Phased-Array Beam Steering for GHz Laser Micromachining
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Solution Overview
Problem
Existing laser-micromachining processes face challenges with spatially overlapping pulses leading to negative effects like local heat accumulation and pulse-plume interaction, necessitating beam steering systems with higher positioning bandwidths than what acousto-optic deflectors and polygon mirrors can provide.
Innovation Solution
A phased-array beam steering system using a photonic integrated circuit (PIC) with amplitude and phase modulators, coupled with an optical amplifier and feedback system, enables high-bandwidth beam steering and shaping, allowing for precise control of laser pulses at GHz rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If acousto-optic deflectors (AODs) are used for beam steering, then positioning bandwidth is improved (~1 MHz), but the bandwidth is insufficient for high repetition rate lasers (1 MHz - 100 MHz and higher)
Solution Approach 1:
The patent replaces traditional mechanical beam steering systems (galvos, polygon mirrors) and acousto-optic deflectors with a photonic integrated circuit-based phased array system. This substitution enables electronic control of beam steering at GHz rates, matching the repetition rates of modern high-powered lasers and eliminating the bandwidth bottleneck that limited laser utilization.
Solution Approach 2:
The patent changes the operating parameters of beam steering from kHz-range mechanical/AOD systems to GHz-range photonic systems. By using photonic integrated circuits with phase modulators operating at GHz frequencies, the system achieves positioning bandwidths that match or exceed the repetition rates of high-powered lasers, enabling efficient utilization of these sources.
2Speed
If polygon mirrors are used for beam steering, then positioning bandwidth is improved (>> 1 MHz), but the system is limited to high fill factor problems and lacks accuracy for smaller features
Solution Approach 1:
The patent divides the beam steering function into multiple independent phase modulators arranged in a phased array on a photonic integrated circuit. This segmentation allows precise electronic control of beam position and enables arbitrary beam shaping, providing both high speed and high precision for small feature fabrication that polygon mirrors cannot achieve.
Solution Approach 2:
The patent replaces mechanical polygon mirror systems with a photonic integrated circuit-based phased array. This substitution eliminates the mechanical limitations and fill-factor constraints of polygon mirrors, enabling precise positioning for small features while maintaining GHz-range bandwidth through electronic phase control.
3Device complexity
If galvos are used for beam steering, then system complexity is reduced, but positioning bandwidth is limited (~2.5 kHz)
Solution Approach 1:
The patent replaces mechanical galvo systems with a photonic integrated circuit-based phased array. While the PIC system is more complex in fabrication, it eliminates mechanical moving parts, achieving GHz-range positioning bandwidth through electronic phase modulation. The integration of multiple phase modulators on a single chip provides both high speed and system compactness.
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 system achieves stable and precise beam steering and shaping, enabling efficient processing of materials with high repetition rates and accuracy, overcoming limitations of current technologies.
Implementation Method 1
A phased-array beam steering system using a photonic integrated circuit (PIC) with amplitude and phase modulators
Implementation Method 2
photonic integrated circuit (PIC) with amplitude and phase modulators
Implementation Method 3
coupled with an optical amplifier and feedback system
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A system includes a multi-channel beam splitter arranged and configured to split an input optical signal into a plurality of split optical signals; a plurality of phase modulators, wherein each phase modulator of the plurality of phase modulators is operative to modify a phase of a corresponding split optical signal of the plurality of split optical signals in response to a control signal; a waveguide arranged at an optical output of the plurality of phase modulators, the waveguide configured to spatially-rearrange the split optical signals output from the plurality of phase modulators into a pattern, thereby producing an optical signal pattern; and an optical amplifier arranged at an optical output of the waveguide, wherein the optical amplifier is configured to amplify the optical signal pattern produced by the waveguide.