Integrated Optical Waveguide Ring Resonator for Remote Gas Detection
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Solution Overview
Problem
Conventional remote gas sensing technologies are bulky, expensive, and slow, requiring long exposure times and complex systems for molecular detection, which limits their effectiveness in applications where compactness and speed are crucial.
Innovation Solution
An integrated optical waveguide ring resonator on a silicon chip is used, which supports input and output waveguides and has a transmission spectrum matching the absorption or emission spectrum of the target gas, allowing for compact, cost-effective, and spectrally tuned detection of remote gases using a broadband light source and active index modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional dispersive spectrometers are used for remote gas sensing, then molecular composition can be determined, but the system size and complexity increase significantly
Solution Approach 1:
The patent extracts only the specific spectral information needed for target gas detection from the full spectrum, using a correlation filter that matches only the absorption features of the target molecule. This eliminates the need for complex dispersive spectrometers that capture and process entire spectra, reducing system complexity while maintaining detection precision.
Solution Approach 2:
The correlation filter is designed to be universally applicable for detecting specific molecular signatures in various remote sensing applications (atmospheric monitoring, astronomical spectroscopy, emissions detection) without requiring different instrument configurations, thereby reducing overall system complexity across multiple use cases.
2Measurement precision
If conventional dispersive spectrometers are used for remote gas sensing, then complete spectral information is obtained, but the device size becomes large
Solution Approach 1:
The patent extracts only the specific spectral features of the target gas using a correlation filter, discarding unnecessary spectral information. This allows the use of compact integrated photonic devices instead of large dispersive spectrometers, significantly reducing device size while retaining essential spectral information for gas detection.
Solution Approach 2:
The patent changes the spectral bandwidth parameter by using a correlation filter with a narrow passband matched to the target gas absorption features. This selective parameter change enables compact device design by focusing only on the relevant spectral region rather than processing the entire spectrum.
3Measurement precision
If long telescopic exposure times are used for weak signals, then signal detection sensitivity is improved, but 1/f noise limitations prevent further signal to noise ratio improvement
Solution Approach 1:
The patent replaces the mechanical approach of increasing exposure time with an optical correlation method. The correlation filter performs real-time spectral matching, substituting temporal integration with spatial-spectral processing. This eliminates 1/f noise limitations while maintaining high signal-to-noise ratios for weak signals.
Solution Approach 2:
The correlation filter provides real-time feedback by continuously comparing the incoming spectral signal with the reference absorption pattern. This active correlation process enhances signal-to-noise ratio dynamically without requiring prolonged exposure times, overcoming the fundamental noise limitations of passive integration.
4Volume of moving object
If integrated photonic systems are used for compact sensing, then device size is reduced, but remote detection capability is lost
Solution Approach 1:
The patent introduces a correlation filter as an intermediary optical element that enables remote detection through integrated photonic systems. The filter correlates the broadband light signal with the target gas absorption spectrum, allowing compact integrated devices to perform remote sensing functions previously requiring large conventional systems.
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 on-chip detection and identification of remote molecular species without acquiring a full spectrum, reducing system size and complexity while maintaining high detectivity, and can be used for gases like hydrogen cyanide and other species with quasi-periodic absorption features.
Implementation Method 1
Absorption spectroscopy is an important tool for the determination of molecular composition where direct interaction with a target gas is not practical or feasible
Implementation Method 2
Many molecular species can be detected and identified by their unique absorption spectrum that results from their vibrational and rotational mode distributions
Implementation Method 3
integrated optical waveguide ring resonator on a silicon chip which supports one or more input and output waveguide. The input and output waveguides support the transmission of light on the chip such that light can be coupled into and out of the component
Data Source
AI summary
An integrated optical sensor enables the detection and identification of one or more remote gases using a transmission filter that matches specific absorption features of a remote gas and is detected using a single photodetection element. The sensor comprises an integrated optical component that is characterized by its transmission spectrum which corresponds to absorption or emission features of a target gas over a defined spectral bandpass, and the ability to have a reversibly tunable transmission spectrum. The change in the optical power output from the sensor as the transmission spectrum is tuned is proportional to the optical depth of the target gas absorption lines when viewed with a background light source. The optical power output from the integrated optical component is therefore related to the absorption spectrum of the input light Physical properties of the sensor are tailored to produce a quasi-periodic transmission spectrum that results in a stronger signal contrast for a specific gas. The sensor is preferably a waveguide ring resonator with a free spectral range that matches the absorption spectrum of a gas over a finite spectral bandpass.