Sealed Dual-Grating SBC Assembly for Stable Beam Combining
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Solution Overview
Problem
High Energy Laser (HEL) Spectral Beam Combining (SBC) systems face challenges with grating contamination, wavelength dispersion degrading beam quality, and the need for precise alignment of multiple gratings, which complicates system maintenance and operation, especially during shipment and field service.
Innovation Solution
A dual-grating fiber SBC system with transmissive gratings protected by a micro-vented tube and modular design, using fused silica components with aligned datums for stable alignment, allowing field serviceability and protection from contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single grating is used in the SBC system, then the system complexity is reduced, but wavelength dispersion degrades beam quality
Solution Approach 1:
The patent combines two gratings into a single integrated component where the first grating disperses wavelengths and the second grating recombines them, merging the dispersion and recombination functions into one unified optical element that maintains beam quality while simplifying the overall system architecture
2Manufacturing precision
If two matched gratings are used for dispersion compensation, then beam quality is improved, but alignment precision requirements increase
Solution Approach 1:
The patent incorporates alignment features and mounting structures directly into the grating component design during manufacturing, pre-establishing precise geometric relationships between the first and second gratings so that alignment is achieved through the built-in features rather than requiring post-assembly adjustment
3Device complexity
If the grating is exposed to the environment during operation, then system complexity is reduced, but contamination from airborne particles increases
Solution Approach 1:
The patent uses a transparent protective window or cover that acts as a barrier between the grating and the environment, allowing laser light to pass through while blocking airborne particles and contaminants, thus protecting the grating without requiring complex sealed enclosures
4Object-affected harmful factors
If HEPA filters and dry air purging are used to protect gratings, then grating cleanliness is improved, but system complexity and operational cost increase
Solution Approach 1:
The patent extracts the grating from the sensitive environmental control system by designing the grating with inherent contamination resistance through protective coatings and robust mounting, allowing the grating to operate in less controlled environments without requiring HEPA filters and dry air purging infrastructure
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
Maintains beam quality and alignment stability under varying environmental conditions, enabling field service and reducing complexity in system maintenance, while using less expensive laser sources and minimizing operational disruptions.
Implementation Method 1
a first transmissive diffraction grating 70a configured to receive a set of incident beams 14 and transmit a set of diffracted beams 16
Implementation Method 2
a second transmissive diffraction grating 70b configured to receive the set of diffracted beams 16 and transmit a combined beam 18
Data Source
AI summary
An apparatus is used for spectral beam combining laser wavelengths into a combined beam. The apparatus has an integrated, sealed optical assembly that can be installed and replaced in the field. The optical assembly has a housing composed of a material, such as fused silica, transparent to the laser wavelengths. Transmissive gratings are disposed on ends of the housing and have their datums facing the sealed interior. V-grooves on a shelf at one end of the housing are disposed at an angle relative to the first grating. Fiber ends of a fiber array have end caps affixed in the V-grooves and aligned to the datums of the first grating. The fiber ends transmit the laser wavelengths in an array of beams toward the first grating, which diffracts the laser wavelengths to the second grating. In turn, the second grating transmits the laser wavelengths as a combined beam from the second end of the housing.