Microchannel Cooler for Laser Diode Emitter Thermal Management
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Solution Overview
Problem
Semiconductor laser diodes face thermal dissipation challenges due to high heat dissipation per unit area, leading to elevated junction temperatures and reduced efficiency and service life, especially when densely packed for use in solid state laser systems, which affects wavelength stability and pumping uniformity.
Innovation Solution
A micro-channel cooled laser apparatus with a pump layer and intermediate layer featuring radially arranged micro-channels for coolant flow, allowing efficient heat dissipation from single emitter laser diodes arranged transversely around a laser medium, combining the compactness of laser diode bars with the effectiveness of micro-channel cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple laser diodes are densely packed into arrays to generate required input power for solid state laser systems, then the power output is improved, but the heat dissipation capability deteriorates due to decreased space for heat extraction
Solution Approach 1:
The patent embeds micro-channels within the substrate layers themselves, nesting the cooling function inside the structural support layers. The micro-channels are formed within the substrate material, allowing coolant to flow through channels that are integrated into the mechanical support structure, maximizing heat extraction from densely packed diodes while maintaining structural integrity
Solution Approach 2:
The patent employs hydraulic cooling by circulating coolant through micro-channels formed in the substrate. The fluid flow through these channels provides direct thermal contact with the laser diode junctions, efficiently removing heat from the densely packed array and maintaining operational temperatures
2Power
If the junction temperature is increased to improve power output, then the efficiency and service life of the laser diode deteriorate
Solution Approach 1:
The patent introduces coolant as an intermediary substance that mediates heat transfer between the laser diode junctions and the external environment. The coolant flows through micro-channels in direct thermal contact with the diodes, acting as an intermediate heat transfer medium that maintains junction temperatures within reliable operating ranges while allowing high power output
Solution Approach 2:
The patent changes the thermal parameter of the system by implementing active coolant circulation through micro-channels. This transforms the thermal management approach from passive conduction to active convection, enabling the system to maintain low junction temperatures even at high power outputs, thereby preserving both efficiency and service life
3Device complexity
If the junction temperature varies to simplify cooling, then the wavelength stability of the laser diode deteriorates
Solution Approach 1:
The substrate layers serve multiple functions simultaneously: they provide mechanical support for the laser diodes, electrical isolation between components, and thermal management through integrated micro-channel cooling. This multi-functionality allows the same structural elements to perform cooling duties without adding separate complexity to the 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 configuration provides enhanced heat management, maintaining stable junction temperatures, improving efficiency and service life, and enabling more uniform pumping with reduced stress birefringence, while allowing for compact and robust arrangements of laser diodes.
Implementation Method 1
A coolant source is fluidly coupled to the micro-channels to allow coolant to be directed through the microchannels and the radial channel to impinge on the bottom surface of the pump layer and flow through the radial channel
Data Source
AI summary
A laser system that allows transverse arrangement of laser emitters around a laser medium. The system includes a laser medium with a coolant source and electrical controls. A pump layer has a mounting surface, an opposite bottom surface and a center aperture through which the laser medium is inserted. Laser diode emitters are disposed on the mounting surface circumferentially around the laser medium. An intermediate layer has at least one radial channel in fluid communication with the coolant conduit. The intermediate layer is in contact with the bottom surface. A middle layer has micro-channels formed therethrough and a center aperture. The micro-channels are radially arranged around the center aperture and the middle layer is in contact with the intermediate layer. The coolant source is fluidly coupled to the micro-channels to allow coolant to be directed through the microchannels and the radial channel to impinge on the bottom surface.