FBG Sensor Signal Processing with Sweeping Laser and Comparator
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Solution Overview
Problem
Traditional sensors, especially electronic-based ones, are not suitable for harsh environments due to degradation or failure, and Fiber Bragg Grating (FBG) sensors face limitations in measurement speed and complexity in converting reflected wavelengths to parameter measurements.
Innovation Solution
An apparatus using a sweeping wavelength laser (SWL) with a Fiber Bragg Grating (FBG) structure, a photo detector, and a comparator to generate electrical signals and pulses based on threshold comparisons, allowing for faster and more accurate determination of parameter measurements, enabling higher quality and faster data acquisition with multiple FBG structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electronic-based sensors are used, then measurement capability is provided, but reliability deteriorates in harsh environments due to degradation or failure
Solution Approach 1:
The patent replaces electronic-based sensors with optical-based Fiber Bragg Grating sensors. The FBG sensor uses optical principles instead of electronic principles, where an optical fiber contains a grating structure that reflects specific wavelengths of light. This substitution eliminates electronic components that are susceptible to harsh environments (water, corrosion, radiation), providing reliable operation in conditions where traditional electronic sensors would fail or degrade.
2Measurement precision
If complex peak-searching algorithms and analog-to-digital conversion electronics are used to determine time of receiving reflected signal, then measurement capability is provided, but measurement speed deteriorates
Solution Approach 1:
The patent extracts and eliminates the complex analog-to-digital conversion electronics and peak-searching algorithms from the measurement system. Instead of converting the reflected optical signal to electrical signals and performing complex digital processing, the system directly detects the reflected optical signal's wavelength using optical components. This extraction of unnecessary conversion stages simplifies the measurement process and enables faster measurements.
Solution Approach 2:
The patent uses optical copying/detection methods where the reflected optical signal is directly analyzed in the optical domain. Rather than converting to electrical signals for processing, the system uses optical filters or spectrometers to directly determine the reflected wavelength, maintaining measurement precision while eliminating the speed limitations imposed by analog-to-digital conversion and complex algorithms.
3Measurement precision
If complex peak-searching algorithms and analog-to-digital conversion electronics are used, then signal processing capability is provided, but the number of FBG structures that may be employed deteriorates
Solution Approach 1:
The patent removes the complex analog-to-digital conversion electronics and peak-searching algorithms from the system architecture. By eliminating these complex processing stages, the system can handle multiple FBG structures on a single optical fiber without being bottlenecked by processing complexity. The simplified optical detection approach allows parallel or sequential measurement of multiple FBG reflections without requiring complex signal processing for each channel.
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 solution enables faster and more precise parameter measurements in harsh environments, allowing for the use of multiple FBG structures and improved performance in sensing systems.
Implementation Method 1
Each FBG structure is configured to reflect light at a particular wavelength (e.g., a narrowband wavelength range) and pass through light at other wavelengths. The wavelength of the optical signal that the FBG structure reflects depends on the stressed induced from applied strain, either caused by temperature and/or externally applied forces.
Implementation Method 2
The FBG structure is sensitive to temperature (e.g., the structure expands and contracts with increasing and decreasing temperature, respectively)
Implementation Method 3
a photo detector configured to generate an electrical signal based on the reflected optical signal
Data Source
AI summary
Various implementations of an apparatus for sensing one or more parameters are disclosed herein. The apparatus includes a sweeping wavelength laser configured to generate a sweeping wavelength optical signal; an optical fiber including a Fiber Bragg Grating (FBG) structure configured to sense a parameter, wherein the optical fiber is configured to receive the sweeping wavelength optical signal, wherein the FBG structure is configured to produce a reflected optical signal with a particular wavelength in response to the sweeping wavelength optical signal, and wherein the particular wavelength varies as a function of the parameter; a photo detector configured to generate an electrical signal based on the reflected optical signal; a comparator configured to generate a pulse based on a comparison of the electrical signal to a threshold; and a processor configured to generate an indication of the parameter based on the pulse. The comparator may be configured as a Schmitt trigger.