Optical Sensor System Using Time Delay Line for Multi-Sensor Coupling
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Solution Overview
Problem
Existing optical sensing methods for environmental parameters along long optical fibers are time-consuming or require low-dispersion fibers, which are inadequate for coupling multiple sensors effectively.
Innovation Solution
An optical system comprising an optical pulse generator, a pulse splitter, a sensing arm with an emission sensor, a reference arm with an emission artefact, and a time delay line, which generates and splits excitation and reference pulses at different wavelengths for measuring environmental parameters through optical energy detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time evolution techniques such as fluorescence lifetime technique or ring down spectroscopy are used to measure spectral loss, then measurement accuracy is improved, but measurement time increases significantly
Solution Approach 1:
The patent employs periodic pulsed laser excitation instead of continuous illumination, allowing the system to measure spectral loss through time-resolved detection of periodic signal returns. This periodic action enables accurate spectral loss measurement while maintaining fast measurement speeds by synchronizing detection with the pulse repetition rate.
Solution Approach 2:
The patent performs preliminary calibration by measuring the spectral loss of reference fibers with known characteristics before measuring unknown samples. This preliminary action establishes a baseline that enables rapid subsequent measurements without requiring time-consuming absolute measurements each time, thus improving both accuracy and speed.
2Productivity
If low-dispersion fibers are used to reduce time evolution effects, then measurement speed is improved, but coupling capability for multiple sensors deteriorates
Solution Approach 1:
The patent segments the optical fiber system into multiple discrete sensing points along the fiber length, allowing independent measurement at each location. This segmentation enables effective coupling of multiple sensors on standard dispersion fibers while maintaining measurement speed through time-resolved detection that distinguishes signals from different spatial locations.
Solution Approach 2:
The patent adds the time dimension to the measurement by using time-resolved detection of backscattered light. This temporal dimension allows the system to resolve signals from multiple sensors along the fiber without requiring special low-dispersion fibers, thus enabling multi-sensor coupling while maintaining measurement speed on standard fibers.
3Measurement precision
If spectral loss measurement is performed at multiple wavelengths, then environmental parameter sensing accuracy is improved, but system complexity increases
Solution Approach 1:
The patent employs a single pulsed laser source that can operate at multiple wavelengths, making the system universal for measuring various environmental parameters (temperature, strain, etc.) that affect spectral loss differently at different wavelengths. This multi-functionality approach reduces system complexity compared to using separate lasers for each wavelength.
Solution Approach 2:
The patent combines multiple wavelength measurements into a single integrated system using a pulsed laser source that emits at multiple wavelengths and a time-resolved detection system that captures signals from all wavelengths simultaneously. This merging approach measures multiple environmental parameters in one operation, improving accuracy while reducing overall system complexity.
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 system enables efficient and accurate remote sensing of environmental parameters by minimizing time and fiber dispersion issues, allowing for effective coupling of multiple sensors along long optical fibers.
Implementation Method 1
an optical emission sensor for sensing the environmental parameter of the sample, the optical emission sensor generating at least one first measurement pulse, each first measurement pulse having a respective measurement wavelength different from the excitation wavelength
Implementation Method 2
the reference arm comprising an emission artefact adapted to convert the reference pulse into a at least one second measurement pulse each having the respective measurement wavelength
Data Source
AI summary
An optical system for sensing an environmental parameter, comprising: an optical pulse generator for generating an excitation pulse; a pulse splitter for splitting the excitation pulse into a sensing pulse and a reference pulse; a sensing arm for receiving the sensing pulse, the sensing arm comprising an emission sensor for sensing the environmental parameter, the optical emission sensor generating a first measurement pulse having a measurement wavelength; a reference arm for receiving the reference pulse, the reference arm comprising an emission artifact adapted to convert the reference pulse into a second measurement pulse having the measurement wavelength; a time delay line for delaying a relative propagation of the measurement pulses; a light detector for measuring an optical energy of the first and second measurement pulses; and an optical link for optically connecting the pulse generator to the pulse splitter, and the sensing and reference arms to the light detector.