Fiber-Based Optical Parametric Oscillator for High-Energy Pulse Scaling

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Solution Overview

Problem

Ultrafast fiber optical parametric oscillators (FOPOs) face limitations in achieving high output pulse energy and peak power due to nonlinear distortion, which is exacerbated by pulse breaking, and existing systems often require free-space components for alignment, complicating the setup and reducing efficiency.

Innovation Solution

A synchronously pumped FOPO operating in the normal dispersion regime is designed with a highly chirped pulse structure, utilizing an Er-doped fiber amplifier and dispersion-shifted fiber to generate chirped pulses that can be compressed, achieving significant pulse energy scaling without pulse breaking, and featuring an all-fiber laser cavity for alignment-free operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If ultrafast FOPO uses traditional configuration with free-space optics, then output pulse energy and peak power can be achieved, but alignment complexity and system complexity increase significantly

Engineering Contradiction:
Improveoutput pulse energy and peak powerVSAvoidalignment complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent replaces free-space optical components with an all-fiber laser cavity configuration. The fiber optic parametric oscillator uses fiber-based components throughout, eliminating the need for free-space alignment and mechanical adjustment mechanisms, thus reducing device complexity while maintaining power output capabilities

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

Solution Approach 2:

The patent integrates the pump laser, parametric gain medium, and resonating cavity into a unified all-fiber structure. By merging these previously separate components into a single integrated fiber-based system, the patent eliminates alignment interfaces and reduces overall system complexity

Inventive Principle:
Principle #5Merging (Combining)

2Power

If FOPO operates in anomalous dispersion regime, then soliton formation occurs, but pulse breaking and nonlinear distortion limit output energy scaling

Engineering Contradiction:
Improveoutput pulse energyVSAvoidpulse stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent changes the dispersion regime parameter from anomalous to normal dispersion. This parameter change fundamentally alters the pulse dynamics, preventing soliton formation and pulse breaking while enabling reliable output energy scaling up to 1.45 nJ without the limitations imposed by nonlinear distortion in the anomalous regime

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful effect of normal dispersion (which typically limits pulse compression) into a benefit by using it to prevent pulse breaking. In the normal dispersion regime, the pulse experiences controlled stretching that prevents the catastrophic nonlinear effects seen in anomalous dispersion, thereby enabling stable high-energy operation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If FOPO uses short fiber length (2 cm) to avoid nonlinear effects, then pulse quality is maintained, but cavity length and system complexity increase due to free-space optics

Engineering Contradiction:
Improvepulse qualityVSAvoidcavity configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the fiber length parameter from 2 cm to 5 m by operating in the normal dispersion regime. This parameter change enables the use of long fiber lengths without suffering from the nonlinear effects that would occur in the anomalous regime, allowing the entire cavity to be fiber-based without compromising pulse quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the hybrid free-space/fiber cavity configuration with a completely fiber-based cavity. This substitution eliminates the need for free-space optical components and their associated alignment mechanisms, reducing device complexity while maintaining pulse quality through the use of appropriate fiber length and dispersion management

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

4Adaptability or versatility

If FOPO requires free-space components for alignment, then wavelength tuning is possible, but operational efficiency and ease of operation decrease

Engineering Contradiction:
Improvewavelength tuning rangeVSAvoidalignment-free operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces free-space optical components with fiber-based components throughout the cavity. This substitution maintains wavelength tuning capability through fiber-based mechanisms while eliminating the need for mechanical alignment, thereby improving ease of operation without sacrificing adaptability

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

Solution Approach 2:

The all-fiber cavity design provides universal functionality by integrating wavelength tuning, pulse generation, and signal transmission within a single fiber-based platform. This multi-functional integration eliminates the need for separate alignment mechanisms while maintaining broad wavelength tuning capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves an average output power of ~60 mW at 1600 nm with 1.45 nJ pulse energy and 55% slope power conversion efficiency, with pulses compressible to 180 fs, and allows for wide wavelength tuning without the need for free-space alignment, enhancing the operational efficiency and flexibility of the FOPO.

Implementation Method 1

utilizing an Er-doped fiber amplifier

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 2

dispersion-shifted fiber to generate chirped pulses that can be compressed

Methodology Applied
Scientific EffectChromatic dispersion: Dispersion (of waves)

Implementation Method 3

The operation of FOPOs is in essence based on degenerated four-wave-mixing (FWM) wherein two pump photons interact with the fiber to generate a signal photon and an idler photon

Methodology Applied
Scientific EffectFour-wave mixing:

Implementation Method 4

Light sources based on optical parametric interaction are interesting since they provide access to laser wavelengths that existing gain materials based on electronic transitions cannot provide

Methodology Applied
Scientific EffectOptical parametric interaction:

Data Source

PatentEP3020104B1Dissipative soliton mode fiber based optical parametric oscillator
Publication Date: 2020.02.26 CANON KK
  • EP3020104B1 patent drawingFigure 1~2
  • EP3020104B1 patent drawingFigure 3~4
  • EP3020104B1 patent drawingFigure 5~6

AI summary

A fiber optic parametric amplifier that includes a resonating cavity. The resonating cavity includes linear fiber optic gain medium, with negative chromatic dispersion; and a nonlinear fiber optic gain medium with positive chromatic dispersion.