Fiber-Based Optical Pulse Amplifier for High Peak Power

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Solution Overview

Problem

Optical pulse amplifiers face challenges in achieving high peak and average power while maintaining a high repetition rate due to cooling difficulties and inefficiencies, particularly with bulk amplifiers having a high surface-to-volume ratio, which limits their performance in generating high-energy pulses.

Innovation Solution

The use of a fiber-based optical pulse amplifier system with a stretcher, multiple optical fiber amplifiers, and compressors to generate coherent output pulses, allowing for increased peak power and efficient cooling, enabling higher repetition rates and improved efficiency through the use of a fiber bundle and identical optical fiber amplifiers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the size of the bulk is increased to increase the energy of the signal generated by the amplifier, then the energy of the signal is improved, but the repetition rate of the amplifier decreases

Engineering Contradiction:
Improveenergy of the signalVSAvoidrepetition rate
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The invention divides the bulk amplifier into multiple separate optical fiber amplifiers. Each fiber amplifier processes a portion of the signal, and their outputs are combined to achieve the desired total energy. This segmentation allows each fiber to be efficiently cooled while collectively delivering high energy output at high repetition rates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces the bulk solid-state amplifier with optical fiber amplifiers. This substitution fundamentally changes the thermal management approach, as fibers can be efficiently cooled through their large surface area to volume ratio, enabling high repetition rates while maintaining signal energy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If bulk amplifiers are used to generate high energy pulses, then the energy output is improved, but the cooling difficulty increases due to high surface-to-volume ratio

Engineering Contradiction:
Improveenergy outputVSAvoidcooling difficulty
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The invention replaces bulk amplifiers with optical fiber amplifiers. The fiber geometry provides a vastly improved surface area to volume ratio compared to bulk materials, enabling efficient heat dissipation through the fiber cladding. This allows continuous high-energy operation at high repetition rates without thermal management issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If typical laser efficiency is used to produce high average power, then the power output is improved, but the energy efficiency deteriorates

Engineering Contradiction:
Improveaverage powerVSAvoidenergy efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The invention replaces bulk laser amplifiers with optical fiber amplifiers, which offer superior pump-to-signal conversion efficiency. The fiber geometry enables more effective pumping and reduced threshold effects, achieving typical efficiencies exceeding 50% compared to the 1% efficiency of conventional bulk systems. This allows high average power output with minimal energy waste.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 allows for the generation of high peak and average power with increased repetition rates and improved efficiency, as the fiber-based system can be easily cooled and efficiently powered, overcoming the limitations of bulk amplifiers.

Implementation Method 1

a first optical fiber amplifier adapted to receive said input pulse; a plurality of optical fiber amplifiers, each being connected to one of said plurality of outputs for generating a plurality of output pulse signals

Methodology Applied
Scientific EffectStimulated emission: Laser

Data Source

PatentEP1927168B1Optical pulse amplifier with high peak and high average power
Publication Date: 2011.12.14 ECOLE POLYTECHNIQUE
  • EP1927168B1 patent drawingFigure 1
  • EP1927168B1 patent drawingFigure 2
  • EP1927168B1 patent drawingFigure 3

AI summary

The invention relates to an optical pulse amplifier (51) comprising - a first optical fiber amplifier (52a) adapted to receive an input pulse, - a splitter (54a, 54b, 54c) connected to said first optical fiber, said splitter having a plurality of outputs; - a plurality of optical fiber amplifiers (52b, 52c, 52d, 57) , each optical fiber amplifier being connected to one of said plurality of outputs, said plurality of optical fiber amplifiers generating a plurality of output pulse signals. The optical pulse amplifier of the invention has the advantage that it can produce high peak and high average power.