Multimode Fiber Sensor for Multi-Parameter Measurement
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Solution Overview
Problem
Existing solutions for measuring multiple physical parameters at a single point using optical fibers are complex, require multiple fibers, and are limited in their ability to simultaneously measure a variety of parameters.
Innovation Solution
A system utilizing a single multimode optical fiber with a measurement section that exploits different signal propagation modes to measure multiple physical parameters. This system includes a light source, a multimode measurement optical fiber, a detection device, and an optical module that generates and transfers optical signals in distinct propagation modes to determine physical parameters by solving a system of equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple optical fibers are used to measure multiple physical parameters, then measurement capability is improved, but device complexity and integration difficulty increase
Solution Approach 1:
The patent segments the measurement function by utilizing different propagation modes (spatial modes and polarization modes) within a single optical fiber. Each mode provides independent sensitivity to different physical parameters, allowing one fiber to perform multiple measurement functions that would traditionally require multiple separate fibers.
Solution Approach 2:
The patent makes the single optical fiber universal by enabling it to measure multiple physical parameters simultaneously through mode differentiation. The fiber acts as a multi-functional sensor where different modes (e.g., HE11a, HE11b, TM01, TE01) provide distinct sensitivity characteristics for temperature, strain, and other parameters.
2Adaptability or versatility
If polarization discrimination is used to measure multiple parameters, then measurement capability is improved, but implementation complexity increases
Solution Approach 1:
The patent changes the parameter of polarization state to differentiate between multiple physical parameters. By measuring the polarization characteristics of light in different modes (TE, TM, HE modes), the system can distinguish between temperature, strain, and other parameters without requiring complex mechanical arrangements.
3Adaptability or versatility
If multicore optical fiber is used with different sensitivities, then measurement capability is improved, but connection and interfacing complexity increases
Solution Approach 1:
The patent merges multiple measurement functions into a single optical fiber rather than using separate multicore fibers. This consolidation eliminates the need for complex connections between multiple fiber cores and simplifies the overall system architecture while maintaining the ability to measure multiple parameters simultaneously.
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 the compact and simple measurement of multiple physical parameters using a single optical fiber, improving integration and mounting complexity compared to traditional methods, while maintaining high accuracy through the differentiation of signal propagation modes.
Implementation Method 1
A Bragg grating fiber-optic sensor comprises an optical fiber including at least one Bragg grating inscribed on a section of the optical fiber, referred to as the measurement section. Depending on the thermomechanical stresses applied to this section, the patterns of the Bragg grating are more or less spaced apart from one another. The Bragg wavelength, for which a light beam is reflected, therefore differs according to these stresses.
Implementation Method 2
a multimode measurement optical fiber arranged to transport optical signals in at least M second predetermined propagation modes that are distinct from one another
Implementation Method 3
a detection device arranged to measure wavelengths of the optical signals reflected by the measurement section
Data Source
AI summary
In the field of measuring physical parameters with a multimode optical fiber, a system for measuring P physical parameters at one or more measurement points has one or more multimode optical fibers. The system includes: a light source generating a source optical signal, a multimode measurement optical fiber transporting optical signals in at least M distinct second predetermined propagation modes, M being an integer greater than or equal to P, the measurement optical fiber including a measurement section reflecting the optical signals with a wavelength variable according to physical parameters to be measured, a detection device measuring wavelengths of the optical signals reflected by the measurement section, and an optical module generating M signals from the source optical signal, the M signals each being injected into the measurement optical fiber to propagate in one of the modes, the optical module also transferring the optical signals reflected toward the detection device.