Densely-Spaced Laser Diode Alignment via Segmented Submount Metallization
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Solution Overview
Problem
In densely-spaced arrangements of single-emitter laser diodes, individual placement on submounts leads to alignment errors and misalignment due to high-temperature fabrication processes causing bonding material reflow, making it challenging to maintain optical alignment and control each device effectively.
Innovation Solution
An integrated laser structure with pre-aligned light emission areas is attached to a submount with metallized electrodes, allowing for singulation to create separate electrodes and trenches between diodes, ensuring accurate alignment and individual control while using a single submount for multiple diodes, which reduces thermal expansion mismatch and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If single-emitter laser diodes are placed as close to each other as possible in densely-spaced arrangements, then the density of laser diodes per unit area is improved, but alignment errors of the emitter area relative to each other occur
Solution Approach 1:
The invention segments the single submount into multiple discrete mounting positions with individual submounts for each laser diode. This segmentation allows each laser diode to be precisely aligned and mounted on its own dedicated submount, eliminating alignment errors that would occur in densely-spaced arrangements on a single submount, while still achieving high density through the use of multiple independently-aligned units.
2Productivity
If high-temperature fabrication processes are used to form densely-spaced laser diode arrangements, then the integration level is improved, but the bonding material reflows and creates misalignment
Solution Approach 1:
The invention performs preliminary alignment and bonding of each laser diode to its individual submount before the final high-temperature fabrication processes. By pre-aligning and securing each diode-submount pair separately at lower temperatures, the subsequent high-temperature processes can proceed without causing misalignment, as the bonding material has already set in its correct position.
3Manufacturing precision
If individual placement of each laser diode on its associated submount is used, then alignment control is improved, but the device complexity and fabrication difficulty increase
Solution Approach 1:
The invention segments the fabrication process into standardized, repeatable steps for each laser diode-submount pair. Each unit follows the same alignment and bonding procedure, which simplifies the overall fabrication complexity despite the individualized approach. The segmented design allows for modular assembly and reduces the complexity of managing a single complex densely-spaced arrangement.
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 alignment accuracy, reduces emission line misalignment, and increases density of laser diodes within a specific area, while allowing for individual control and efficient thermal management, improving the integration of complex optical systems.
Implementation Method 1
The submount is formed of a dielectric material with a coefficient of thermal expansion (CTE) similar to that of the laser structure itself
Implementation Method 2
The surface of the submount component upon which the laser structure is attached is metallized and used to form the individual electrical contacts to the laser diodes within the integrated laser structure
Implementation Method 3
an integrated laser structure fabricated to include a plurality of separate light emission areas (e.g., laser bar, wafer-based laser structure)
Data Source
AI summary
A densely-spaced single-emitter laser diode configuration is created by using a laser bar (or similar array configuration) attached to a submount component of a size sufficient to adequately support the enter laser structure. The surface of the submount component upon which the laser structure is attached is metallized and used to form the individual electrical contacts to the laser diodes within the integrated laser structure. Once attached to each other, the laser structure is singulated by creating vertical separations between adjacent light emission areas. The submount metallization is similarly segmented, creating separate electrodes that are used to individually energize their associated laser diodes.