Channel Dispersed Fourier Transform Spectrometer for Compact High-Resolution Optical Analysis

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Solution Overview

Problem

Conventional optical Fourier Transform (FT) spectrometers are limited by their large footprint and mechanical stability requirements, making them unsuitable for compact, portable applications while maintaining high resolution and signal fidelity, and their sampling geometry restricts maximum achievable resolution, hindering widespread adoption in miniaturized forms.

Innovation Solution

The proposed solution involves channel dispersed Fourier Transform (CDFT) spectroscopy, which splits the input signal spectrum into spectral bands, analyzes each band using a Fourier transform spectrometer, and combines the outputs to generate a final spectrum, relaxing sampling rate and dynamic range requirements, and using integrated silicon-on-insulator (SOI) FTS with microheaters for compact, high-resolution spectrometers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical Fourier Transform spectrometers are used to maintain high resolution and signal fidelity, then measurement accuracy is improved, but device footprint and mechanical stability requirements increase

Engineering Contradiction:

Improvespectral resolutionVSAvoiddevice footprint

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The broadband signal spectrum is divided into multiple spectral bands using filters, with each band processed by a separate Fourier transform spectrometer. This segmentation allows each individual spectrometer to have a smaller footprint while collectively achieving high-resolution broadband spectral measurement through the combination of multiple channel spectrums.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If conventional Fourier Transform spectrometers are used to achieve high resolution, then spectral fidelity is improved, but sampling rate and dynamic range requirements increase

Engineering Contradiction:

Improvespectral fidelityVSAvoidmeasurement speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

By dividing the broadband signal into multiple spectral bands, each channel can be measured independently with relaxed sampling rate requirements. The overall measurement speed is improved because each individual Fourier transform spectrometer operates at lower sampling rates while the parallel processing of multiple channels compensates for the distributed measurement approach.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each Fourier transform spectrometer processes only a portion of the total spectrum rather than the entire broadband signal. This partial action approach reduces the sampling rate and dynamic range requirements for each individual channel while maintaining overall spectral fidelity through the combination of all channel spectrums.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If conventional Fourier Transform spectrometers are used to maintain signal fidelity, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvesignal fidelityVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system is divided into multiple independent Fourier transform spectrometer channels, each processing a specific spectral band. This modular segmentation maintains signal fidelity within each channel while reducing the overall complexity of any single spectrometer unit, making the system more suitable for miniaturization and integration.

Inventive Principle:

Principle #1Segmentation

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 approach enables faster measurement speeds and improved spectral resolution in compact forms without sacrificing signal fidelity, suitable for miniaturized applications, and reduces the dynamic range requirements, enhancing the usability of FT spectrometers in portable devices.

Implementation Method 1

computing a one-dimensional Fourier transform of a function of the spectral channel interferogram to generate a channel spectrum

Methodology Applied

Scientific EffectFourier transform:

Implementation Method 2

each of the plurality of filters is configured to filter a distinct spectral portion of an input broadband signal

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

spectrally partitioning the broadband signal to generate a plurality of spectral channel interferograms

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS11280676B2Optical spectroscopy using the fourier transform

Publication Date: 2022.03.22 RGT UNIV OF CALIFORNIA

AI summary

Devices, systems and methods for optical spectroscopy using a Fourier transform that improve measurement speed, and relax the sampling rate and dynamic range requirements compared to conventional techniques, are described. One exemplary method for optical Fourier transform spectroscopy includes receiving a broadband signal, spectrally partitioning the broadband signal to generate a plurality of spectral channel interferograms, computing a one-dimensional Fourier transform of a function of each of the plurality of spectral channel interferograms to generate each of a plurality of channel spectrums, and reconstructing a spectrum of the broadband signal based on the plurality of channel spectrums. Embodiments of the disclosed technology include a free-space channel dispersed Fourier transform spectrometer and an integrated silicon-on-insulator Fourier transform spectrometer.