Optical Connection Structure Thermal Stress Offset
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Solution Overview
Problem
The efficiency of optical coupling between optical fibers and functional components, such as lens arrays, is compromised due to thermal expansion coefficient mismatches between the holding member and the optical functional component, leading to bending distortion and fluctuations in optical axes, which affects the reliability of optical connections.
Innovation Solution
An optical connection structure that includes a holding member and a distortion suppression member, where the thermal expansion coefficients of the optical functional component and the distortion suppression member are either higher or lower than that of the holding member, sandwiching the holding member between them to offset thermal stresses, thereby reducing optical axis fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the holding member is made of a single material, then the structure is simple and easy to manufacture, but thermal expansion coefficient mismatches cause bending distortion and optical axis fluctuations
Solution Approach 1:
The holding member is constructed as a composite structure with a resin layer and a metal layer, combining materials with different thermal expansion coefficients. The resin layer has a thermal expansion coefficient closer to the optical functional component, while the metal layer provides mechanical strength. This composite structure reduces thermal stress and bending distortion caused by thermal expansion mismatches, thereby improving reliability without significantly complicating manufacturing.
Solution Approach 2:
Different regions of the holding member are made from materials with different thermal expansion coefficients. The resin layer is positioned in contact with the optical functional component to minimize thermal stress, while the metal layer provides structural support. This local differentiation of material properties allows the holding member to simultaneously achieve ease of manufacture and reliability by addressing thermal expansion issues locally.
2Reliability
If the thermal expansion coefficients of surrounding components are made to match the holding member, then thermal stress is reduced, but the design flexibility and adaptability are limited
Solution Approach 1:
Instead of requiring all components to have matching thermal expansion coefficients, the invention applies different material properties locally. The resin layer is specifically selected to have a thermal expansion coefficient matching or close to the optical functional component, while the metal layer provides mechanical strength. This allows the holding member to adapt to various optical components with different thermal expansion characteristics without requiring the entire system to be designed with matched coefficients.
Solution Approach 2:
The resin layer acts as an intermediary between the metal holding member and the optical functional component. It provides a thermal expansion coefficient that is intermediate between the metal and the optical component, thereby reducing thermal stress. This intermediary layer allows the holding member to accommodate optical components with different thermal expansion coefficients, enhancing adaptability while maintaining reliability.
3Manufacturing precision
If a distortion suppression member is added to offset thermal stress, then optical axis alignment is improved, but device complexity increases
Solution Approach 1:
The distortion suppression function is merged into the holding member itself through the composite structure of resin and metal layers. The resin layer inherently suppresses thermal stress and bending distortion due to its matching thermal expansion coefficient, eliminating the need for a separate distortion suppression member. This integration maintains manufacturing precision for optical axis alignment while avoiding the additional complexity of separate components.
Solution Approach 2:
The holding member is designed to perform multiple functions simultaneously: mechanical support, thermal stress reduction, and optical axis alignment. By incorporating the resin layer with specific thermal expansion properties, the holding member becomes a multi-functional component that suppresses distortion inherent to its structure, rather than requiring additional dedicated distortion suppression components.
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 effectively reduces the decline in optical coupling efficiency due to temperature changes, ensuring stable optical axis alignment and maintaining high coupling efficiency by compensating for thermal expansion differences through stress offsetting.
Implementation Method 1
the thermal expansion coefficients of the optical functional component and the distortion suppression member are higher than the thermal expansion coefficient of the holding member. Alternatively, the thermal expansion coefficients of the optical functional component and the distortion suppression member are lower than the thermal expansion coefficient of the holding member
Data Source
AI summary
The optical connection structure includes: optical fibers disposed such that end faces are arranged in a first direction; an optical functional component having a first surface facing the end faces of the optical fibers; a holding member having a second surface facing the first surface and directly or indirectly fixed to the first surface, a third surface facing away from the second surface, and a fiber holding holes extending from the third surface toward the second surface and respectively accommodating the optical fibers; and a distortion suppression member having a fourth surface facing the third surface and directly or indirectly fixed to the third surface and sandwiching the holding member with the optical functional component. Thermal expansion coefficients of the optical functional component and the distortion suppression member are higher or lower than a thermal expansion coefficient of the holding member.