Laser Pulse Power Stabilization via Feedback Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser processing devices face challenges in stabilizing the power of laser pulses, leading to inconsistent processing quality due to variations in pulse power, particularly during the transition from preliminary to main emission periods in MOPA systems.
Innovation Solution
A light amplifier system that includes a light amplifying fiber, a seed light source, an excitation light source, a detector, and a control unit to adjust the power of the exciting light based on detected output pulse power, ensuring that initial and final output pulses have consistent power levels by modifying the bias current of the semiconductor laser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fiber laser is used to set pulse conditions independently, then pulse repetition frequency, pulse width, and pulse power can be controlled independently, but the optimal output value of the low powered laser beam may not match these conditions, causing first pulses to have different strength from stabilized pulses
Solution Approach 1:
The patent implements a feedback control mechanism where a detector measures the power of laser pulses and feeds this information back to a control unit. The control unit adjusts the excitation light power based on the detected pulse power to maintain consistent output. This closed-loop feedback system resolves the contradiction by dynamically adapting the laser parameters to ensure consistent pulse strength while maintaining independent control capability.
Solution Approach 2:
The patent applies preliminary action by adjusting the excitation light power during a preliminary radiation period before the main radiation period. This preliminary adjustment ensures that the fiber laser reaches an optimal excited state before actual processing begins, allowing the first pulses to have consistent strength with subsequent stabilized pulses rather than experiencing a transition period.
2Power
If feedback control using average power is implemented, then average power can be controlled, but control for each individual pulse cannot be performed
Solution Approach 1:
The patent enhances the feedback mechanism to provide both average power control and per-pulse control. The detector measures each individual pulse's power, and the control unit adjusts excitation light power for each pulse based on real-time detection. This allows simultaneous achievement of average power control and individual pulse control, resolving the contradiction between these two control modes.
3Loss of energy
If amplified light is emitted during preliminary radiation period, then optical fiber can prevent energy accumulation, but configuration for ensuring control on pulse power is not specifically disclosed
Solution Approach 1:
The patent implements a specific feedback control configuration where the detector monitors pulse power and the control unit adjusts excitation light power accordingly. This well-defined feedback mechanism provides explicit control over pulse power during the preliminary radiation period, preventing excessive energy accumulation while maintaining manageable device complexity through a standardized control approach.
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 solution stabilizes the laser pulse output from the first pulse, enhancing processing quality by maintaining consistent pulse power through feedback-controlled adjustments, thereby reducing variations and improving the overall performance of the laser processing device.
Implementation Method 1
a light amplifying fiber (1) for amplifying seed light by excitation light
Implementation Method 2
amplifying seed light by exciting light
Implementation Method 3
an excitation light source (3) for generating the exciting light
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light amplifier which is capable of stably outputting laser pulses from the first pulse and a laser processing device are provided. A laser processing device 100 includes a light amplifying fiber 1, a seed LD 2 for pulsing seed light for plural times during an emission period, an excitation LD 3 for generating the exciting light of power at a first level during a non-emission period which is immediately before the emission period and generating the exciting light of power at a second level which is higher than the first level during the emission period, a light receiving element 15 and a peak value detector 16 for detecting power of an output light pulse which is output from the light amplifying fiber, and a control device 20. The control device 20 controls the power (a bias current of a driver 22) of the exciting light of the non-emission period based on the detected value from the peak value detector to cause the power of first output light pulses which are generated during the emission period to be the same as the power of final output light pulses.