Multi-Emitter Laser Bar on Semipolar GaN for Thermal Stability
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Solution Overview
Problem
Conventional high power laser diodes operating in blue and green regimes face inefficiencies, size issues, and high costs due to reliance on polar c-plane GaN substrates, which limit their application in optical storage and display systems, and are prone to thermal degradation and modulation challenges.
Innovation Solution
The development of bar laser devices configured with multiple emitters on non-polar or semipolar gallium nitride substrates, eliminating aluminum-bearing cladding materials and using c+ and c− oriented facets, allowing for high temperature and power operation without degradation, and enabling broad spectral output for efficient and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If polar c-plane GaN substrates are used for high power laser diodes, then laser output power can be achieved, but thermal degradation and reliability issues occur
Solution Approach 1:
The patent changes the crystallographic orientation parameter from polar c-plane to non-polar or semipolar planes, which fundamentally alters the thermal and electrical properties of the GaN substrate, enabling high power operation without thermal degradation
Solution Approach 2:
The patent employs composite material structures including InGaN quantum wells within AlGaN barrier layers on GaN substrates, creating a multi-layer heterostructure that optimizes both optical performance and thermal management
2Device complexity
If aluminum-bearing cladding materials are used, then device structure is simplified, but thermal degradation occurs at high temperatures
Solution Approach 1:
The patent extracts and removes aluminum-bearing cladding materials from the device structure, eliminating the source of thermal degradation while maintaining device functionality through alternative material compositions
Solution Approach 2:
The patent applies different material compositions to different regions of the device, using aluminum-free materials specifically in high-temperature zones while maintaining aluminum-containing layers only where optically necessary
3Productivity
If multiple emitters are integrated on a single substrate, then productivity and power output increase, but manufacturing complexity increases
Solution Approach 1:
The patent segments the substrate into multiple independent emitter regions, each functioning as a separate laser diode, allowing parallel production and individual optimization while maintaining a unified substrate structure for efficient manufacturing
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 provides high power, reliable, and cost-effective laser devices with extended mean time to failure, capable of emitting broad electromagnetic spectra, suitable for various applications including projection systems, with improved thermal management and reduced form factor.
Implementation Method 1
Each of the plurality of emitters is configured to emit a laser beam in the blue or green wavelength range
Implementation Method 2
an optical device to combine the plurality of laser beams into a single laser beam
Data Source
AI summary
Method and devices for emitting electromagnetic radiation at high power using nonpolar or semipolar gallium containing substrates such as GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, are provided. The laser devices include multiple laser emitters integrated onto a substrate (in a module), which emit green or blue laser radiation.