Edge-Emitting Laser Reflector Modulation for Fringe Artifact Reduction

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Solution Overview

Problem

Narrow spectral bandwidth of lasers in waveguide-based displays causes high-contrast fringe artifacts and sharp field of view boundaries, which detract from the user experience by creating interference fringes and distinct image boundaries.

Innovation Solution

An edge-emitting laser with a tunable wavelength range, achieved through high-frequency index modulation of the reflector section, broadens the perceived bandwidth of light output, reducing fringe interference by increasing the number of interfering wavelengths and blurring out field of view boundaries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a laser with narrow spectral bandwidth is used in waveguide-based displays, then the laser provides coherent light with high intensity and directionality, but it causes high-contrast fringe artifacts and sharp field of view boundaries

Engineering Contradiction:
Improvelaser intensityVSAvoidfringe artifacts
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the reflector section tunable through high-frequency index modulation, allowing the laser wavelength to be dynamically adjusted. This dynamic wavelength tuning broadens the perceived bandwidth of the laser output, which reduces the visibility of fringe artifacts while maintaining the intensity and coherence benefits of laser light.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the wavelength parameter of the laser through high-frequency index modulation of the reflector section. By modulating the refractive index of the reflector section at high frequencies, the laser wavelength is tuned across a range of values, effectively broadening the spectral bandwidth and reducing fringe artifact visibility.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a laser with narrow spectral bandwidth is used in waveguide-based displays, then the laser provides coherent light with well-defined properties, but it creates distinct image boundaries and reduces user experience

Engineering Contradiction:
Improvelaser coherenceVSAvoidfield of view boundaries
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The reflector section is designed to be dynamically tunable through high-frequency index modulation, enabling the laser to operate across a range of wavelengths. This dynamic adjustment broadens the perceived bandwidth, which softens the field of view boundaries and improves user experience while preserving laser coherence.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent modifies the wavelength parameter of the laser by applying high-frequency index modulation to the reflector section. This parameter change broadens the spectral output, which reduces the sharpness of field of view boundaries and enhances overall user experience without compromising the coherent nature of the laser light.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If high-frequency index modulation is applied to the reflector section, then the perceived bandwidth of light output is broadened, but the device complexity increases

Engineering Contradiction:
Improvewavelength tuning rangeVSAvoidmodulation system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the reflector section with the laser cavity structure, integrating the wavelength tuning functionality directly into the laser device. This integration reduces the need for separate external modulation systems, thereby broadening the wavelength tuning range while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reflector section serves dual functions: it provides the necessary optical feedback for laser operation and simultaneously enables wavelength tuning through high-frequency index modulation. This self-service approach allows the same component to perform multiple functions, broadening the adaptability of the laser while avoiding additional complexity from separate tuning mechanisms.

Inventive Principle:
Principle #25Self-service

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 effectively reduces the perception of fringe interference artifacts and improves image quality by washing out contrast in interference fringes and blurring field of view boundaries, enhancing the user experience in waveguide-based displays.

Implementation Method 1

The selected wavelength is tunable via high-frequency index modulation of the reflector section

Methodology Applied
Scientific EffectIndex modulation: Refraction

Implementation Method 2

an active gain section configured to amplify an optical power of light across a wavelength range

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 3

The active gain section and the reflector section collectively form an optical cavity configured to lase coherent light in the selected wavelength

Methodology Applied
Scientific EffectOptical feedback: Laser

Data Source

PatentEP3973601B1Edge-emitting laser with high-frequency modulated reflector section
Publication Date: 2024.12.04 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3973601B1 patent drawingFigure 1
  • EP3973601B1 patent drawingFigure 2
  • EP3973601B1 patent drawingFigure 3

AI summary

An edge-emitting laser includes an active gain section and a reflector section optically coupled to the active gain section. The active gain section is configured to amplify an optical power of light across a wavelength range. The reflector section is configured to selectively reflect light of a selected wavelength within the wavelength range. The selected wavelength is tunable via high-frequency index modulation of the reflector section. The active gain section and the reflector section collectively form an optical cavity configured to lase coherent light in the selected wavelength.