Two-Section Edge-Emitting Laser for Waveguide Fringe Reduction
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Solution Overview
Problem
Waveguide-based laser scanning displays suffer from image quality degradation due to interference fringes caused by coherent light paths with matching optical path lengths, leading to artifacts that reduce perceived image quality.
Innovation Solution
An edge-emitting laser with an optical cavity having both an active gain section and a passive section is used, where the passive section increases the cavity length without amplifying light power, ensuring that coherence peaks do not overlap with waveguide-supported optical path lengths, thereby reducing fringe interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical cavity length is increased to reduce fringe interference, then image quality is improved, but the power consumption increases
Solution Approach 1:
The optical cavity is divided into two distinct sections: an active gain section that amplifies light and a passive section that extends the cavity length without additional amplification. This segmentation allows the laser to achieve the longer cavity length needed to avoid fringe interference while limiting power consumption to only the necessary active region, rather than requiring the entire cavity length to be active.
2Manufacturing precision
If the optical cavity length is increased to avoid coherence peak overlap, then fringe interference is reduced, but device complexity increases
Solution Approach 1:
The optical cavity is segmented into active and passive sections, where the passive section serves the specific function of extending cavity length to adjust coherence properties without requiring active amplification. This functional segmentation simplifies the overall device design by assigning specific roles to each section, avoiding the need for complex active components throughout the entire cavity length.
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 effectively mitigates fringe interference while maintaining low power consumption, resulting in improved image quality and reduced power usage compared to lasers with a single active gain section.
Implementation Method 1
an active gain section configured to amplify an optical power of light reflecting within the optical cavity
Implementation Method 2
a passive section configured to increase a functional length of the optical cavity without further amplifying the optical power of light reflecting within the optical cavity, wherein a total length of the optical cavity reduces fringe interference
Data Source
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AI summary
A system includes a waveguide and an edge-emitting laser. The edge-emitting laser is configured to lase coherent light into the waveguide. The edge-emitting laser includes an optical cavity having an active gain section and a passive section. The active gain section is configured to amplify an optical power of light reflecting within the optical cavity. The passive section increases a functional length of the optical cavity such that a total length of the optical cavity reduces fringe interference of the coherent light propagating through the waveguide.