Polarization-Multiplexed Laser Element for Higher Output and Lower Heat
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Solution Overview
Problem
Existing laser elements with multi-junction structures face thermal limitations that restrict light output and reduce Mean Time to Failure (MTTF) due to increased junction temperature when power is increased, and existing multiplexing techniques do not effectively enhance peak power without generating heat or reducing operational life.
Innovation Solution
A laser element design incorporating a laminated semiconductor layer, polarization splitting element, and separate reflection layers for orthogonal polarized beams, allowing individual resonance and multiplexing of TE and TM polarized beams, which enhances light output without increasing current and improves thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If power of the excitation light source is increased to increase the light output, then light output is improved, but junction temperature rises and Mean Time to Failure lowers
Solution Approach 1:
The invention divides the excitation light source into multiple independent light emitting units (first, second, third light emitting units) that can operate separately. This segmentation allows the total light output to be increased by activating more units rather than increasing the power of individual units, thereby avoiding excessive junction temperature rise and maintaining reliability.
Solution Approach 2:
The invention combines multiple light emitting units with different polarization characteristics (TE-polarized and TM-polarized) to achieve higher total light output. By merging these units in a multi-junction semiconductor layer structure and using polarization multiplexing, the system achieves increased illumination intensity without proportionally increasing power consumption per unit, thus improving light output while maintaining thermal management and reliability.
2Illumination intensity
If a multi-junction structure with laminated semiconductor layers is used, then light output can be increased, but thermal resistance increases and upper limit of light output is reached
Solution Approach 1:
The invention utilizes polarization dimension to multiply the light output. By creating separate optical paths for TE-polarized and TM-polarized light through polarization splitting elements and corresponding reflection layers, the system effectively doubles the usable light output from the same physical structure without increasing thermal load in a single path, thus overcoming the thermal resistance limitation of multi-junction structures.
Solution Approach 2:
The invention segments the light emission into multiple independent channels based on polarization states. Each light emitting unit is associated with specific polarization characteristics, and the system uses separate reflection layers and polarization splitting elements to guide these segmented light paths independently, allowing increased total output without concentrating thermal energy in a single path.
3Illumination intensity
If spatial multiplexing or polarization multiplexing is used to increase average output, then average output is improved, but peak power cannot be improved due to waveform jitters
Solution Approach 1:
The invention preliminarily separates the light paths by polarization state using polarization splitting elements before the light reaches the output. By pre-organizing TE-polarized and TM-polarized light into distinct paths with dedicated reflection layers, the system maintains coherent waveforms in each path while achieving high peak power through constructive interference at the output, avoiding the waveform jitter problems associated with post-hoc multiplexing methods.
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 design doubles light output and extends operational life by maintaining high excitation light output with reduced current, improving mass productivity and MTTF through efficient thermal management and polarization multiplexing.
Implementation Method 1
a polarization splitting element that individually resonates and multiplexes each of orthogonal polarized beams included in light emitted from the laminated semiconductor layer
Implementation Method 2
a first reflection layer used for light of a first wavelength... a second reflection layer that is disposed closer to a light emission surface side than the laminated semiconductor layer, and is used for the light of the first wavelength
Implementation Method 3
the polarization splitting element may multiplex the TE polarized beam with the TM polarized beam inside the polarization splitting element
Data Source
AI summary
[Problem] An excitation light output is improved without generating heat and lowering an operational life. [Solution] A laser element includes: a laminated semiconductor layer that includes a first reflection layer used for light of a first wavelength and an active layer that performs surface light emission at the first wavelength; a second reflection layer that is disposed closer to a light emission surface side than the laminated semiconductor layer, and is used for the light of the first wavelength; and a polarization splitting element that individually resonates and multiplexes each of orthogonal polarized beams included in light emitted from the laminated semiconductor layer between the first reflection layer and the second reflection layer.