Laser Element Dummy Clad Layout for Uniform Waveguide Regrowth
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Solution Overview
Problem
Existing laser element manufacturing processes face challenges in achieving uniform regrowth thickness and composition of passive optical waveguides, leading to quality failures and reduced yield due to process errors during chip cutting.
Innovation Solution
The proposed laser element includes a first clad layer, an optical waveguide, a second clad layer, a first electrode, and dummy clads with specific thickness and composition uniformity, which helps maintain desired SSC widths and improve yield even with process errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive waveguides are regrown in regions between masks using selective area growth, then the active waveguide can be partially etched and passive waveguides can be formed, but the regrowth thickness and composition become non-uniform due to different region areas, leading to quality failure
Solution Approach 1:
The patent applies local quality by making the mask structures have different characteristics in different regions. Specifically, the first mask has a different area than the second mask, which compensates for the different regrowth rates in regions D1 and D2. This ensures that despite the different areas of the regions, the regrowth thickness becomes uniform across both regions by adjusting the mask areas accordingly.
2Reliability
If SSC structures are formed for each chip-unit region, then mode match between laser diode and optical fiber can be achieved, but the width of upper clad layer changes sharply with cutting position, reducing yield
Solution Approach 1:
The patent applies preliminary action by pre-forming the SSC structures and upper clad layers on the entire wafer before chip cutting. The masks are designed with specific areas that compensate for potential cutting position variations. This ensures that even if cutting occurs at different positions (X1 or X2), the SSC structures already have the correct dimensions, preventing yield reduction due to post-cutting width variations.
3Manufacturing precision
If masks of different areas are used for regrowth control, then regrowth thickness uniformity can be improved, but the mask structure becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the area parameter of the masks. The first mask is designed with a different area than the second mask, specifically tailored to compensate for the different regrowth rates in regions D1 and D2. This parameter adjustment (mask area) provides a simple yet effective solution to achieve uniform regrowth thickness without introducing complex mask patterns or additional processing steps.
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 solution enhances the uniformity of regrowth thickness and composition, improving reflection and light-emission performance while maintaining yield and reducing coupling loss, even in the presence of process errors during chip separation.
Implementation Method 1
an optical waveguide disposed on the first clad layer
Implementation Method 2
dummy clads with specific thickness and composition uniformity, which helps maintain desired SSC widths
Data Source
AI summary
Provided are a laser element and a method for manufacturing the same, in which the laser element includes a first clad layer, an optical waveguide disposed on the first clad layer, a second clad layer disposed on the optical waveguide, a first electrode disposed on the second clad layer, and a dummy clad disposed on the optical waveguide and apart from the second clad layer and the first electrode.