Fiber Optic Temperature Sensing with Regenerated Time-of-Flight Pulses
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Solution Overview
Problem
Conventional fiber optic temperature sensors are unsuitable for harsh industrial environments due to their reliance on complex and expensive spectrum analyzers, making them unreliable and costly, and they lack the necessary accuracy and immunity to electromagnetic interference.
Innovation Solution
A novel fiber optic temperature sensor design that utilizes a hybrid optical and electronic loop with an analog optical-to-electrical-to-optical regenerator to enhance time-of-flight measurement sensitivity, achieving better than 1°C accuracy by regenerating optical pulses multiple times within a fiber coil, thereby reducing manufacturing costs and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fiber optic temperature sensors use spectrum analyzers for measurement, then temperature measurement capability is achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts and removes the complex spectrum analyzer component from the temperature sensing system. Instead of using a spectrum analyzer to measure temperature, the invention uses a simplified setup with a laser diode, optical fiber sensor, and basic detection electronics, thereby achieving temperature measurement without the complex and expensive spectrum analyzer hardware
Solution Approach 2:
The patent uses optical pulse time-of-flight measurement as a simplified copy/alternative to spectrum analysis. By measuring the time it takes for optical pulses to travel through the fiber and back, the system achieves temperature sensing through a much simpler method that doesn't require complex spectral analysis equipment
2Measurement precision
If conventional fiber optic temperature sensors are designed for high accuracy, then measurement precision improves, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent employs inexpensive, commercially available components such as standard laser diodes, off-the-shelf optical fibers, and basic photodetectors instead of expensive specialized high-accuracy components. This approach achieves sufficient measurement accuracy for industrial applications while dramatically reducing manufacturing costs and simplifying the supply chain
3Measurement precision
If conventional temperature sensors are used in harsh industrial environments, then temperature measurement is achieved, but reliability decreases due to electromagnetic interference
Solution Approach 1:
The patent replaces conventional electrical-based temperature sensors with an all-optical sensing system. By using optical fibers to transmit sensing information and optical pulses for measurement, the system achieves immunity to electromagnetic interference that plagues traditional electrical sensors in harsh industrial environments with strong EMI
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
The sensor achieves enhanced temperature measurement accuracy and reliability, with sensitivity improved by regenerating optical pulses multiple times, making it suitable for industrial applications with immunity to electromagnetic interference and reduced manufacturing costs.
Implementation Method 1
a photodetector, the photodetector configured to: detect the initial optical pulse and the subsequently regenerated optical pulses
Implementation Method 2
an optical fiber probe comprising a length of optical fiber having an optical input and an optical output
Implementation Method 3
the microcontroller is configured to process the digital signal based on its time of flight variation to determine a temperature change
Data Source
AI summary
A novel detection scheme and all fiber optic temperature sensor is disclosed. The apparatus comprising a sensing loop; a laser diode driver; a coupler; a first photodetector coupled to the coupler output to produce a current; an amplifier to convert and amplify the current to voltage; an A/D converter to convert the voltage to digital signal; an AOEO regenerator to convert coupler optical output to electronic signal while preserving timing information and electronic signal to regenerated optical signal; a timer to control AOEO delay time; optical fiber probe; and microcontroller coupled to laser diode driver, A/D converter, and timer; and configured to control first optical signal timing and AOEO delay time; and configured to process digital signal based on its time of flight variation to determine a temperature change, and wherein sensitivity increases with increasing optical fiber length and/or number of regenerated optical signals. Other embodiments are described and claimed.