Spatial Interferometer Coherent Light Detection in High-Intensity Sunlight

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Solution Overview

Problem

Existing coherence detection methods, such as temporal scanning, are ineffective for detecting coherent light in the presence of high-intensity light, particularly in space or high orbit where sunlight is near a sensor boresight and wavelengths have not been filtered by the atmosphere, and are also inadequate for short pulsed lasers.

Innovation Solution

A spatial interferometer with multiple openings, a photo detector array, and a processor that integrates pixel outputs to determine coherent light directionality and wavelength by analyzing interference patterns without moving parts, using Fourier transforms to identify coherent light in the presence of incoherent high-intensity light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temporal scanning methods are used to detect coherent light, then the system can detect coherent light under normal conditions, but the system becomes ineffective in the presence of high-intensity light such as sunlight in space or high orbit

Engineering Contradiction:
Improvecoherent light detection reliabilityVSAvoidinterference from high-intensity sunlight
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the detection function into multiple spatial channels using an array of photodetectors, each detecting light from a different spatial location. The coherent light creates a specific spatial interference pattern across this array that can be distinguished from the uniform background of sunlight, enabling detection in high-intensity environments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from temporal scanning (time domain) to spatial interferometry (space domain). By using multiple photodetectors arranged in space and analyzing the spatial interference pattern, the system can detect coherent light simultaneously without temporal scanning, making it effective for short pulsed lasers and resistant to high-intensity background light.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Duration of action of moving object

If temporal scanning methods are used to detect coherent light, then the system can operate with continuous light sources, but the system becomes ineffective for short pulsed lasers that are discontinuous over time

Engineering Contradiction:
Improvedetection time windowVSAvoiddetection effectiveness for pulsed lasers
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent performs the interference measurement simultaneously across all spatial channels at the moment the pulsed laser arrives, without requiring temporal scanning. This preliminary capture of the spatial interference pattern ensures that even extremely short pulsed laser signals are detected before they disappear, making the system effective for discontinuous light sources.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If spatial interferometer with multiple photodetectors is used, then the system can detect coherent light in high-intensity environments, but the device complexity increases compared to temporal scanning systems

Engineering Contradiction:
Improveresistance to high-intensity background lightVSAvoidsystem structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical temporal scanning mechanism with a static spatial interferometer and electronic signal processing. The array of photodetectors and processor analyze spatial interference patterns electronically, eliminating moving parts while achieving robust detection in high-intensity environments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables effective detection of coherent light in high-intensity environments, including space-based applications, by accurately determining wavelength and directionality through snapshot detection and Fourier transforms, facilitating communication links and alert systems.

Implementation Method 1

The coherent light interfering with itself to create a light fringe

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

an array of pixels, each configured to detect an intensity of coherent light

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3825666B1Coherent light detection system and method
Publication Date: 2026.03.04 THE BOEING CO
  • EP3825666B1 patent drawingFigure 1~2
  • EP3825666B1 patent drawingFigure 3
  • EP3825666B1 patent drawingFigure 4~5

AI summary

A method for detecting coherent light that includes configuring a spatial interferometer, receiving the coherent light through the spatial interferometer, and disposing a photo detector adjacent to the spatial interferometer. The spatial interferometer is configured such that a coherent light passing through the spatial interferometer interferes with itself. The interference of the coherent light with itself creates a light fringe. The light fringe projects onto the photo detector. The photo detector has an array of pixels operable to detect an intensity of coherent light. The array of pixels provides a plurality of outputs corresponding to coherent light received by discrete pixels of the array of pixels. The method includes determining an interference pattern of the light fringe based on the plurality of outputs of the array of pixels, and determining one or more wavelengths of the coherent light from the interference pattern.