DFB Vertical Emission Laser With Grating Coupler for Easier Packaging
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Solution Overview
Problem
Existing light sources, such as VCSELs, face limitations in certain wavelength ranges and optical power reliability, making them less suitable for applications like proximity sensing and biometric sensing, especially in compact electronic devices.
Innovation Solution
An edge-generated vertical emission laser is developed, featuring a distributed feedback (DFB) laser structure and a grating coupler, which enables vertical light emission with reduced thermal resistance and spreading current, facilitating increased packaging options and on-wafer testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If VCSELs are used for vertical light emission, then packaging ease and on-wafer testing capability are improved, but wavelength range and optical power reliability deteriorate
Solution Approach 1:
The patent merges the advantages of VCSELs (vertical emission, easy packaging, on-wafer testing) with the advantages of edge-emitting lasers (superior wavelength range and optical power reliability) by integrating a DFB laser structure with a grating coupler. This hybrid structure allows the laser to emit light vertically from the top surface while maintaining the spectral characteristics of edge-emitting lasers.
Solution Approach 2:
The grating coupler acts as an intermediary element that redirects the light generated by the DFB laser structure from horizontal propagation to vertical emission. This mediator enables the laser to achieve VCSEL-like vertical emission characteristics while maintaining edge-emitting laser performance through the DFB structure.
2Reliability
If edge-emitting lasers are used for horizontal light propagation, then wavelength range and optical power are improved, but packaging complexity and thermal management difficulty increase
Solution Approach 1:
The patent inverts the traditional edge-emitting laser configuration by using a grating coupler to redirect light from horizontal propagation to vertical emission. This inversion transforms the emission direction while maintaining the DFB laser structure's superior optical properties, thereby simplifying packaging to resemble VCSEL configurations.
3Device complexity
If traditional laser structures are used, then manufacturing simplicity is maintained, but thermal resistance and current spreading issues worsen
Solution Approach 1:
The patent applies local quality optimization by designing the DFB laser structure with specific layer configurations and material compositions that enhance thermal conduction pathways. The grating coupler structure is also optimized locally to minimize current spreading while maintaining vertical emission, thereby improving thermal management without compromising manufacturing simplicity.
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
The edge-generated vertical emission laser achieves efficient vertical light emission, enhancing packaging flexibility, increasing laser yield during fabrication, and providing reliable performance across desired wavelength ranges.
Implementation Method 1
The DFB laser structure may generate light that propagates parallel to the active region of the DFB laser structure
Implementation Method 2
The grating coupler may direct the light toward a top surface of the edge-generated vertical emission laser for vertical emission from the top surface
Data Source
AI summary
Configurations for an edge-generated vertical emission laser that vertically emits light and fabrication methods of the edge-generated vertical emission laser are disclosed. The edge-generated vertical emission laser may include a distributed feedback (DFB) laser structure, a grating coupler, and contact layers. Light may propagate through the DFB laser structure, approximately parallel to the top surface of the edge-generated vertical emission laser and be directed by the grating coupler toward the top surface of the edge-generated vertical emission laser. The light may vertically emit from the edge-generated vertical emission laser approximately perpendicular to the top surface of the edge-generated vertical emission laser. Additionally, the contact layers may be n-metal and p-metal, which may be located on the same side of the edge-generated vertical emission laser. These features of the edge-generated vertical emission laser may facilitate ease of testing and increased options for packaging.