Wavelength Beam Combining Laser Cross-Coupling Mitigation
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Solution Overview
Problem
Conventional wavelength beam combining (WBC) laser systems suffer from sub-optimal brightness due to optical cross-coupling between beam emitters, which degrades the quality and efficiency of the laser output.
Innovation Solution
The implementation of a non-slit-based cross-coupling mitigation system, utilizing optical elements with differing focal lengths and strategically positioning the output coupler within the Rayleigh range of the multi-wavelength beam, along with engineered output couplers that minimize back-reflection and incorporate anti-reflection coatings, to reduce cross-coupling and enhance beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional WBC systems use common partially reflecting output coupler without cross-coupling mitigation, then device complexity is reduced, but optical cross-coupling between beam emitters degrades beam quality and brightness
Solution Approach 1:
The patent introduces a non-slit-based cross-coupling mitigating optical system as an intermediary component between the beam emitters and the output coupler. This optical system selectively blocks cross-coupling light paths while allowing desired laser beams to pass through, thereby improving beam quality without requiring fundamental changes to the WBC system architecture.
Solution Approach 2:
The output coupler is engineered with spatially varying properties: a central region with specific reflectivity for wavelength selection and an outer region with anti-reflection coating to minimize stray reflections. This local differentiation of optical properties allows the single output coupler to simultaneously perform wavelength stabilization and cross-coupling mitigation functions.
2Ease of operation
If output coupler is positioned outside the Rayleigh range, then alignment is simplified, but cross-coupling mitigation effectiveness is reduced
Solution Approach 1:
The patent positions the output coupler within the Rayleigh range of the multi-wavelength beam, utilizing the specific optical field distribution characteristics at this distance. The non-slit-based optical system is configured with specific focal lengths and spacing to exploit the Rayleigh range geometry for maximizing cross-coupling rejection while maintaining practical alignment tolerances.
3Ease of manufacture
If standard output coupler is used without anti-reflection coating, then manufacturing is simpler, but stray reflections increase cross-talk between emitters
Solution Approach 1:
The output coupler is engineered with spatially varying properties: a central region with specific reflectivity for wavelength selection and an outer region with anti-reflection coating to minimize stray reflections. This local differentiation of optical properties allows the single output coupler to simultaneously perform wavelength stabilization and cross-coupling mitigation functions.
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 approach results in high-brightness, high-power multi-wavelength output beams by minimizing cross-talk and stray reflections, thereby improving the overall performance of the laser system.
Implementation Method 1
a dispersive element for receiving and dispersing the focused beams, thereby forming a multi-wavelength beam
Implementation Method 2
positioning the output coupler within the Rayleigh range of the multi-wavelength beam
Implementation Method 3
engineered output couplers that minimize back-reflection and incorporate anti-reflection coatings
Data Source
AI summary
In various embodiments, wavelength beam combining laser systems incorporate optical cross-coupling mitigation systems and/or engineered partially reflective output couplers in order to reduce or substantially eliminate unwanted back-reflection of stray light.