VCSEL Array Pumping Laser Gain Medium
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Solution Overview
Problem
Packaged high power edge-emitting laser stacks face issues with astigmatic light output, high divergence, and the need for correction optics, along with separate cooling systems for each component, which complicates their application in high power laser devices.
Innovation Solution
An integrated high power laser device featuring semiconductor surface-emitting diode pump laser arrays mounted directly to a laser gain medium, utilizing vertical-cavity surface-emitting lasers (VCSELs) that eliminate the need for correction optics and share a single cooling system, allowing for efficient and uniform pumping and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If edge-emitting laser diode bars are used to achieve high output power, then power output is improved, but beam quality deteriorates due to astigmatic light output and high divergence requiring correction optics
Solution Approach 1:
The patent inverts the conventional edge-emitting laser design by using surface-emitting VCSELs that emit light perpendicular to the wafer surface. This inversion eliminates astigmatism and produces circular beam profiles without requiring correction optics, thereby maintaining high beam quality while achieving high power output through array scaling.
Solution Approach 2:
The patent transitions from one-dimensional edge-emitting bars to two-dimensional surface-emitting VCSEL arrays. This dimensional change allows for better beam control and eliminates the astigmatic properties inherent in edge-emitting designs, as the vertical cavity geometry produces symmetric circular beams that require no optical correction.
2Power
If multiple separate laser diode bars are stacked to achieve high power, then power output is improved, but device complexity increases due to separate cooling systems for each component
Solution Approach 1:
The patent merges multiple VCSELs into a single integrated array that shares common mounting and cooling infrastructure. The VCSEL array is mounted on a single substrate with a unified heat sink, eliminating the need for separate cooling systems for each laser bar and significantly reducing device complexity while maintaining high power output capability.
Solution Approach 2:
The patent creates a universal mounting platform that serves multiple functions: mechanical support for the VCSEL array, thermal management through a shared heat sink, and optical alignment reference. This multi-functional design eliminates redundant components and simplifies the overall device architecture while enabling high power output.
3Manufacturing precision
If correction optics are added to improve beam quality from edge-emitting lasers, then beam quality is improved, but device complexity and loss of energy increase
Solution Approach 1:
The patent extracts and eliminates the need for correction optics by fundamentally changing the laser emission geometry from edge-emitting to surface-emitting VCSELs. The vertical cavity design inherently produces non-astigmatic circular beams, removing the requirement for additional optical elements and their associated complexity and energy losses.
Solution Approach 2:
The patent converts the potential harm of astigmatic beam profiles into a benefit by using the vertical cavity geometry to produce inherently symmetric circular beams. The design turns what would be a problematic feature in edge-emitters into an advantageous characteristic of surface-emitters, eliminating the need for beam correction.
4Reliability
If separate packages with independent cooling systems are used for laser diode stacks, then reliability is improved through self-contained design, but ease of manufacture deteriorates due to complex assembly
Solution Approach 1:
The patent merges multiple independent laser diode packages into a single integrated VCSEL array module. The array is fabricated as a unified structure on a common substrate with shared thermal management, eliminating the need for complex assembly of multiple separate packages while maintaining reliability through the robust monolithic design.
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 integrated design achieves high power laser light emission with improved beam quality and simplified manufacturing, eliminating the need for correction optics and enabling scalable, efficient cooling, thus enhancing the performance and reliability of high power laser devices.
Implementation Method 1
semiconductor surface-emitting diode pump laser arrays mounted directly to a laser gain medium, utilizing vertical-cavity surface-emitting lasers (VCSELs)
Implementation Method 2
The active laser medium, also referred to as a gain medium, is a material of a specific purity, size and shape which amplifies the beam
Implementation Method 3
The active laser medium, also referred to as a gain medium, is a material of a specific purity, size and shape which amplifies the beam
Implementation Method 4
Heat generated by both the pump diode array and laser gain medium are cooled by a single cooling system
Data Source
AI summary
An integrated, low profile, high power laser light emission device is disclosed. The integrated laser light emission device provides uniform heat dissipation, as well as uniform pumping of the laser gain medium without the need for a pumping cavity. The laser system includes a pump diode array that can be mounted directly to a laser gain medium without intervening correcting optics hardware. Heat generated by the laser light emission device is cooled by a single cooling system. In the laser device, a pump diode array is preferably a Vertical-Cavity Surface-Emitting Laser (VCSEL) array. VCSEL arrays are mounted on the laser gain crystal by a metal cavity frame or metal stilts. The slightly elevated mounting of the VCSEL's enables increased cooling and maximizing the quantity of VCSEL's on the laser gain medium in order to achieve highly efficient and high power laser light output.