Wavelength Determining Device Using Interference Fringes and Correction Coefficients
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Solution Overview
Problem
Conventional Michelson interferometers face challenges in accurately measuring light wavelengths due to air refractive index dispersion, which is influenced by temperature, pressure, humidity, and CO2 concentration, and errors occur if optical element alignment is off, leading to insufficient correction of wavelength measurement errors.
Innovation Solution
A wavelength determining apparatus that includes a reference wavelength measuring unit, an input light wavelength measuring unit, a correction coefficient determining unit, and an input light wavelength correcting unit, which uses multiple reference wavelengths and interference fringe counting to calculate and apply a correction coefficient to accurately measure the wavelength of input light, accounting for air refractive index and optical path differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correction coefficient based on air refractive index is applied, then the measurement precision is improved, but the device complexity increases due to multiple sensors and calculations
Solution Approach 1:
The patent changes the parameter of refractive index correction by using a predetermined correction value stored in memory rather than calculating it in real-time from multiple environmental parameters. This reduces device complexity while maintaining measurement precision through pre-computed correction values.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing correction values for different wavelengths in a memory device before actual measurement. This eliminates the need for complex real-time calculations and multiple sensors during measurement, reducing device complexity while improving precision.
2Measurement precision
If multiple environmental parameters are measured for correction, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent pre-calculates correction values based on refractive index variations due to environmental parameters before measurement, storing them in memory. This eliminates the need for multiple environmental sensors during actual measurement, reducing device complexity while maintaining precision through pre-computed corrections.
Solution Approach 2:
The patent extracts only the essential correction factor (refractive index effect) from the complex set of environmental parameters, using a predetermined correction value that accounts for refractive index without requiring measurement of temperature, pressure, humidity, and CO2 concentration separately.
3Adaptability or versatility
If the wavelength of input light deviates from reference wavelength, then the adaptability is improved, but the measurement precision deteriorates due to insufficient correction
Solution Approach 1:
The patent makes the wavelength determination device universal by enabling accurate measurement of input light across different wavelengths through the predetermined correction value. The correction mechanism works for any wavelength within the measurement range, not just for wavelengths close to the reference wavelength, improving both adaptability and precision.
Solution Approach 2:
The patent addresses wavelength deviation by applying a predetermined correction value that compensates for refractive index effects at the specific wavelength being measured. This allows accurate measurement across a range of wavelengths by selecting the appropriate correction value, improving both adaptability and precision.
4Ease of operation
If optical element alignment is not perfect, then the ease of operation is improved, but the measurement precision deteriorates
Solution Approach 1:
The patent converts the harmful effect of misalignment-induced measurement errors into a beneficial correction process. By applying a predetermined correction value that accounts for systematic errors including alignment deviations, the system achieves high precision without requiring perfect alignment, thus improving both ease of operation and measurement precision.
Solution Approach 2:
The patent implements a feedback mechanism where the predetermined correction value compensates for known errors including alignment deviations. The correction process feedback-adjusts the measured wavelength to account for systematic errors, maintaining high precision even when alignment is not perfect.
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 enables precise measurement of light wavelengths by correcting for air refractive index variations and optical alignment errors, improving the accuracy of wavelength determination even when the input light deviates from the reference wavelength.
Implementation Method 1
a Michelson interferometer is configured to generate a predetermined optical path difference L... the number of resulting interference fringes is A... the number of resulting interference fringes is B
Data Source
AI summary
There is provided a wavelength determining device including a reference wavelength measuring section 42 that, based upon a number A of interference fringes generated by an optical path difference of first reference wavelength light (wavelength: λ1) and a number C of interference fringes generated by the optical path difference of second reference wavelength light (wavelength: λ2), measures the wavelength of the second reference wavelength light, an input light wavelength measuring section 44, based upon the number A of the interference fringes generated by the optical path difference of the first reference wavelength light (wavelength: λ1) and a number B of interference fringes generated by the optical path difference of input light (wavelength: λx), measures the wavelength of the input light, a correction coefficient determining section 46 that determines a second correction coefficient k based upon the measured wavelength λc of the second reference wavelength light and the measured wavelength λm of the input light, and an input light wavelength correcting section 48 that corrects the measured wavelength of the input light by multiplying the measured wavelength λm of the input light by the second correction coefficient k, in order to correctly measure the wavelength λx(=k·λm) of the input light.