Intrinsic Fiber Optic Sensor Interrogation Bandwidth Calibration

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Solution Overview

Problem

Existing fiber optic sensor systems face limitations in efficiently interrogating multiple sensors due to the need for complex spectral filtering and high reflectivity requirements, especially in applications with large sensing ranges and dense sensor arrays, where broadband sources are inefficient and tunable lasers are preferable but require precise wavelength control to avoid incorrect identification of sensor signals.

Innovation Solution

A method for calibrating detection regions in an optical sensor system with intrinsic fiber optic sensors, where the bandwidth of each detection region is adjusted based on the dynamic signal range of the sensor, and recalibrated at predetermined intervals to maintain accurate signal processing and prevent sensor misidentification, allowing for proportional reduction of bandwidth to ensure minimum threshold spacing between regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If broadband sources are used for interrogating fiber optic sensors, then a large wavelength range is covered, but the system becomes inefficient and requires complicated spectral filtering functionality

Engineering Contradiction:
Improvewavelength coverageVSAvoidspectral filtering functionality
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the wavelength spectrum into multiple detection regions, each assigned to specific sensors. This segmentation allows the system to process different wavelength ranges separately, eliminating the need for complex spectral filtering while maintaining the ability to interrogate multiple sensors with different wavelength ranges.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adjustment of detection region bandwidths based on sensor requirements. The bandwidth of each detection region can be proportionally reduced or expanded to accommodate varying sensor dynamic ranges, allowing flexible adaptation without fixed spectral filtering constraints.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If detection region bandwidth is reduced to increase sensor density, then more sensors can be accommodated, but the minimum detectable signal range may be compromised

Engineering Contradiction:
Improvesensor densityVSAvoidsignal detection accuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system dynamically adjusts detection region bandwidths based on individual sensor requirements. Sensors with larger dynamic ranges are allocated wider bandwidths, while sensors with smaller ranges receive narrower bandwidths. This dynamic allocation allows high sensor density while maintaining adequate signal detection accuracy for each sensor type.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Each detection region is customized with specific bandwidth characteristics matched to the requirements of assigned sensors. This local optimization ensures that each sensor operates with the most appropriate bandwidth for its dynamic range, rather than using a uniform bandwidth for all sensors.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If fixed detection regions are assigned to sensors, then signal processing is simplified, but sensors with large sensing ranges may require wide bandwidth while dense arrays need narrow bandwidth

Engineering Contradiction:
Improvesignal processing simplicityVSAvoidbandwidth accommodation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system employs dynamic bandwidth adjustment where detection region widths are modified based on sensor characteristics and array density requirements. This allows the system to adapt between wide bandwidth modes for individual sensor analysis and narrow bandwidth modes for high-density sensor arrays, maintaining processing simplicity through automated region management.

Inventive Principle:
Principle #15Dynamics

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 enhances the ability to accurately process signals from multiple sensors with varying dynamic ranges, improving the density of sensing points and reducing errors in sensor identification, thereby increasing the effectiveness and cost-effectiveness of fiber optic sensor systems.

Implementation Method 1

An intrinsic fiber optic sensor is a sensor that uses an optical fiber as the sensing element

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Fiber Bragg Gratings are localized and narrow band reflectors whose reflection wavelength, also known as the Bragg wavelength, change due to extrinsic effects such as strain and temperature

Methodology Applied
Scientific EffectBragg diffraction: Bragg Diffraction

Data Source

PatentEP3574289B1System and method for interrogating an intrinsic fiber optic sensor
Publication Date: 2022.08.03 OPTICS11 FAZ LTD
  • EP3574289B1 patent drawingFigure 1
  • EP3574289B1 patent drawingFigure 2
  • EP3574289B1 patent drawingFigure 3

AI summary

The present invention provides a method for measuring an optical sensor system comprising an array of intrinsic fiber optic sensors at an interrogator comprising an optical source and an optical detector. The method comprises the steps of emitting an optical signal to an array of intrinsic fiber optic sensors; detecting optical responses to the emitted signal from the sensors; associating each detected optical response with an individual sensor by determining within which region among a plurality of detection regions assigned to the individual sensors the optical response is detected wherein each detection region corresponds to a wavelength range in the bandwidth of the optical sensor system; and performing signal processing on each optical response to measure the value of the physical parameter detected by its associated sensor. A calibration of the detection region assigned to each sensor is performed at predetermined intervals.