Fiber Laser Pre-Pumping Control for Rise Time and Oscillation
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Solution Overview
Problem
Fiber laser devices face issues with unnecessary high-intensity light emission during non-emission periods, leading to potential damage to processed objects due to high crest value light, and require a balance in rise time and oscillation prevention.
Innovation Solution
A fiber laser device with a control unit managing seed and pumping light sources, implementing pre-pumping with a predetermined intensity before emission, and utilizing a wavelength converter and optical filter to suppress unnecessary light emission, while optimizing the intensity and duration of light exposure to prevent oscillation and shorten rise time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-pumping is performed with high intensity pumping light during non-emission periods, then the rise time of laser light is shortened, but oscillation occurs and unnecessary light with high crest value is emitted
Solution Approach 1:
The patent applies preliminary action by performing pre-pumping with pumping light during non-emission periods to prepare the rare-earth element in the amplification optical fiber before laser light emission. This reduces the rise time when laser light is actually emitted. The control unit manages the timing to ensure pre-pumping occurs only during safe intervals, preparing the system in advance for efficient operation.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the intensity and timing of pumping light based on the emission state. The control unit varies the pumping light intensity between high during pre-pumping periods and adjusted during emission periods, creating a dynamic control system that adapts to different operational phases to prevent oscillation while maintaining short rise time.
2Use of energy by moving object
If pumping light with high intensity is incident on the amplification optical fiber during non-emission periods, then the pumped state of rare-earth element is enhanced, but oscillation occurs in the resonator
Solution Approach 1:
The patent applies feedback by using the control unit to monitor and adjust the pumping light intensity based on the emission state. The control unit receives emission state information and adjusts pumping light intensity accordingly, creating a feedback loop that prevents oscillation by reducing pumping intensity when the resonator gain approaches positive values, while still maintaining effective pre-pumping during non-emission periods.
Solution Approach 2:
The patent implements parameter changes by varying the intensity parameter of pumping light based on operational phase. The control unit changes the pumping light intensity from high during pre-pumping to adjusted levels during emission, and sets it to zero during emission periods. This parameter modulation prevents oscillation while maintaining effective rare-earth element pumping.
3Productivity
If the period of pre-pumping is extended to further shorten rise time, then laser light emission becomes faster, but unnecessary light emission with high crest value increases
Solution Approach 1:
The patent applies periodic action by implementing cyclic pre-pumping during non-emission periods followed by emission periods. The control unit manages periodic switching between pre-pumping and emission states, with the pre-pumping duration optimized to be sufficient for shortening rise time but limited to prevent oscillation. This periodic control pattern balances productivity improvement with harm prevention.
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 suppresses unnecessary high-intensity light emission during non-emission periods, shortens the rise time of laser light, and prevents oscillation by balancing the pumping and seed light intensities and states, ensuring efficient and safe operation.
Implementation Method 1
an amplification optical fiber that receives the seed laser light and the pumping light, amplifies the seed laser light, and emits laser light, the amplification optical fiber being doped with a rare-earth element to be pumped by the pumping light
Implementation Method 2
pumping light with a predetermined intensity is incident on the amplification optical fiber
Data Source
AI summary
In a case where the period from the input of the output suspension instruction to the next output instruction is shorter than the fixed period of time, the seed laser light source and the pumping light source are in a pre-pumped state during the period from the end of the output state to the start of the next output state. In a case where the period from the input of the output suspension instruction to the next output instruction is longer than the fixed period of time, the seed laser light source and the pumping light source are in the pre-pumped state only for the fixed period of time from the input of the output instruction.