Wavelength Beam Combiner With Spatial Filtering Against Crosstalk
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Solution Overview
Problem
Traditional methods of wavelength beam combining in laser systems are susceptible to crosstalk between laser sources, leading to incorrect wavelength-locking and failure in combining beams into a single output, with existing solutions either introducing significant loss or failing to completely suppress crosstalk, potentially damaging the system.
Innovation Solution
A beam combiner system that spatially separates the combined beam into a locking beam for wavelength locking and an output beam, using a spatial filter to prevent crosstalk by ensuring only self-locking paths propagate, with a dispersive element like a grating and a partial reflector to direct the locking beam back to source elements for precise wavelength alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wavelength beam combining methods are used, then beam combination is achieved, but crosstalk between laser sources occurs leading to incorrect wavelength-locking
Solution Approach 1:
The patent segments the combined beam into two distinct paths: a locking beam path and an output beam path. The locking beam is spatially separated and directed through a spatial filter to prevent crosstalk, while the output beam maintains full power. This segmentation allows independent optimization of each path - the locking path for accuracy and the output path for power transmission.
Solution Approach 2:
The patent extracts a portion of the combined beam to form a dedicated locking beam that is spatially separated from the main output beam. This extracted locking beam passes through a spatial filter that removes crosstalk components, ensuring accurate wavelength-locking without affecting the main output beam quality or power.
2Reliability
If spatial filter is used to prevent crosstalk, then wavelength-locking accuracy improves, but significant loss is introduced to the output beam
Solution Approach 1:
The patent segments the combined beam into two separate paths before the spatial filter is applied. Only the locking beam portion (a small fraction of the total beam) passes through the spatial filter, while the main output beam bypasses the filter entirely. This ensures that the spatial filter's power loss affects only the locking path, not the main output beam.
Solution Approach 2:
The patent introduces a beam separator as an intermediary component that divides the combined beam into locking and output paths. This mediator allows the spatial filter to be inserted into only the locking beam path, preventing crosstalk filtering from affecting the main output beam while still achieving accurate wavelength-locking.
3Device complexity
If crosstalk is not completely suppressed, then system simplicity is maintained, but system damage may occur
Solution Approach 1:
The patent introduces a beam separator and spatial filter as intermediary components in the locking beam path. These intermediaries act as protective elements that prevent crosstalk from reaching the laser sources, thereby protecting the system from damage while maintaining overall structural simplicity through modular design.
Solution Approach 2:
The patent extracts and isolates the locking beam function from the main output beam, placing it in a separate path with dedicated crosstalk suppression components. This extraction allows for targeted protection against crosstalk without requiring complex modifications to the entire beam combining system.
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 solution effectively reduces or prevents crosstalk, ensuring accurate wavelength-locking of laser sources without adding significant loss to the output beam, enhancing the reliability and efficiency of the laser system for industrial materials processing applications.
Implementation Method 1
the dispersive element configured to disperse the locking beam into constituent wavelength beams
Implementation Method 2
a spatial filter configured to prevent crosstalk within the locking beam
Implementation Method 3
a beam separator configured to separate the combined beam exiting the dispersive element into an output beam and a locking beam
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A beam combiner (24) may include source elements (100), each configured to output a beam of light locked at a center wavelength different from center wavelengths of other source elements. The beam combiner may include a dispersive element like a transmission grating (102) configured to combine the beams of light into a combined beam, and a beam separator (103) configured to separate the combined beam into an output beam (109) and a locking beam (112) in the common branch (104) of the external resonator. The beam combiner includes a spatial filter configured to prevent crosstalk within the locking beam, and to redirect the locking beam to the source elements (100). The dispersive element may be configured to disperse the locking beam into constituent wavelength beams. Each constituent wavelength beam may be directed to a respective one of the source elements for locking that source element at its center wavelength, and may correspond in wavelength to the center wavelength of the respective source element. The spatial filter may comprise two lenses (105,107) building a telescope with an aperture (106) in the focal plane and a retro-reflector (108) for reflecting the laser beams back to the source elements (100).