Optical Interference Temperature Sensor for Milli-Kelvin Precision
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Solution Overview
Problem
Existing temperature sensors, such as platinum sensors, drift over time and are affected by environmental conditions like airflows and pressure changes, making them unreliable for precise temperature measurements at milli-Kelvin precision.
Innovation Solution
A temperature sensor utilizing two optical waveguides with different temperature-dependent optical properties, where the measurement light is split and superimposed after passing through each waveguide, allowing for accurate temperature measurement independent of environmental conditions by leveraging the distinct temperature responses of the waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If platinum temperature sensors are used for highly accurate temperature measurement, then temperature measurement precision is improved, but the sensors drift over time and are affected by environmental conditions such as airflows and pressure changes
Solution Approach 1:
The patent replaces the electrical resistance-based measurement system with an optical interference system. Two optical waveguides with different temperature dependencies are used to create an interferometric measurement that is immune to environmental disturbances. The measurement light passes through both waveguides and the interference pattern is detected, providing stable long-term temperature measurement without the drift problems of platinum sensors.
Solution Approach 2:
The patent changes the measurement parameter from electrical resistance to optical path length. By using optical waveguides with different temperature dependencies and measuring the interference pattern of light passing through them, the system achieves temperature measurement that is independent of environmental conditions like pressure and airflow, while maintaining high precision and long-term stability.
2Measurement precision
If platinum temperature sensors are used, then temperature measurement capability is achieved, but the sensors react to changes in flow speed of surrounding air due to self-heating
Solution Approach 1:
The patent replaces the electrical heating and resistance measurement system with an optical system. The measurement light passes through the optical waveguides without significant energy transfer to the surrounding air, eliminating the self-heating effect that plagues electrical temperature sensors. The optical interference measurement provides temperature data without disturbing the thermal environment.
3Reliability
If optical waveguides with different temperature dependencies are used, then long-term stability is improved, but device complexity increases due to multiple waveguides and optical components
Solution Approach 1:
The patent divides the measurement function into two separate optical waveguides, each with different temperature dependencies. This segmentation allows the system to measure temperature through interference while being insensitive to environmental disturbances. The two waveguides work together to provide stable long-term measurement despite the increased component count.
Solution Approach 2:
The patent combines the two optical waveguides into a single interferometric measurement system. By merging the light paths and detecting the interference pattern, the system achieves temperature measurement with high long-term stability. The combination of waveguides with different temperature dependencies creates a measurement that cancels out environmental effects.
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
Enables highly accurate and stable long-term temperature measurement with minimal aging effects, unaffected by pressure fluctuations and airflows, achieving milli-Kelvin precision.
Implementation Method 1
a monochromatic frequency-stabilised laser for generating the measurement light
Implementation Method 2
the measurement light portions are superimposed after passing through the optical waveguides
Implementation Method 3
two optical waveguides which are arranged such that they respectively receive a measurement light portion
Data Source
AI summary
A temperature sensor is provided which comprises a measurement light source for generating measurement light and two optical waveguides. The two optical waveguides are arranged such that they respectively receive a measurement light portion of the measurement light and that the measurement light portions are superimposed after passing through the optical waveguides. Furthermore, the two optical waveguides have an optical property with different temperature dependency.