Stepped Laser Minibar WBC Layout for Beam Quality and Thermal Control
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Solution Overview
Problem
Current optical modules using wavelength beam combining (WBC) for laser minibars face limitations in achieving high-power, high-brightness laser beams due to constraints in beam parameter product (BPP) and thermal management, which affect efficient fiber coupling and overall module performance.
Innovation Solution
The optical module employs a stepped structure with distributed laser minibars, fast axis collimators, slow axis collimators, and gratings, where each laser minibar is positioned at a unique step with specific distances from the output coupler, allowing for slow axis WBC and spatial beam combination, while the stepped structure acts as a heatsink to manage heat and enhance thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple laser beams are combined using wavelength beam combining (WBC), then the power and brightness of the laser beam are improved, but the beam parameter product (BPP) constraints and thermal management challenges worsen
Solution Approach 1:
The patent divides the laser source into multiple separate laser bars, each emitting at a different wavelength. These segmented laser bars are then combined using WBC technology, allowing independent thermal management for each bar while achieving high total power output. The segmentation enables better heat dissipation control compared to a single high-power laser source.
Solution Approach 2:
The patent implements a nested structure where multiple laser bars are integrated within a compact optical module housing. The laser bars, collimation optics, and WBC components are arranged in a nested configuration that maximizes space utilization while maintaining thermal pathways. This nested arrangement allows high power density without proportionally increasing the module's external dimensions.
2Volume of moving object
If laser bars are positioned closer to achieve compact design, then the device size is reduced, but the beam quality and fiber coupling efficiency deteriorate
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement of laser bars at different positions and angles relative to the WBC optics. By arranging laser bars in multiple dimensions rather than a simple linear configuration, the design achieves compact footprint while maintaining optimal beam propagation paths. The vertical and lateral positioning of laser bars allows independent optimization of beam quality and module compactness.
3Power
If more laser beams are combined to increase power output, then the power increases, but the thermal management difficulty and system complexity increase
Solution Approach 1:
The patent employs a universal thermal management architecture where multiple laser bars share common heat sinking structures and cooling pathways. The optical module integrates thermal conduction paths that collect heat from multiple laser sources and channel them through shared heat sinks, reducing the overall thermal management complexity compared to independent cooling systems for each laser bar.
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 power and brightness of the laser beams by improving beam quality and thermal management, leading to increased reliability and efficiency in coupling more laser beams into a fiber, thus improving the dollar per watt performance of the optical module.
Implementation Method 1
Wavelength beam combining (WBC) is a technique that combines multiple laser beams (e.g., of different wavelengths) into a single laser beam
Implementation Method 2
a plurality of gratings are configured to receive the plurality of laser beams via the plurality of FACs and the plurality of SACs, to combine the plurality of laser beams into a plurality of single laser beams
Implementation Method 3
the stepped structure acts as a heatsink to manage heat and enhance thermal conductivity
Implementation Method 4
each FAC, of the plurality of FACs, corresponds to a laser minibar, of the plurality of laser minibars, and is disposed between the laser minibar and a SAC, of the plurality of SACs, that corresponds to the laser minibar
Data Source
AI summary
An optical module includes a stepped structure; a plurality of laser minibars; a plurality of FACs; a plurality of SACs; a plurality of gratings; and an OC. At least one laser minibar, of the plurality of laser minibars, is disposed on each step of the plurality of steps of the stepped structure. The plurality of laser minibars are configured to emit a plurality of laser beams. The plurality of gratings are configured to receive the plurality of laser beams via the plurality of FACs and the plurality of SACs, to combine the plurality of laser beams into a plurality of single laser beams, and to direct the plurality of single laser beams to the OC. The OC is configured to receive the plurality of single laser beams from the plurality of gratings, and to direct a portion of the plurality of single laser beams out of the optical module.