Laser Light-Source Apparatus Thermal Management During Output Stops
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Solution Overview
Problem
Laser light-source apparatuses face challenges in temporarily stopping and resuming pulse light output, leading to excessive energy accumulation and thermal issues that damage solid state amplifiers and affect processing quality due to fluctuations in excitation light power and thermal lens effects.
Innovation Solution
A control unit manages the seed light source to switch between pulse and continuous oscillation modes, maintaining excitation light power and adjusting input power to solid state amplifiers to maintain stable thermal and amplification characteristics, preventing damage and degradation during output stops and resumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the output of pulse light is temporarily stopped during processing, then the processing can be paused, but excessive energy accumulates in the solid state amplifier causing damage or degradation of beam propagation characteristics
Solution Approach 1:
The patent applies preliminary action by switching the seed light source to continuous oscillation mode before temporarily stopping the pulse light output. This continuous light consumption prevents excessive energy accumulation in the solid state amplifier's active region, thereby preventing damage or degradation when the output is resumed. The system prepares the amplifier in advance by maintaining light propagation during output pauses.
Solution Approach 2:
The patent uses continuous light from the seed light source as an intermediary to consume excess energy in the solid state amplifier during temporary output stops. This continuous light acts as a mediator that transfers the accumulated energy from the amplifier's active region, preventing giant pulse formation and damage while allowing the amplifier to remain in a safe state during pauses.
2Reliability
If the excitation light power is reduced to prevent energy accumulation, then amplifier damage is prevented, but thermal lens effects and beam propagation degradation occur due to temperature fluctuations
Solution Approach 1:
The patent applies preliminary action by maintaining the excitation light power at its normal level even during temporary output stops. By switching the seed light source to continuous oscillation mode, the system proactively consumes excess energy in the amplifier, eliminating the need to reduce excitation power and thereby preventing thermal lens effects and beam propagation degradation.
3Reliability
If the seed light source is stopped to prevent energy accumulation, then amplifier damage is prevented, but giant pulses are generated when oscillation resumes causing damage to optical components
Solution Approach 1:
The patent applies preliminary action by switching the seed light source to continuous oscillation mode before temporarily stopping pulse light output. This continuous light consumption prevents excessive population inversion in the amplifier's active region, thereby preventing giant pulse formation when oscillation resumes. The system prepares the amplifier in advance by maintaining light propagation during output pauses.
Solution Approach 2:
The patent uses periodic switching between pulse oscillation mode and continuous oscillation mode of the seed light source. During temporary output stops, the system switches to continuous mode to consume excess energy, then returns to pulse mode when output is resumed. This periodic action pattern prevents energy accumulation and giant pulse generation while maintaining amplifier safety.
4Ease of operation
If mode-locked laser is used as seed light source, then pulse light with controllable frequency can be obtained, but complex synchronization circuits are required and long term stable driving is difficult
Solution Approach 1:
The patent extracts and eliminates the complex synchronization circuitry required by mode-locked lasers by using a semiconductor laser with gain switching instead. The invention removes the problematic saturable absorber and frequency division synchronization components, keeping only the essential gain switching mechanism in the semiconductor laser to achieve controllable pulse frequency without complex external circuits.
Solution Approach 2:
The patent makes the semiconductor laser self-sufficient by using gain switching directly within the laser structure to control pulse frequency and timing. The laser automatically generates controllable pulse frequency through its intrinsic gain characteristics without requiring external synchronization circuits or frequency division, enabling long term stable driving through self-service operation.
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 approach prevents damage to solid state amplifiers and maintains stable beam propagation characteristics and processing accuracy by consuming excess energy and maintaining a stable thermal state during output stops and resumes, ensuring consistent pulse light quality.
Implementation Method 1
an optical amplifier that amplifies the laser light output from the seed light source
Implementation Method 2
a nonlinear optical element that converts the wavelength of the laser light, amplified by the optical amplifier, into a target wavelength
Implementation Method 3
both require an excitation light source for amplifying light with the same wavelength as laser light amplified by a pumping effect in a laser active region
Data Source
AI summary
A laser light-source apparatus includes a control unit configured to perform control in such a manner that a seed light source is driven in a pulse oscillation mode of oscillating pulse light based on gain switching in an output permitted state where output of pulse light from the apparatus is permitted, and is driven in a continuous oscillation mode of oscillating continuous light in an output stopped state in which the output of the pulse light from the apparatus is stopped, with power of excitation light for a solid state amplifier maintained, and adjusts power of laser light input to the solid state amplifier from the seed light source in the continuous oscillation mode in such a manner that the solid state amplifier outputs light with substantially same average power in the output stopped state and in the output permitted state.