Wavelength Combining Laser Arrays via Diffraction Grating
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Solution Overview
Problem
Current methods for generating high power, high brightness laser beams are limited by nonlinear effects and thermal dissipation issues in single optical fibers, and combining multiple fiber lasers is constrained by physical space and phase control requirements.
Innovation Solution
The technique involves combining multiple laser beams using a dispersive element like a diffraction grating, allowing for the superposition of up to four arrays of lasers operating at different wavelengths to produce a single, more powerful beam with improved energy efficiency and reduced sensitivity to phase and optical path differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple fiber lasers are combined to increase power, then the total power output increases, but the system complexity and phase control requirements increase significantly
Solution Approach 1:
The patent replaces the mechanical/optical phase control system with a wavelength-based combining system. Instead of using complex phase modulation hardware and precision mechanical alignment, the invention uses wavelength-division multiplexing where each laser operates at a distinct wavelength that is automatically combined by the optical fiber amplifier, eliminating the need for complex phase control mechanisms
Solution Approach 2:
The patent changes the operating parameter from phase control to wavelength control. Each laser in the array operates at a slightly different wavelength, and the combination is achieved through wavelength-selective amplification in the optical fiber, transforming the control paradigm from temporal phase synchronization to spectral wavelength differentiation
2Power
If the number of combined lasers is increased to maximize power, then the power output increases, but physical space requirements and thermal dissipation challenges increase
Solution Approach 1:
The patent merges multiple individual laser beams into a single combined beam that propagates through a single optical fiber amplifier. This consolidation allows the thermal energy from multiple lasers to be managed within a single fiber structure, improving thermal dissipation efficiency while maintaining high total power output
Solution Approach 2:
The patent utilizes the porous or multi-core structure of optical fibers to accommodate multiple laser modes or wavelengths simultaneously. The fiber's internal structure provides multiple propagation paths or modes that can handle multiple input beams, effectively managing the thermal load distribution while maintaining compact form factor
3Device complexity
If lasers operate at different wavelengths to simplify combining, then phase control complexity decreases, but wavelength control precision requirements increase
Solution Approach 1:
The patent implements a self-aligning wavelength combination system where the optical fiber amplifier automatically selects and amplifies the specific wavelengths from the laser array based on its gain spectrum characteristics. The system self-regulates the wavelength selection without requiring external precision control mechanisms, as the fiber's physical properties determine which wavelengths are amplified
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 increases the power of the combined laser beam while maintaining beam quality, is less sensitive to environmental noise, and avoids the complexity of phase control, enabling applications in material processing, medical procedures, and other high-power uses.
Implementation Method 1
combining multiple laser beams using a dispersive element like a diffraction grating
Data Source
AI summary
Light beams from multiple emitters, such as lasers, arranged in two or more arrays are combined by beam-superposition using a dispersive element, such as a diffraction grating, to provide a combined output beam with increased power. Each emitter produces light of a controlled wavelength that is incident upon the diffraction grating at a corresponding selected incidence angle to produce a diffracted wave that propagates in an output direction and forms a component of the combined output beam. First and second arrays are located on opposing sides of the combined output beam and are arranged such that light from all of the emitters overlaps to form the combined output beam. The wavelengths may be controlled by an external resonator, for example. As many as four arrays may be combined using a two-dimensional diffraction grating.