Laser Light-Source Apparatus with Optical Switching for Pulse Control

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Solution Overview

Problem

Laser light-source apparatuses face challenges in temporarily stopping pulse light output without damaging solid state amplifiers and nonlinear optical elements, leading to degraded beam propagation characteristics due to excessive energy accumulation and heat generation.

Innovation Solution

The apparatus employs an optical switching element controlled by a unit that stops light propagation to the solid state amplifier during pulse light output cessation, allowing spontaneous emission noise to discharge and preventing giant pulse generation, thus maintaining beam quality upon resumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the output of pulse light is temporarily stopped while the seed light source is driven, then the processing work can be paused, but excessive energy accumulation occurs in the solid state amplifier leading to damage risk and degraded beam propagation characteristics

Engineering Contradiction:
ImproveAbility to pause outputVSAvoidDamage risk to solid state amplifier
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

An optical switching element is introduced as an intermediary component between the fiber amplifier and solid state amplifier. This switching element can be rapidly activated to block the optical path, preventing excessive energy from reaching the solid state amplifier when pulse light output is paused, thereby protecting the amplifier while allowing the seed light source to continue operating

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical switching element is positioned upstream in the optical path to preemptively block excessive energy before it can accumulate and damage the solid state amplifier. By placing the switching element at this location, the system can quickly interrupt energy flow in advance, preventing the harmful effect of excessive energy accumulation before it occurs

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the excitation light source is stopped to prevent energy accumulation, then damage to components is prevented, but the system cannot quickly resume operation without重新启动 the entire system

Engineering Contradiction:
ImproveProtection from damageVSAvoidResumption speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system is segmented into independent components: the seed light source, excitation light source, and optical switching element can be controlled separately. This allows the optical switching element to be rapidly activated to protect the solid state amplifier while the seed light source and excitation light source remain operational, enabling quick resumption of pulse light output without restarting the entire system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical switching element provides dynamic control over the optical path, allowing rapid switching between blocked and open states. This dynamic capability enables the system to quickly respond to pausing requirements and resume operation by simply changing the switching element's state, rather than requiring system-wide restart procedures

Inventive Principle:
Principle #15Dynamics

3Power

If conventional seed light sources like mode-locked lasers are used, then pulse light with large peak power can be obtained, but the oscillating frequency fluctuates due to environmental factors requiring complex synchronization circuits

Engineering Contradiction:
ImprovePeak power of pulse lightVSAvoidSynchronization circuit complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The invention changes the fundamental parameter of frequency stability by replacing the mode-locked laser with a semiconductor laser that inherently provides stable, controllable oscillation frequency. This parameter change eliminates the need for complex synchronization circuits while maintaining the capability to generate high peak power pulse light through the amplification process

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If semiconductor laser is used as seed light source for controllable frequency, then frequency can be controlled, but pulse energy is extremely small requiring much stronger amplification

Engineering Contradiction:
ImproveFrequency controllabilityVSAvoidAmplification energy requirement
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The invention merges two amplification stages: a fiber amplifier for initial amplification of the semiconductor laser output, and a solid state amplifier for final high-energy pulse generation. This combined amplification approach efficiently bridges the energy gap between the low-energy semiconductor laser input and the high-energy pulse light output, making the system both controllable and energy-efficient

Inventive Principle:
Principle #5Merging (Combining)

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

Prevents damage to solid state amplifiers and nonlinear optical elements, ensuring stable beam propagation characteristics after output resumption without stopping the excitation light source.

Implementation Method 1

an optical amplifier that amplifies the laser light output from the seed light source

Methodology Applied
Scientific EffectPumping effect:

Implementation Method 2

a nonlinear optical element that converts the wavelength of the laser light, amplified by the optical amplifier, into a target wavelength

Methodology Applied
Scientific EffectNonlinear optical conversion:

Data Source

PatentEP3131163B1Laser light-source apparatus and laser pulse light generating method
Publication Date: 2021.09.22 SPECTRONIX CORP
  • EP3131163B1 patent drawingFigure 1
  • EP3131163B1 patent drawingFigure 2A~2C
  • EP3131163B1 patent drawingFigure 3A~3F

AI summary

A laser light-source apparatus includes: fiber amplifiers and a solid state amplifier configured to amplify pulse light output from a seed light source based on gain switching; nonlinear optical elements configured to perform wavelength conversion on the pulse light output from the solid state amplifier; an optical switching element configured to permit or stop propagation of pulse light from the fiber amplifier to the solid state amplifier; and a control unit configured to control the optical switching element in such a manner that the propagation of the light is stopped in an output period of the pulse light from the seed light source, and permitted in a period other than the output period of the pulse light from the seed light source.