Optical Semiconductor Device Impedance Matching
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Solution Overview
Problem
Conventional optical semiconductor devices experience increased signal reflection and loss due to deviations in characteristic impedance of the transmission path, which affects high-speed communication performance.
Innovation Solution
The optical semiconductor device incorporates a base with a specific design featuring a bottom wall, side wall, and flange, along with a wiring substrate and sub-mount, where the sub-mount is fixed to a higher seat and the wiring substrate's distal portion is flush with the optical element, optimizing bonding wire length and impedance matching to improve signal transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mounting structures are used, then device assembly is simple, but signal transmission characteristics deteriorate due to impedance deviation and reflection
Solution Approach 1:
The mounting structure is segmented into distinct functional elements: a base with a first seat for the optical element, a second seat for the wiring substrate, and a positioning protrusion. This segmentation allows each component to be optimized independently for its specific function while contributing to overall impedance control and signal transmission quality.
Solution Approach 2:
The wiring substrate is positioned on the second seat such that its distal end is preliminarily aligned with the optical element before final assembly. The positioning protrusion预先 (in advance) establishes the correct spatial relationship, ensuring that when bonding wires are connected, the impedance characteristics are already optimized rather than requiring post-assembly adjustments.
2Loss of energy
If bonding wire length is not optimized, then manufacturing is easier, but signal loss increases
Solution Approach 1:
The second seat is designed at a specific height relative to the first seat, creating an equipotential positioning system. This ensures that the distal end of the wiring substrate automatically aligns at the optimal position for minimum bonding wire length when the substrate is placed on the second seat, eliminating signal loss without requiring complex active control during manufacturing.
Solution Approach 2:
The positioning protrusion and second seat work together to enable the wiring substrate to self-position at the correct location. The structure automatically ensures optimal alignment between the wiring substrate distal end and the optical element, allowing the assembly process to achieve precise positioning without requiring additional external positioning mechanisms or complex manufacturing procedures.
Data Source
AI summary
An optical semiconductor device includes a base, a wiring substrate, and a sub-mount. The base includes a bottom wall, a side wall projecting from a peripheral edge of the bottom wall, and a flange extending outward from an upper end of the side wall. The wiring substrate includes a distal portion inserted into and fixed to the base. An optical element is mounted on the sub-mount. The bottom wall of the base includes a first seat to which the sub-mount is fixed and a second seat to which the distal portion is fixed. The second seat is located at a higher position than the first seat. An upper surface of the distal portion of the wiring substrate includes a pad connected to the optical element. An upper surface of the pad of the distal portion is flush with an upper surface of an electrode of the optical element.