Semiconductor Laser Grating Pitch Variation for Defect Suppression
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Solution Overview
Problem
The existing semiconductor laser devices face issues with defects in semiconductor layers due to inhomogeneous growth conditions at the boundaries between diffraction gratings, leading to degraded luminescent efficiency and laser performance.
Innovation Solution
A semiconductor laser device design featuring a first diffraction grating with a second diffraction grating continuous to one end, where the second diffraction grating has a pitch 1.05 times or greater, or 0.95 times or smaller of the first diffraction grating pitch, and a manufacturing method involving continuous electron beam exposure to form these gratings, preventing defects from spreading into the active layer and optimizing laser oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a diffraction grating is formed using electron beam exposure with spaces between adjacent gratings, then the gratings can be manufactured, but defects arise at the boundaries between gratings and non-grating areas, degrading luminescent efficiency
Solution Approach 1:
The patent applies homogeneity by making the second diffraction grating continuous with the first diffraction grating without any spaces or boundaries. This continuous structure eliminates the inhomogeneous growth conditions that occur at boundaries between gratings and non-grating areas, preventing defects and maintaining uniform luminescent efficiency across the entire device.
2Measurement precision
If the pitch of the second diffraction grating is significantly different from the first, then laser oscillation wavelength can be controlled, but the second grating may adversely affect laser oscillation
Solution Approach 1:
The patent applies parameter changes by setting the pitch of the second diffraction grating within a specific range (0.95 to 1.05 times the pitch of the first diffraction grating). This controlled parameter variation allows for precise laser oscillation wavelength control while preventing the second grating from adversely affecting laser oscillation stability.
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 design effectively suppresses defects and maintains consistent growth conditions, enhancing the luminescent efficiency and performance of the semiconductor laser device by ensuring the second diffraction grating does not affect the laser oscillation wavelength.
Implementation Method 1
When a diffraction grating is formed on a wafer using the electron beam exposure
Data Source
AI summary
A semiconductor laser device having a diffraction grating is disclosed. The semiconductor laser device comprises a first diffraction grating provided on a substrate, a second diffraction grating continuous to one end of the first diffraction grating along an optical waveguide direction, and an active layer provided above the first diffraction grating. The second diffraction grating has a pitch 1.05 times or greater, or 0.95 times or smaller of the pitch of the first diffraction grating.