Multi-Mode Waveguide Quasi-Phase Matching for High Power

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Solution Overview

Problem

Conventional high power laser sources for mid-wave infrared (MWIR), visible, and near infrared (NIR) wavelengths face design challenges, including limited maximum operating power due to optical damage and practical difficulties in beam coupling and scattering losses, especially in single mode waveguides.

Innovation Solution

A multi-mode waveguide parametric device with alternating oppositely oriented layers provides quasi-phase matching for efficient non-linear coupling, allowing high power generation while maintaining the fundamental mode propagation, reducing scattering losses and enabling longer interaction lengths for efficient wavelength conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If single mode waveguides are used to maintain beam quality, then beam quality is improved, but maximum operating power is limited due to optical damage

Engineering Contradiction:

Improvebeam qualityVSAvoidmaximum operating power

Core Design Contradiction:

Stability of the object's compositionVSPower

Solution Approach 1:

The patent divides the waveguide into multiple transverse modes, allowing the system to operate in a multi-mode regime while using selective mode coupling to maintain fundamental mode propagation. This segmentation of the mode space enables higher power handling while preserving beam quality through controlled mode interactions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operational parameters by transitioning from single-mode to multi-mode waveguide operation, and by dynamically controlling mode coupling parameters. This allows the system to operate at higher powers while maintaining beam quality through parameter optimization rather than being constrained by single-mode limitations.

Inventive Principle:

Principle #35Parameter changes

2Power

If waveguide size is increased to handle higher power, then power capacity is improved, but scattering losses and mode conversion losses increase

Engineering Contradiction:

Improvepower capacityVSAvoidscattering losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent applies local quality control by creating specific regions within the waveguide structure that favor fundamental mode propagation. Through controlled mode coupling and selective interaction regions, the system maintains low scattering losses in critical areas while allowing multi-mode operation in other regions to increase power capacity.

Inventive Principle:

Principle #3Local quality

3Power

If waveguide size is increased to handle higher power, then power capacity is improved, but beam quality deteriorates due to multiple mode generation

Engineering Contradiction:

Improvepower capacityVSAvoidbeam quality

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The patent introduces dynamic control of mode coupling within the waveguide structure. By creating regions that selectively couple modes and regions that maintain mode purity, the system dynamically manages the mode composition to preserve beam quality while operating at high power levels that would otherwise generate excessive modal noise.

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If conventional non-linear conversion processes are used for wavelength conversion, then wavelength conversion is achieved, but the process is costly and relatively ineffective

Engineering Contradiction:

Improvewavelength conversion capabilityVSAvoidconversion efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the waveguide transmission function with the non-linear wavelength conversion function into a single integrated structure. By incorporating non-linear optical materials directly into the multi-mode waveguide and utilizing controlled mode coupling, the system achieves efficient wavelength conversion without requiring separate conversion components, thereby improving both effectiveness and reducing system complexity.

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

The multi-mode waveguide design achieves high power output with reduced scattering and mode conversion losses, maintaining beam quality and extending interaction lengths for efficient conversion, thus overcoming the limitations of single mode waveguides.

Implementation Method 1

providing quasi-phase matching between a signal beam and a pump beam

Methodology Applied

Scientific EffectQuasi-phase matching:

Implementation Method 2

efficient non-linear coupling, allowing high power generation while maintaining the fundamental mode propagation

Methodology Applied

Scientific EffectNon-linear optical coupling:

Implementation Method 3

reducing scattering losses and enabling longer interaction lengths for efficient wavelength conversion

Methodology Applied

Scientific EffectScattering reduction: Scattering

Data Source

PatentUS8169692B2Waveguide parametric device and method

Publication Date: 2012.05.01 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A waveguide parametric device including a multi-mode waveguide having orientation layers formed in a propagation direction of a signal beam and a pump beam propagating down the waveguide. The orientation layers are oppositely oriented to provide non-linear coupling between the pump beam and the signal beam and have a periodicity that provides quasi-phase matching for a fundamental propagation mode, where the waveguide has a size to accommodate multi-mode wave propagation.