Dual-Wavelength Semiconductor Laser Electrode Width Optimization
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Solution Overview
Problem
Existing two-wavelength semiconductor laser devices face challenges in reducing size and manufacturing cost while maintaining high temperature characteristics and optical output, as excessive reduction in element width leads to reduced optical output and signal-to-noise ratio due to polarization ratio reduction and stress generation from thermal expansion coefficient differences.
Innovation Solution
A semiconductor laser device with integrated red and infrared lasers on the same substrate, where the red laser has a wider electrode width than the infrared laser, ensuring higher heat release efficiency and maintaining a desirable polarization ratio, with specific width ranges for each to minimize overall device size and maximize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the element width is excessively reduced to minimize device size, then the device size is reduced, but the optical output and signal-to-noise ratio are reduced due to polarization ratio reduction and stress generation
Solution Approach 1:
The patent applies local quality by differentiating the electrode widths for red and infrared lasers based on their specific requirements. The red laser electrode is designed with a width of 70-90 μm to maintain polarization ratio and optical output, while the infrared laser electrode is designed with a width of 40-60 μm to minimize device size. This localized differentiation allows each laser type to operate optimally within the integrated device structure.
2Volume of moving object
If the element width is excessively reduced to minimize device size, then the device size is reduced, but the high-temperature characteristics are degraded due to stress generation from thermal expansion coefficient differences
Solution Approach 1:
The patent addresses high-temperature characteristics through local quality by optimizing electrode widths specifically for each laser type. The red laser electrode width of 70-90 μm provides sufficient structural support and stress distribution to maintain reliability at high temperatures, while the infrared laser electrode width of 40-60 μm is sufficient for its requirements. This localized optimization ensures both lasers maintain reliable operation under thermal stress.
3Ease of manufacture
If a single substrate is used to integrate multiple laser types, then manufacturing cost is reduced and device size is minimized, but heat release efficiency becomes challenging to optimize for different laser types
Solution Approach 1:
The patent resolves the heat release challenge in integrated devices through local quality by assigning different electrode widths to different laser types. The red laser electrode width of 70-90 μm provides larger heat dissipation area for the red laser, while the infrared laser electrode width of 40-60 μm is optimized for its thermal characteristics. This localized differentiation enables each laser type to efficiently release heat despite being integrated on a single substrate.
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 allows for a smaller, high-power semiconductor laser device with excellent high-temperature characteristics and polarization ratio, effectively balancing heat release and optical output, thus addressing the limitations of existing devices.
Implementation Method 1
a red-side active layer made of an InGaP-based or AlGaInP-based material is interposed between a red-side first conductivity type cladding layer and a red-side second conductivity type cladding layer having a ridge for current injection. The infrared-side active layer made of a GaAs-based or AlGaAs-based material is interposed between an infrared-side first conductivity type cladding layer and an infrared-side second conductivity type cladding layer having a ridge for current injection.
Implementation Method 2
the light emitting element structure of each semiconductor light emitting element is formed by semiconductor layers grown on the same substrate
Data Source
AI summary
A semiconductor laser device has a red laser element and an infrared laser element on a substrate. The red laser element has a double hetero structure in which an InGaP-based or AlGaInP-based active layer is interposed between a first conductivity type cladding layer and a second conductivity type cladding layer having a ridge. The infrared laser element has a double hetero structure in which a GaAs-based or AlGaAs-based active layer is interposed between a first conductivity type cladding layer and a second conductivity type cladding layer having a ridge. Provided that a first electrode formed over the second conductivity type cladding layer has a width W1 in a direction perpendicular to a cavity length direction and a second electrode formed over the second conductivity type cladding layer has a width W2 in a direction perpendicular to a cavity length direction, the relations of W1>W2 and 80 μm≧W2≧60 μm are satisfied.