Semiconductor Laser Ground Layout for High-Frequency Signal Stability
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Solution Overview
Problem
Existing semiconductor laser light source devices face challenges in achieving a favorable pass characteristic for high-frequency signals due to difficulties in electrical connections, high manufacturing costs, and instability of ground levels, particularly with castellations or penetration vias.
Innovation Solution
The device employs a configuration with a metal stem, support blocks, and dielectric substrates where electrical connections are established through metal films on side surfaces, eliminating the need for castellations or penetration vias, thereby stabilizing the ground level and improving high-frequency signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If castellations or penetration vias are used to electrically connect the second support block and ground electrode, then electrical connection is achieved, but manufacturing difficulty increases and cost increases
Solution Approach 1:
The patent extracts the problematic castellations and penetration vias from the structure, replacing them with a simplified ground electrode pattern formed directly on the second dielectric substrate. This removal of complex connection structures eliminates manufacturing difficulties while maintaining electrical connectivity between the second support block and ground.
2Reliability
If castellations or penetration vias are used for electrical connection, then ground connection is established, but ground level stability deteriorates
Solution Approach 1:
The patent implements equipotentiality by designing the ground electrode pattern to extend continuously from the second support block across the second dielectric substrate to the first dielectric substrate. This continuous ground path ensures uniform potential distribution, stabilizing the ground level and preventing potential fluctuations that would occur with discrete castellations or vias.
3Reliability
If castellations or penetration vias are used, then electrical connection is achieved, but degree of freedom in mounting electrically conductive wire decreases
Solution Approach 1:
The patent transitions from three-dimensional castellations protruding from the substrate surface to a two-dimensional ground electrode pattern integrated into the substrate plane. This dimensional change eliminates physical obstructions, providing unlimited freedom for mounting electrically conductive wires at any position without interference from raised structures.
4Ease of manufacture
If castellation or penetration via is positioned away from the stem, then mounting is simplified, but ground strength weakens and pass characteristic deteriorates
Solution Approach 1:
The ground electrode pattern serves multiple functions simultaneously: it provides electrical connection, maintains ground strength through continuous extension toward the stem, and allows flexible wire mounting positions. The pattern can be configured to extend in various directions, universally satisfying both mounting convenience and signal integrity requirements.
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 enhances the pass characteristic for high-frequency signals, reduces manufacturing complexity and costs, and widens the band of cutoff frequencies, leading to improved signal stability and reduced jitter components.
Implementation Method 1
the second dielectric substrate has a side surface located on the first dielectric substrate side, the side surface having a region in which a first metal film electrically connected to the second ground electrode pattern is formed
Data Source
AI summary
A semiconductor laser light source device includes: a metal stem (1); a temperature control module (3) fixed to a front surface of the metal stem (1); a first support block (4) fixed to the temperature control module (3); a first dielectric substrate (5) having a back surface fixed to the first support block (4) and a front surface to which a semiconductor optical modulation element (6) is fixed and on which a first ground electrode pattern (5a) is formed; a second support block (9) fixed to the front surface of the metal stem (1); and a second dielectric substrate (10) fixed to the second support block (9) and having a front surface on which a second ground electrode pattern (10a) is formed. The second dielectric substrate (10) has a side surface located on the first dielectric substrate (5) side, the side surface having a region in which a metal film (13) electrically connected to the second ground electrode pattern (10a) is formed, the region having a length that is at least equal to or larger than half a length of the side surface.