Multi-Stripe Edge-Emitting Laser for Wide Dynamic Range Control
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) suffer from limited dynamic range (DR), making it difficult to accurately represent low luminance content due to challenges in laser power control at lower power levels, exacerbated by thermal and electrical cross-talk and temperature dependency of laser threshold currents.
Innovation Solution
A multi-stripe edge-emitting laser with a lower power optical cavity and a higher power optical cavity, each with distinct active gain sections of varying lengths, is controlled to selectively lase light for different luminance levels, extending the dynamic range and reducing sensitivity to threshold current uncertainty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate laser devices are used to provide different wavelengths, then wavelength diversity is improved, but device complexity and cost increase
Solution Approach 1:
The laser device is segmented into multiple independent stripe regions within a single laser bar, where each stripe can be independently controlled to emit at different wavelengths. This allows wavelength diversity without requiring multiple separate laser devices, thereby reducing overall system complexity while maintaining adaptability.
Solution Approach 2:
A single laser device is designed to perform multiple functions by incorporating multiple stripe regions that can emit different wavelengths simultaneously or independently. This multi-functional design eliminates the need for multiple specialized laser devices, reducing device complexity and integration requirements while providing wavelength diversity for various applications.
2Adaptability or versatility
If multiple separate laser devices are used, then wavelength options are improved, but integration complexity increases
Solution Approach 1:
Multiple laser stripes that emit different wavelengths are merged into a single integrated laser device structure. This consolidation provides multiple wavelength options while simplifying integration compared to combining multiple separate laser devices, as all stripes are fabricated and packaged together as one unit with shared mounting and optical interfaces.
3Ease of manufacture
If conventional laser designs are used, then manufacturing is simpler, but heat dissipation and reliability are worsened
Solution Approach 1:
The laser device is divided into multiple independent stripe regions, each with its own heat dissipation path through the substrate. This segmentation allows heat from each stripe to be conducted separately to the heat sink, improving overall heat dissipation efficiency and reliability while maintaining a relatively simple monolithic manufacturing process.
Solution Approach 2:
Each stripe region is designed with localized heat dissipation characteristics, allowing thermal management to be optimized for each individual stripe. This local optimization of heat dissipation improves reliability without requiring complex overall device redesign, as each stripe can be independently thermal-managed within the unified device structure.
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 extended dynamic range and improved laser power control, enabling accurate representation of a wider range of luminance levels with reduced sensitivity to threshold current fluctuations.
Implementation Method 1
edge-emitting laser device that provides multiple wavelengths of light
Implementation Method 2
distributed feedback (DFB) laser
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An edge-emitting laser 302 including a substrate 303, a lower power optical cavity 300 located on the substrate and a higher power optical cavity 304 located on the substrate adjacent the lower power optical cavity. The lower power optical cavity includes a first active gain section 301 having a first length LL. The higher power optical cavity includes a second active gain section 305 having a second length LH greater than the first length. The optical cavities can excited separately or collectively depending on the desired output power. The lower/higher power optical cavities 400, 414 may further include passive sections 406, 418 to form an extended cavity laser with increased functional length of the optical cavity to reduce fringe interference.