Silicon Substrate Guide-Pin Alignment for Low-Loss Fiber Coupling
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Solution Overview
Problem
Active optical alignment for silicon photonics requires time and effort, and passive alignment lacks accuracy, leading to increased connection loss.
Innovation Solution
A positioning structure for a silicon substrate using guide pins and grooves with precise angles defined by silicon crystal planes, combined with a connector receiving portion and a ferrule, allows for high-accuracy passive alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active optical alignment is used to position the optical connection component, then connection accuracy is improved, but time consumption and operational complexity increase
Solution Approach 1:
The guide pins are pre-positioned on the silicon substrate before the optical connection component is attached. These guide pins extend beyond the substrate surface to serve as pre-established positioning references, enabling accurate alignment without requiring time-consuming active adjustment during the connection process.
Solution Approach 2:
The guide pins automatically provide positioning functionality through their physical presence on the substrate. The connector receiving portion and ferrule naturally align with the guide pins during assembly, allowing the system to self-position without requiring external active alignment operations or complex adjustment mechanisms.
2Loss of time
If passive alignment is used to position components, then time consumption is reduced, but connection accuracy deteriorates leading to increased connection loss
Solution Approach 1:
The patent replaces complex mechanical active alignment adjustment mechanisms with a simple geometric positioning system. The guide pins combined with the connector receiving portion and ferrule create a passive mechanical interlock that automatically ensures accurate positioning through their predetermined geometric relationships, eliminating the need for active optical adjustment while maintaining high connection accuracy.
3Ease of manufacture
If guide pins are positioned using conventional methods, then ease of manufacture is improved, but positioning precision deteriorates
Solution Approach 1:
The guide pins are positioned using the natural crystal orientation parameters of silicon, specifically the <100> substrate plane and <111> crystal planes. By leveraging the inherent geometric parameters of the silicon crystal structure rather than relying on conventional external positioning methods, the system achieves high positioning precision while maintaining ease of manufacture through standard semiconductor fabrication processes.
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
Enables low-loss, high-accuracy connection between silicon substrates and optical fibers without active alignment, achieving alignment errors of 1.7 μm or less.
Implementation Method 1
The groove may have a V-shaped or inverted trapezoidal cross-sectional shape. The substrate surface may be a (100) plane of a silicon crystal forming the silicon substrate, and a surface of the groove may include at least two (111) planes of the silicon crystal. The guide pin may be positioned with respect to the silicon substrate by a cylindrical side surface of the guide pin being in contact with each of the two (111) planes.
Data Source
AI summary
A positioning structure for a silicon substrate includes a silicon substrate and a guide pin. The silicon substrate includes a substrate surface in which at least one groove having a linear shape is formed. The guide pin is positioned along the at least one groove. The at least one groove reaches a side surface of the silicon substrate, and the guide pin extends beyond the side surface to the outside of the silicon substrate.