Single-Emitter Beam Stacking for Compact WBC Laser Arrays

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Solution Overview

Problem

Existing wavelength beam combining (WBC) systems using diode bars face issues such as the need for beam rotators, increased system costs, power loss, optical aberrations, and complexities due to emitter smile and thermal crosstalk.

Innovation Solution

The use of stacked single beam emitters, where each emitter is arranged to share a single slow-axis collimation lens and have identical optical path lengths, allows for beam stacking in the fast-axis dimension without the need for beam rotators, reducing costs and improving beam quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If diode bars are used in WBC systems, then multiple beams can be combined to increase output power, but beam rotators are required which increase system cost and complexity

Engineering Contradiction:

Improveoutput powerVSAvoidsystem complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The invention segments the multi-beam emitter into multiple single-emitter modules, each emitting a single beam. This segmentation eliminates the need for beam rotators while maintaining the capability to combine multiple beams for high output power, thereby reducing system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the beam combining dimension from slow-axis to fast-axis by arranging single emitters in a specific geometric configuration. This dimensional change allows direct beam combination without rotators, reducing system complexity while preserving power scaling capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If beam rotators are used to facilitate fast-axis beam combining, then beam quality is improved, but power loss and optical aberrations occur

Engineering Contradiction:

Improvebeam qualityVSAvoidpower loss

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

Instead of using beam rotators to change the combining dimension, the invention inverts the approach by directly arranging single emitters to combine beams in the fast-axis dimension. This eliminates the need for rotators, preventing power loss and optical aberrations while maintaining beam quality.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If multiple SAC lenses are used for each diode bar, then beam collimation is improved, but system cost and space requirements increase

Engineering Contradiction:

Improvebeam collimationVSAvoidsystem cost

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges the collimation function by using a single shared SAC lens for multiple single-emitter modules. This consolidation maintains proper beam collimation while reducing system cost and space requirements compared to using separate SAC lenses for each diode bar.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared SAC lens serves multiple single-emitter modules simultaneously, providing universal collimation functionality. This multi-functionality reduces the total number of optical components needed, lowering system cost and complexity while maintaining collimation quality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Power

If diode bars with multiple emitters are used, then output power is increased, but thermal crosstalk and emitter smile complications arise

Engineering Contradiction:

Improveoutput powerVSAvoidemitter stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The invention segments the multi-emitter diode bar into multiple independent single-emitter modules. This segmentation eliminates thermal crosstalk between emitters and removes emitter smile complications, while the modular architecture allows scaling to high output powers by combining multiple stable emitter modules.

Inventive Principle:

Principle #1Segmentation

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 results in reduced system costs, increased compactness, improved beam quality, lower operating currents, minimized thermal crosstalk, and longer emitter lifetimes, leading to more efficient and reliable WBC laser systems.

Implementation Method 1

shared collimation optics, specifically a single shared slow-axis collimation (SAC) lens... identical optical path lengths between each emitter and the shared collimation lens

Methodology Applied

Scientific EffectCollimation: Lens

Implementation Method 2

Wavelength beam combining (WBC) is a technique for scaling the output power and brightness from laser diodes... combined using a dispersive element

Methodology Applied

Scientific EffectDiffraction: Diffraction Grating

Implementation Method 3

a common partially reflecting output coupler that is filtered by the dispersive element... reflected back through the dispersive element to a focal point... stabilize emission wavelengths

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12327974B2Single emitter stacking for wavelength-beam-combining laser systems

Publication Date: 2025.06.10 WBC PHOTONICS INC

AI summary

In various embodiments, multiple laser emitters are arranged in one or more linear stacks and emit beams to one or more linear stacks of interleaving mirrors. The interleaving mirrors direct the beams to a shared exit point, thereby forming an output beam stack. The optical distances traversed by each beam from its emitter to the shared exit point are all equal to each other.