Surface-Emitting Laser Module With Phase Correction for Fiber Coupling
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Solution Overview
Problem
Conventional high-power surface-emitting laser diode modules face limitations in achieving high brightness and efficient fiber laser pumping due to issues such as large emitting area, high divergence, and etendue limitations, which prevent them from meeting the required beam parameter product and power levels.
Innovation Solution
A laser module design featuring optically decoupled lasing units with coherent elements that are mutually coupled for interference, combined with phase correctors and focusing optics to produce beams with a single main lobe, allowing for high brightness and efficient coupling into an optical fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional VCSEL arrays are used to achieve high power, then the emitting area must be increased, but the beam divergence increases and etendue limitations prevent efficient fiber coupling
Solution Approach 1:
The patent divides the laser system into multiple independent lasing units, each with its own VCSEL array operating at a lower power level. These segmented units are arranged in a planar configuration and can be independently controlled, allowing the system to achieve high total power while maintaining the brightness characteristics of individual low-power units. This segmentation avoids the etendue problem that arises when simply increasing the area of a single high-power VCSEL array.
Solution Approach 2:
The patent transitions from a vertical stacking approach to a planar two-dimensional arrangement of lasing units. By organizing multiple VCSEL arrays in a flat plane rather than stacking them vertically, the system achieves high power output through lateral expansion in two dimensions while maintaining compact vertical profile. This dimensional reorganization allows for improved heat dissipation and optical coupling efficiency.
2Power
If edge-emitting semiconductor laser modules are used, then high power can be achieved, but the system complexity and volume increase due to non-planar arrangement and multiple micro-optical elements
Solution Approach 1:
The patent merges multiple VCSEL arrays into integrated lasing units that operate cooperatively. By combining the emission from multiple VCSELs within each lasing unit and using phase correctors to synchronize their output, the system achieves high power output while maintaining a simplified planar structure. This merging approach eliminates the need for complex individual optical elements for each VCSEL, reducing overall system complexity.
Solution Approach 2:
The patent replaces mechanical alignment systems with optical phase correction mechanisms. Instead of using complex mechanical positioning of micro-optical elements to achieve proper beam alignment, the system uses phase correctors to optically adjust the phase relationships between lasing units. This substitution of mechanical systems with optical control reduces moving parts and simplifies the overall system architecture.
3Power
If VCSEL arrays with large emitting area are used, then high power is achieved, but the area occupied by collimation lenses increases prohibitively
Solution Approach 1:
The patent segments the high-power laser system into multiple smaller lasing units, each with its own compact VCSEL array. By dividing the total power requirement across multiple segmented units rather than using a single large VCSEL array, the system achieves the same total power output while maintaining a much smaller overall footprint. Each segmented unit can be independently optimized for compactness.
Solution Approach 2:
The patent reorganizes the laser architecture from a vertically stacked configuration to a planar two-dimensional layout. This dimensional change allows the system to achieve high power output through lateral arrangement of multiple compact lasing units, significantly reducing the vertical space requirements and allowing for more efficient packaging and heat dissipation.
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 design achieves high optical power and brightness, enabling efficient fiber laser pumping with reduced system complexity, volume, weight, and cost, while maintaining coherence and minimizing side lobes.
Implementation Method 1
The optical phase correction elements are configured for manipulating light emitted by the at least some coherent lasing units so as to produce interference to output corrected beams
Implementation Method 2
a focusing optics assembly configured downstream of the one or more phase correctors for focusing the corrected beams into a focused beam
Data Source
AI summary
A fiber laser pump module comprising one or more lasing clusters comprising a plurality of lasing units disposed in a common plane. The lasing units are optically decoupled, such that light emitted by one lasing unit does not interfere with light of another lasing unit. The lasing units comprise at least some coherent lasing units, each coherent lasing unit includes a plurality of semiconductor surface-emitting laser elements that are mutually optically coupled, so that light emitted by one surface-emitting element interfere with light emitted by another surface-emitting element. Further included are one or more phase correctors for manipulating light emitted by the coherent lasing units to output corrected beams propagating in a single direction and having a far field pattern predominated by a single main lobe. A focusing optics assembly for focusing said corrected beams into a focused beam. An optical fiber for receiving and outputting the focused beam.