Optical Sensor Arrangement Using Orthogonal Modes for Precision Measurement
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Solution Overview
Problem
Existing optical sensor arrangements for measuring observables are complex and not cost-efficient, making them difficult to produce and use effectively, especially in scanning the resonance properties of materials with high accuracy in the picometer or sub-picometer region.
Innovation Solution
An optical sensor arrangement that uses a tunable light source and optical resonator with differing optical lengths for orthogonal modes, allowing for variable optical lengths based on the observable, which differ in their dependence on the presence of substances, enabling measurement of frequency differences to detect the presence of observables without the need for complex reference resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive reference resonators with sensitive temperature adjustment arrangements are used to scan resonance properties, then measurement accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent combines the reference resonator and measurement resonator into a single integrated optical resonator structure that supports multiple orthogonal modes. Instead of using separate reference resonators with complex temperature control, the invention uses a single resonator where different modes serve as reference and measurement channels, eliminating the need for complex temperature adjustment arrangements while maintaining measurement accuracy.
Solution Approach 2:
The optical resonator is designed to perform multiple functions simultaneously: it acts as both a reference resonator and a measurement resonator by supporting orthogonal modes with different optical lengths. This multi-functionality eliminates the need for separate reference resonators and their associated complex control systems, reducing device complexity while maintaining measurement precision.
2Measurement precision
If multiple microrings with identical resonance properties are produced, then measurement accuracy is improved, but manufacturing difficulty increases due to temperature dependency
Solution Approach 1:
Instead of producing multiple separate microrings with identical resonance properties, the patent merges the reference and measurement functions into a single microring resonator that supports multiple orthogonal modes. This approach eliminates the manufacturing difficulty of producing identical separate microrings while achieving the same measurement precision through modal differentiation within one resonator.
3Device complexity
If a single optical resonator with orthogonal modes is used, then device complexity is reduced, but the ability to scan resonance properties with high accuracy is compromised
Solution Approach 1:
The patent exploits the dynamic properties of orthogonal modes within a single resonator, where each mode has a distinct optical length that responds differently to changes in the measurement parameter. By tuning the resonator or using broadband excitation, the system can scan through resonance frequencies and detect shifts with high accuracy, maintaining measurement precision while reducing device complexity.
Solution Approach 2:
The invention changes the operational parameters of the single resonator by utilizing orthogonal modes with different optical lengths. These parameter differences allow the system to distinguish between reference and measurement signals, enabling accurate resonance frequency detection without requiring multiple separate resonators or complex control arrangements.
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 simplifies the optical sensor arrangement, allowing for cost-efficient measurement of observables with high accuracy, enabling detection of small variations in resonance frequencies, such as those due to pressure, temperature, or molecular presence, by scanning through frequency intervals and utilizing a single optical resonator with an active layer for selective absorption.
Implementation Method 1
Optical resonators such as optical microrings are very sensitive optical sensor types that use the evanescent electromagnetic field travelling there through for scanning a surface
Implementation Method 2
scan resonance properties of different materials
Data Source
Figure 1a~2a
Figure 2b~2c
Figure 3~4
AI summary
The invention relates to an optical sensor arrangement (1; 10; 40; 60) for measuring an observable comprising: at least one light source (2; 11, 12; 41, 42; 62, 63, 64) for generating a first light component of a first frequency comprising a first mode and a second light component of a second frequency comprising a second mode orthogonal to said first mode; an optical resonator (4; 17; 45; 69) having differing optical lengths for the first and second modes, at least one of the optical lengths being variable depending on the observable and a dependence of the respective optical length being different for said first and second modes, wherein the at least one light source is optically coupled to the optical resonator for feeding the two light components into the optical resonator; and a detector unit (6; 23 52; 74) being coupled to the optical resonator for coupling out the two light components and being configured for detecting a frequency difference between a resonance frequency of the optical resonator for the first mode and a resonance frequency of the optical resonator for the second mode. Furthermore, the invention relates to a method for measuring an observable by means of an optical sensor arrangement (1; 10; 40; 60) of this kind.