Spectral Filter Array for Laser Alignment Diagnostics
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Solution Overview
Problem
Spectral beam combining (SBC) lasers face challenges in ensuring correct alignment and focus of individual laser sources, as existing methods are time-consuming and do not guarantee that adjustments to one source do not affect previously aligned sources.
Innovation Solution
A diagnostic unit comprising a spectral filter array and a microlens array, in conjunction with a sensor, is used to evaluate alignment, focus, and power of each laser source by filtering and focusing laser energy to provide real-time alignment and focus information, allowing for automated adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each beam is turned on separately and its output observed for alignment and focus, then alignment and focus can be evaluated, but the process becomes time-consuming
Solution Approach 1:
The patent segments the combined laser beam into individual wavelength components using a spectral filter array, where each filter corresponds to a specific laser source wavelength. This allows simultaneous evaluation of all laser sources without sequential switching, resolving the time-consuming nature of traditional diagnostic methods while maintaining precise alignment and focus measurement capability
Solution Approach 2:
The patent combines multiple diagnostic functions into a single integrated system that processes all laser wavelengths simultaneously. By merging the spectral filtering, focusing, and detection functions into one diagnostic unit, the system achieves comprehensive alignment and focus evaluation of all laser sources in a single operation, eliminating the time loss associated with sequential measurement
2Manufacturing precision
If adjustments are made to laser sources, then alignment can be improved, but mechanical or other changes may occur to previously adjusted laser sources
Solution Approach 1:
The patent implements a feedback mechanism where the diagnostic unit continuously monitors the alignment and focus of all laser sources simultaneously. The sensor array provides real-time feedback on the position and quality of each beam, allowing for closed-loop control that can detect and correct alignment drift or mechanical changes in previously adjusted sources, thereby maintaining alignment stability
Solution Approach 2:
The patent enables preliminary diagnostic evaluation of all laser sources before final alignment is established. By using the spectral filter array and sensor system to pre-assess the alignment and focus of each source, adjustments can be made with confidence that other sources remain properly aligned, reducing the likelihood of cascading alignment issues
3Loss of information
If a diagnostic system is added to evaluate each laser source, then alignment and focus information can be obtained, but the device complexity increases
Solution Approach 1:
The patent designs a universal diagnostic unit that can evaluate all laser sources across different wavelengths using a standardized configuration of spectral filters, microlenses, and sensors. This multi-functional system handles multiple wavelengths and diagnostic functions through a single integrated architecture, reducing overall device complexity compared to having separate diagnostic systems for each wavelength
Solution Approach 2:
The patent introduces a spectral filter array as an intermediary element that cleanly separates the combined laser beam into individual wavelength components. Each filter-microlens-sensor triplet acts as an independent intermediary channel that processes one wavelength without interfering with others, simplifying the diagnostic architecture while enabling comprehensive information gathering
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 diagnostic unit enables efficient and accurate alignment and focus of SBC lasers, ensuring optimal power output by providing real-time feedback and enabling automated corrections, thereby improving the setup and maintenance efficiency of SBC lasers.
Implementation Method 1
a spectral filter array arranged to accept laser output of the SBC laser that includes one or more spectral filters for at least one wavelength present in the SBC laser
Implementation Method 2
a microlens array including at least one microlens for the particular wavelength present in the SBC laser
Implementation Method 3
a sensor aligned with the microlens array and the spectral filter so that the laser energy passing through the at least one spectral filter and the at least one microlens activates a portion of the sensor
Data Source
AI summary
A diagnostic unit is used to align and focus individual laser sources in a spectral beam combining (SBC) laser. The diagnostic unit modifies a Shack-Hartmann wavefront sensor to dedicate one or more microlenses to a particular wavelength of the SBC laser using wavelength-specific filters in combination with corresponding microlenses. The diagnostic unit allows all of the laser sources to be evaluated at the same time because each wavelength has a dedicated portion of the sensor, typically a charge-coupled display. When an individual beam is centered in its dedicated portion of the sensor and has an acceptable spot size or intensity, the source for that particular beam is correctly aligned and focused. Off-center or incorrect spot-sized beams indicate incorrect alignment and focus for the laser source for that wavelength. When correctly calibrated, the sensor output can also be used to measure and correct power output levels of the individual laser sources.