Optical Sensor Beat Frequency Reference
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Solution Overview
Problem
Optical sensor arrangements face challenges in producing multiple optical resonators with identical resonance properties, leading to inaccuracies in measuring observables such as substances or physical properties, due to production tolerances and the complexity of controlling reference resonators.
Innovation Solution
An optical sensor arrangement utilizing a light generation circuit with two distinct frequency components, where one component is fed into an optical resonator and the other travels along a separate path, coupled with an optical coupler to detect the beat frequency shift caused by changes in the resonator's optical length, thereby reducing the need for identical resonators and simplifying the setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple identical optical resonators are produced to enable accurate measurement, then measurement precision is improved, but manufacturing precision deteriorates due to production tolerances and nanostructuring variations
Solution Approach 1:
The patent uses a single optical resonator and creates a virtual copy through frequency mixing. The first light component at frequency f1 interacts with the resonator, and the second light component at frequency f2 serves as a reference. The difference frequency f2-f1 creates a beat signal that represents the resonator's resonance condition without requiring a second physical resonator, thus eliminating manufacturing variations between identical resonators.
Solution Approach 2:
The patent changes the frequency parameter of light to solve the manufacturing precision problem. By using frequency mixing between two light components (f1 and f2), the system translates the resonance detection into a beat frequency measurement. This parameter change allows the use of a single resonator while achieving the measurement function that would otherwise require multiple identical resonators.
2Measurement precision
If passive reference resonators are used to scan resonance properties, then measurement precision is improved, but device complexity increases due to sensitive temperature adjustment arrangements and control units
Solution Approach 1:
The patent replaces the mechanical temperature adjustment system with an optical frequency mixing system. Instead of using complex thermal control units and sensitive temperature adjustment arrangements to maintain reference resonators, the invention uses frequency mixing of two light components to create a beat signal that inherently provides the reference function, thereby eliminating the need for complex mechanical control systems.
Solution Approach 2:
The patent introduces a frequency mixing intermediary mechanism. The second light component at frequency f2 acts as an intermediary reference that mixes with the first light component to produce a beat signal at frequency difference f2-f1. This intermediary approach provides the necessary reference function without requiring complex temperature control systems or multiple reference resonators.
3Measurement precision
If two identical optical resonators are used with one as gauge and one as reference, then measurement precision is improved, but device complexity increases due to the difficulty of producing identical resonators
Solution Approach 1:
The patent creates a virtual reference copy through frequency mixing rather than using a second physical resonator. The beat signal generated from mixing the first light component (interacting with the resonator) and the second light component (serving as reference) provides the reference function without requiring a second resonator, thus eliminating the complexity of producing and matching identical resonators.
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 configuration enhances measurement accuracy by isolating the second light component's frequency from the resonator, allowing for precise detection of observable changes without requiring identical resonators, thus reducing production inaccuracies and complexity.
Implementation Method 1
Optical resonators have the property of allowing light of a specific frequency that represents a resonance frequency of the optical resonator (i.e., the wavelength of the light multiplied by an integer corresponds to the optical length of the optical resonator) to enter the optical resonator and interfere constructively
Implementation Method 2
light of other wavelengths enters the resonator, but interferes destructively
Implementation Method 3
when a physical condition, such as temperature or pressure, of the surrounding medium changes or a substance, such as a chemical compound or a biological substance, attaches to at least one of the surfaces of the resonator, the optical length of the optical resonator changes, i.e., the resonance frequency of the optical resonator is shifted
Implementation Method 4
a light generation circuit for generating a first light component of a first frequency and a second light component of a second frequency
Implementation Method 5
a detector unit for detecting a first and second light component from the light generation circuit which has traveled through the optical resonance circuit
Data Source
Figure 1
Figure 2~5
Figure 3
AI summary
The application relates to an optical sensor arrangement (1; 100) for measuring an observable. The arrangement comprising a light generation circuit (2; 102) for generating a first and a second light component; an optical resonance circuit (3; 103) including at least a first optical resonator (34; 134) having a first optical length and a drop port (37; 137), where the first optical length is variable depending on the observable; an optical coupler (4) coupled to the optical resonance circuit, where the drop port of the first optical resonator is coupled to the optical coupler and the coupler is configured for superposing the first and second light components; and a detector unit (5; 105) coupled to the optical coupler, receiving the superposed first and second light components and configured for outputting an output signal (50) representing a frequency difference between the first and second light components.