Compressive Sensing Spectrometer for Miniaturization

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Solution Overview

Problem

Existing spectrometry devices face limitations in size, weight, and power consumption, particularly in applications requiring handheld or space-exploration instruments, and struggle with low-light conditions and high-speed detection, which affects accuracy and efficiency in analyzing emitted light spectra.

Innovation Solution

A spectrometer system with an array of interferometers and input waveguides integrated onto a single chip, using compressive sensing techniques to reconstruct emitted light spectra with fewer interferometers than required by the Nyquist criterion, allowing for smaller, lighter devices with improved signal-to-noise ratio and rapid data acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If the number of interferometers is reduced to enable handheld device construction, then device size and weight are improved, but spectral reconstruction accuracy deteriorates due to insufficient sampling per Nyquist criterion

Engineering Contradiction:
Improvespectrometer weightVSAvoidspectral reconstruction accuracy
Core Design Contradiction:
Weight of stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental sampling parameter from uniform Nyquist sampling to non-uniform compressive sensing sampling. By using random or pseudo-random sampling patterns instead of uniform spacing, the system achieves accurate spectral reconstruction with fewer measurements through sparsity exploitation in the frequency domain

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional mechanical scanning interferometer with a static array of fixed-path-length interferometers. This substitution eliminates moving parts, enabling miniaturization while maintaining spectral measurement capability through parallel measurement of multiple path differences

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

2Measurement precision

If more interferometers are used to satisfy Nyquist criterion, then spectral reconstruction accuracy is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvespectral reconstruction accuracyVSAvoidinterferometer array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial sampling by acquiring only a subset of the full Nyquist-required measurements. Through compressive sensing, the system reconstructs the complete spectrum from these partial measurements, achieving adequate accuracy without implementing the full complement of interferometers

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the spectral measurement task into multiple parallel interferometric measurements with different fixed path lengths. Each interferometer contributes a portion of the spectral information, and the complete spectrum is reconstructed by combining these segmented measurements through sparse reconstruction algorithms

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If traditional spectrometer design is used to ensure spectral resolution, then measurement accuracy is maintained, but device size and power consumption increase

Engineering Contradiction:
Improvespectral resolutionVSAvoidspectrometer weight
Core Design Contradiction:
Measurement precisionVSWeight of stationary object

Solution Approach 1:

The patent replaces mechanical scanning systems with a static interferometer array, eliminating motors, scanners, and associated control systems. This substitution dramatically reduces weight and power consumption while maintaining spectral resolution through mathematical reconstruction from multiple fixed-path measurements

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

4Volume of moving object

If fewer interferometers are used, then device size is reduced for handheld applications, but signal-to-noise ratio deteriorates due to reduced sampling

Engineering Contradiction:
Improvespectrometer volumeVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent merges multiple weak interferometric measurements into a single high-quality spectral reconstruction through compressive sensing algorithms. By combining information from fewer interferometers using sparse reconstruction, the system achieves a superior signal-to-noise ratio compared to individual measurements or traditional averaging methods

Inventive Principle:
Principle #5Merging (Combining)

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 the construction of smaller, lighter spectrometers that maintain high spectral resolution and bandwidth while reducing the number of interferometers, enhancing accuracy and speed in spectral analysis, especially in low-light and high-speed applications.

Implementation Method 1

Each interferometer in the array is configured to generate a self-interfering signal output with a known phase shift in response to receiving a portion of the input light signal

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

A plurality of input waveguides may be provided. The plurality of input waveguides may define a waveguide section of the spectrometer

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3318855B1Integrated fourier transform optical spectrometer
Publication Date: 2020.04.01 COM DEV LTD
  • EP3318855B1 patent drawingFigure 1
  • EP3318855B1 patent drawingFigure 2
  • EP3318855B1 patent drawingFigure 3

AI summary

A spectrometer and method for determining an emitted light spectrum. An input light signal is received and directed to an array of interferometers using waveguides. A plurality of self-interfering signals are detected from a first plurality of interferometers in the array of interferometers. The first plurality of interferometers has fewer interferometers than required to satisfy the Nyquist criterion for reconstructing the emitted light spectrum. The emitted light spectrum is reconstructed from the plurality of self-interfering signals using compressive sensing. The plurality of self-interfering signals can provide an interference pattern used to reconstruct the emitted light spectrum. A second plurality of interferometers may output a second plurality of self-interfering signals to reconstruct a low resolution spectrum of the input light signal satisfying the Nyquist criterion. Low resolution signal components can be detected from the low resolution spectrum and used to pre-process the interference pattern.