Wafer-Level Optical Element Modules for 1 mm Active Optical Cables
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Solution Overview
Problem
Conventional active optical cables (AOCs) face challenges in achieving high-speed data transmission with a slimmed structure due to misalignment issues between optical elements, mirrors, and optical fibers, leading to high costs and performance degradation, and require complex manufacturing processes.
Innovation Solution
The solution involves aligning optical element modules and optical fibers using a wafer-level alignment technique without a substrate, integrating them in a System In Package (SIP) form, and utilizing passive alignment to ensure accurate alignment between optical elements and fibers, allowing for a slimmed structure of 1 mm thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional AOC is packaged on a PCB in a bonding or COB form, then the structure is stable and easy to manufacture, but the thickness cannot be reduced to 1 mm or less
Solution Approach 1:
The patent extracts the optical elements (PD/VCSEL devices) from the conventional PCB-based packaging structure and implements them directly on the optical sub-assembly wafer. This extraction eliminates the intermediate PCB layer, enabling the thickness to be reduced to 1 mm or less while maintaining manufacturing feasibility through wafer-level processing
Solution Approach 2:
The patent transitions from a planar PCB-based packaging approach to a three-dimensional wafer-level packaging structure. By stacking optical elements, mirrors, and optical fibers in a vertical arrangement on the wafer, the design achieves thinness in the thickness dimension while distributing components across multiple layers, effectively solving the thickness reduction challenge
2Manufacturing precision
If active alignment is used to achieve accurate alignment between optical elements and optical fibers, then alignment precision is improved, but manufacturing costs increase significantly
Solution Approach 1:
The patent implements preliminary alignment actions by pre-forming alignment marks on the wafer before mounting optical elements and optical fibers. This allows passive alignment to be performed at the wafer level during manufacturing, achieving accurate alignment without requiring expensive active alignment equipment or processes after assembly
Solution Approach 2:
The patent uses alignment marks as geometric copies or representations of the optical element positions. By aligning these marks during wafer-level processing, the actual optical elements and fibers are automatically positioned correctly, eliminating the need for complex active alignment procedures while maintaining high alignment precision
3Reliability
If wire-bonding is used to connect optical elements for high-speed interconnection, then electrical connection is achieved, but signal resistance increases and performance degrades
Solution Approach 1:
The patent extracts the wire-bonding step from the connection process by implementing flip-chip bonding directly between the optical elements and the substrate. This eliminates the intermediate wire-bonding layer, reducing signal resistance and improving high-speed signal transmission quality while simplifying the overall connection structure
Solution Approach 2:
The patent replaces the mechanical wire-bonding system with a direct flip-chip bonding system. Instead of using wires to connect optical elements, the optical elements are bonded directly to the substrate through their connection pads, eliminating the mechanical complexity of wire routing and reducing signal resistance associated with wire connections
4Ease of manufacture
If passive alignment is used without substrate to reduce costs, then manufacturing cost is reduced, but alignment accuracy between optical elements and fibers deteriorates
Solution Approach 1:
The patent performs preliminary alignment actions at the wafer level before final assembly. By pre-forming alignment marks and performing alignment during wafer processing, the patent enables passive alignment to achieve high accuracy without requiring expensive active alignment processes, thus reducing manufacturing cost while maintaining alignment precision
Solution Approach 2:
The patent introduces alignment marks as intermediary elements that mediate between the optical elements and optical fibers. These marks serve as reference points that enable passive alignment to achieve accurate positioning without requiring complex active alignment equipment or processes, thus reducing cost while maintaining precision
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 approach enables high-speed data transmission with accurate alignment, reduces manufacturing costs, and improves productivity by automating the assembly process, while maintaining a compact size and minimizing signal resistance.
Implementation Method 1
a reflective surface is formed on one side of the OSA facing a core of the optical fiber mounted in the OSA; an optical component is installed on the reflective surface of the OSA to transmit an optical signal between the optical fiber and the optical engine
Implementation Method 2
an optical component installed on the reflective surface of the OSA to transmit the optical signal between the optical fiber and the optical engine
Data Source
AI summary
Provided is an optical element module comprising: a mold body having a first surface formed on an upper portion thereof and a second surface formed on a lower portion thereof; an external connection terminal formed on the first surface and electrically connected to the outside; an optical engine embedded and sealed between the first surface and the second surface and having a connection pad exposed to the second surface; a conductive vertical via formed to penetrate the first surface and the second surface and having one end portion electrically connected to the external connection terminal; a wiring layer formed on the second surface to interconnect the other end of the conductive vertical via and the connection pad of the optical engine; and a reflective surface integrally formed on the wiring layer and transmits an optical signal generated by the optical engine or received by the optical engine.