Optical Transmitter Resin Layout for Thermal Warp Compensation
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Solution Overview
Problem
Optical transmitters face a decrease in light output at high temperatures due to warping of the housing, which causes the optical axis to deviate from the center of the optical fiber, leading to reduced light transmission.
Innovation Solution
The use of resins with different coefficients of thermal expansion on the emission and light emitting element sides of the housing, where the first resin has a smaller coefficient than the second resin, helps to minimize warping effects by reducing the received light amount of the light receiving element, thereby increasing the light emitting power and suppressing the decrease in output light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the housing is made rigid to maintain structural stability, then the housing warping at high temperatures increases, but the light transmission efficiency decreases due to optical axis deviation
Solution Approach 1:
The patent changes the material composition parameter of the housing by incorporating a resin layer with specific thermal expansion characteristics between the light emitting element and the housing body. This resin layer's thermal expansion coefficient is designed to match or compensate for the differential expansion between the light emitting element and housing, thereby maintaining optical alignment at high temperatures while preserving structural stability.
Solution Approach 2:
The housing structure uses a composite material system consisting of the housing body, resin layer, and light emitting element mounting structure. This composite structure allows different components to have different thermal expansion characteristics, with the resin layer acting as a buffer to accommodate thermal mismatch and prevent optical axis deviation during temperature variations.
2Measurement precision
If the light receiving element is positioned to monitor output light effectively, then the monitoring precision improves, but the received light amount decreases due to warping-induced optical axis deviation
Solution Approach 1:
The patent positions the light receiving element with specific angular orientation relative to the optical axis, and uses the resin layer to maintain this angular relationship at high temperatures. The resin's thermal expansion characteristics ensure that the light receiving element's position and orientation parameters remain stable, preserving both monitoring precision and light reception efficiency during temperature variations.
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 influence of warping on light output, maintaining light transmission efficiency even at high temperatures by adjusting the resin expansion and inclination angles, ensuring consistent power delivery to the optical fiber.
Implementation Method 1
a first resin located on an emission end side of a lower side of the carrier, and a second resin located on a light emitting element side of the lower side of the carrier. A coefficient of thermal expansion of the first resin is smaller than a coefficient of thermal expansion of the second resin
Data Source
AI summary
An optical transmitter according to one embodiment includes a housing with an emission end, a light emitting element mounted on a first mounting portion of the housing, and a light receiving element mounted on a second mounting portion of the housing to monitor output light from the light emitting element. The second mounting portion is provided with a carrier, a first resin located on an emission end side of a lower side of the carrier, and a second resin located on a light emitting element side of the lower side of the carrier. A coefficient of thermal expansion of the first resin is smaller than a coefficient of thermal expansion of the second resin.