Michelson Fiber Sensor Fringe Contrast Detection
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Solution Overview
Problem
Current Michelson optical fiber temperature sensors face challenges in achieving high precision and sensitivity due to complex and costly signal demodulation methods, especially when using narrowband laser light sources, and often require additional precision instruments, limiting their widespread adoption for temperature measurement.
Innovation Solution
A Michelson interference optical fiber temperature sensor design that includes a light source, optical fiber coupler, coarse wavelength division multiplexer, photodetectors, processing circuit, and semiconductor materials, which simplifies signal demodulation by detecting contrast changes in interference fringes, eliminating the need for other precision instruments and achieving high precision temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrowband laser light source is used for measurement, then measurement sensitivity is improved, but signal demodulation complexity increases and requires high technical requirements
Solution Approach 1:
The patent changes the detection parameter from fringe position/movement to fringe contrast (visibility). By using a broadband light source and detecting contrast changes in the interference pattern, the system achieves temperature measurement without requiring complex phase demodulation techniques, thus resolving the contradiction between sensitivity and demodulation complexity
Solution Approach 2:
The patent replaces expensive narrowband laser sources with inexpensive broadband light sources. This substitution eliminates the need for complex signal demodulation systems while maintaining measurement capability, effectively reducing both device complexity and cost
2Device complexity
If broadband light source is used for measurement, then signal demodulation is simplified, but measurement accuracy decreases due to low interference effect
Solution Approach 1:
The patent detects contrast changes in the interference pattern rather than relying on fringe position or intensity variations. This parameter change enables accurate temperature measurement using broadband light sources, as the contrast variation is directly related to temperature-induced changes in the semiconductor's optical properties, thereby maintaining accuracy while using simple demodulation
3Measurement precision
If interference peak tracking method is used, then parameter measurement is achieved, but measurement accuracy is low and system complexity increases when using precision instruments
Solution Approach 1:
The patent extracts only the contrast information from the interference pattern and ignores other complex parameters like phase and position. By focusing solely on contrast changes, the system achieves temperature measurement without requiring precision instruments for peak tracking, thus reducing system complexity and cost while maintaining measurement capability
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 sensor provides a simple, fast, and cost-effective solution for high-sensitivity and high-precision temperature measurement by utilizing the contrast change of interference fringes, stabilizing signal processing, and eliminating the influence of light source fluctuations and optical fiber loss, thus overcoming existing limitations.
Implementation Method 1
a light source, an optical fiber coupler
Implementation Method 2
The optical fiber coupler is configured to couple and distribute the optical signals transmitted by the light source and the optical signals returned by the first optical fiber and the second optical fiber
Implementation Method 3
The coarse wavelength division multiplexer is configured to demultiplex the optical signals returned by the first optical fiber and the second optical fiber to obtain a broadband optical signal and a narrowband optical signal
Implementation Method 4
The first photodetector and the second photodetector are respectively configured to receive the broadband optical signal and the narrowband optical signal obtained by the demultiplexing of the coarse wavelength division multiplexer
Implementation Method 5
a material of the semiconductor is gallium arsenide, or other semiconductor materials with a change of one of transmissivity and absorbance greater than that of the gallium arsenide when affected by a change in ambient temperature at a same wavelength of incident light
Implementation Method 6
The processing circuit is configured to process the broadband optical signal and the narrowband optical signal received by the first photodetector and the second photodetector, detect a contrast change of the interference fringes, and demodulate, based on the contrast change of the interference fringes, a temperature detection result
Data Source
AI summary
A Michelson interference optical fiber temperature sensor for detecting fringe contrast change is provided. It includes a light source, an optical fiber coupler connected to a first optical fiber and a second optical fiber, a coarse wavelength division multiplexer, a first photodetector, a second photodetector, a display device, and a processing circuit connected to the display device. The light source, optical fiber coupler and coarse wavelength division multiplexer are connected sequentially in that order. The coarse wavelength division multiplexer is connected to the first photodetector and the second photodetector individually. The first photodetector and the second photodetector are connected to the processing circuit. An end of the first optical fiber or the second optical fiber facing away from the optical fiber coupler is connected to a semiconductor. It has advantages of simple and fast manufacturing process, safe and reliable sensor, stable signal, low cost, high sensitivity and high precision.