguide of the diffusing unit has a tapered shape in which a cross-sectional area of the first waveguide is gradually increased toward a travelling direction of the laser beam.