Defect-Emitting Optical Fiber for Distributed Temperature Sensing
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Solution Overview
Problem
Existing optical temperature sensors, particularly those using rare earth-doped fibers, suffer from low sensitivity and are limited to point sensing, lacking a robust framework for distributed temperature sensing.
Innovation Solution
Development of alkaline-earth fluorosilicate optical fibers with defects that emit intense green light when pumped by infrared radiation, allowing for visual temperature sensing and distributed temperature measurement through changes in light intensity and upper state lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rare earth-doped optical fibers are used for luminescence-based thermometry, then temperature sensing capability is achieved, but sensitivity to temperature is low
Solution Approach 1:
The patent changes the material composition parameters by using alkaline-earth fluorosilicate glass instead of traditional rare earth-doped materials. This compositional parameter change results in defects with much higher temperature sensitivity, achieving 10 times greater sensitivity compared to conventional rare earth-doped fibers while maintaining reliable sensing performance through the material's inherent photoluminescence properties.
2Measurement precision
If optically pumped quantum dots are used for temperature sensing, then point sensing capability is achieved, but distributed sensing capability is lost
Solution Approach 1:
The optical fiber is designed to perform multiple functions simultaneously: it serves as both a light transmission medium and a distributed temperature sensor along its entire length. The alkaline-earth fluorosilicate glass defects provide photoluminescence throughout the fiber, enabling distributed temperature measurement across the whole fiber rather than at a single point, thus achieving versatility in sensing applications.
3Use of energy by moving object
If conventional optical fibers are used, then standard optical transmission is achieved, but temperature sensing sensitivity is insufficient
Solution Approach 1:
The patent creates a composite material system by incorporating alkaline-earth fluorosilicate glass with specific defect structures into the optical fiber core. This composite approach combines the optical transmission properties of standard fiber with the temperature-sensitive photoluminescence of the fluorosilicate glass defects, achieving both efficient optical transmission and high temperature sensing sensitivity simultaneously.
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 fibers provide a sensitive and reversible temperature sensing mechanism capable of detecting temperatures from -269°C to 200°C with high spatial resolution, enabling imaging-based distributed sensing.
Implementation Method 1
When pumped with infrared light, the defects emit green light at an intensity dependent on a temperature of the optical fiber
Implementation Method 2
Because the emission is a very strong function of temperature, the optical fibers may be employed for optical thermometry. As shown in the examples below, the intense green emission can be generated by IR pumping with commercial, off-the-shelf laser diodes operating at a power level less than 1 W
Data Source
AI summary
A method of measuring temperature includes positioning an optical fiber in contact with an object or in an environment having a temperature to be determined, where the optical fiber comprises a core surrounded by a cladding; the core comprises an alkaline-earth fluorosilicate glass including defects, and the cladding comprises a silica glass. Infrared light is supplied to the optical fiber, thereby electronically exciting the defects. Green light emitted from the defects is detected, and an intensity value of the green light is obtained and converted to a temperature value for the optical fiber, whereby the temperature of the object or environment is determined. The green light may be detected along a length of the optical fiber, and a plurality of intensity values may be converted to a plurality of temperature values along the fiber length, thereby obtaining a distributed measurement of the temperature of the object or environment.