Optical Waveguide Vertical Taper for Low-Loss Hybrid Coupling
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Solution Overview
Problem
Optical connection loss occurs when optical circuits composed of different materials, such as SiPh and PLC, are integrated due to mismatched mode field diameters and core heights, leading to increased coupling loss and manufacturing complexity.
Innovation Solution
An optical waveguide component with a vertical tapered structure is introduced, where the second core is extended to include the first core region, and a protrusion part with a narrowing width is formed to align and match the core heights, reducing mismatch and deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If SiPh circuit is used for high density integration, then small size and high functional integration are achieved, but manufacturing error sensitivity increases and optical characteristics deteriorate
Solution Approach 1:
The patent introduces an optical waveguide component as an intermediary element between SiPh circuits and PLCs. This component includes a first optical circuit (SiPh), a second optical circuit (PLC), and an optical connection part that bridges them. The PLC portion acts as a mediator that is less sensitive to manufacturing errors, thereby improving the overall optical characteristic accuracy while maintaining the compact size benefits of SiPh.
Solution Approach 2:
The patent employs a composite structure combining two different optical circuit technologies (SiPh and PLC) within a single integrated component. The SiPh portion provides high density integration and small size, while the PLC portion provides manufacturing robustness and accurate optical characteristics. This composite approach allows the system to simultaneously achieve both small size and high manufacturing precision.
2Productivity
If SiPh circuit is used for small mode field, then high integration density is achieved, but coupling loss with optical fiber increases
Solution Approach 1:
The patent addresses the mode field mismatch by transitioning from a direct horizontal coupling approach to a vertical coupling architecture. The optical waveguide component uses vertical tapered structures and multi-layer configurations to bridge the mode field diameter difference between SiPh waveguides and optical fibers. This dimensional transition enables efficient coupling while maintaining high integration density.
3Adaptability or versatility
If hybrid integration with butt coupling is used to connect different material optical circuits, then functional integration is achieved, but alignment complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements preliminary alignment actions during the manufacturing process by forming the optical connection part with pre-defined geometric structures. The tapered waveguide sections and positioned coupling regions are created in advance during fabrication, eliminating the need for complex post-manufacturing alignment procedures. This preliminary structuring simplifies both manufacturing and assembly processes.
4Adaptability or versatility
If optical waveguides with different core heights are connected, then different material integration is enabled, but mode field mismatch and coupling loss occur
Solution Approach 1:
The patent employs parameter changes in the waveguide structure to match mode fields across different materials. The optical connection part features tapered sections where the waveguide width and height gradually change, transforming the mode field parameters from the SiPh waveguide to match the PLC waveguide. This gradual parameter transformation minimizes mode field mismatch and reduces coupling loss while enabling integration of different materials.
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 achieves low-loss optical connection by smoothly transitioning the mode field centers and reducing manufacturing errors, thereby enhancing the optical coupling efficiency.
Implementation Method 1
the second core is configured to be extended to the first optical circuit so that a first core region is included in a second core region in a cross section perpendicular to a length direction of the optical waveguide, and the optical connection part has a vertical tapered structure in which the height of the extended second core is lowered from the first optical circuit toward the second optical circuit
Data Source
AI summary
The optical waveguide component of the present disclosure provides a configuration for optically connecting two optical waveguides composed of different materials with low loss. The first optical circuit including the core of a first material and a second optical circuit including a core of a second material are configured on a single substrate. The optical waveguide component of the present disclosure includes an optical connection part between two optical circuits, and has a double structure in which a core cross-sectional region of one optical waveguide is included in a core cross-sectional region of the other optical waveguide between the two optical waveguides. The optical connection part is provided with a protrusion part of the underclad extending along the first core from the high-level surface toward the low-level surface of the underclad toward, and the width of the protrusion part is gradually narrowed toward the second optical circuit.