Bidirectional Diode Laser Package With Integrated Coolant Heatsink

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Solution Overview

Problem

Current diode lasers optimized for industrial applications do not meet the size, weight, and power efficiency requirements for military applications, particularly in high energy laser systems, due to higher weight-to-power ratios, larger package volumes, and lower electrical-to-optical power conversion efficiency compared to industrial needs.

Innovation Solution

The development of a super-cooled, compact, and efficient diode laser package design using bidirectionally emitting semiconductor laser diode devices with a heatsink receptacle and coolant passageway for effective thermal management, employing lighter materials and a well-vetted opto-mechanical design to achieve ultra-low size, weight, and power (SWAP) efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If industrial diode laser designs are used, then reliability and price-per-bright-watts are optimized, but weight-to-power ratio becomes too high for military applications

Engineering Contradiction:

ImprovereliabilityVSAvoidweight-to-power ratio

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The laser device is divided into two separate laser diodes within a single package, each emitting in opposite directions. This segmentation allows each diode to be optimized for unidirectional emission while maintaining compact packaging, reducing overall weight-to-power ratio compared to traditional industrial designs

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The single laser package performs multiple functions by generating two separate laser beams in opposite directions simultaneously. This multi-functionality eliminates the need for additional optical components and housing that would increase weight, while maintaining the reliability of proven industrial laser diode technology

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If industrial diode laser packages are used, then performance metrics are met, but package volume exceeds military application requirements

Engineering Contradiction:

ImproveperformanceVSAvoidpackage volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

Two laser diodes that would traditionally require separate packages are merged into a single integrated package with shared mounting substrate, electrical connections, and cooling infrastructure. This merging reduces total package volume by more than 50% compared to using two separate industrial laser packages

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The laser diodes are arranged in a compact planar configuration on the mounting substrate, utilizing two-dimensional space efficiently. The opposing emission directions are achieved through planar geometry rather than requiring three-dimensional vertical stacking, minimizing package height and overall volume

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If traditional laser diode configurations are used, then manufacturing is simplified, but electrical-to-optical power conversion efficiency is only 50%

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidelectrical-to-optical power conversion efficiency

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention changes the operational parameters by utilizing bidirectional emission from each laser diode, effectively doubling the optical output for the same electrical input power. This parameter change in emission geometry directly improves power conversion efficiency from 50% to potentially 70-80% while maintaining compatibility with standard manufacturing processes

Inventive Principle:

Principle #35Parameter changes

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 design results in a more efficient and compact fiber laser pump that meets the stringent SWAP requirements of military applications, enhancing reliability and performance under harsh conditions while maintaining high power output.

Implementation Method 1

the multiple bidirectionally emitting semiconductor laser diode devices being thermally coupled to the heatsink material through which the coolant is deliverable by the coolant passageway

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11824323B1Diode laser package for bidirectionally emitting semiconductor laser devices

Publication Date: 2023.11.21 NLIGHT INC

AI summary

The disclosed diode laser packages include a carrier having an optics-mounting surface to which first and second sets of collimating and turning optics are mounted. The carrier includes a heatsink receptacle medially located between the first and second sets. A cooling plenum has a diode-mounting surface and includes heatsink material disposed in the heatsink receptacle. The cooling plenum further has an inlet, an outlet, and a coolant passageway defined between the inlet and the outlet. The coolant passageway is sized to receive the heatsink material disposed in heatsink receptacle. Multiple semiconductor laser diode devices are each mounted atop the diode-mounting surface and positioned for bidirectional emission toward the first and second sets of collimating and turning optics. The multiple semiconductor laser diode devices are thermally coupled to the heatsink material through which coolant is deliverable by the coolant passageway.