Distributed Fiber Strain Sensing With Light Source Error Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing distributed strain sensing systems using optical fibers are affected by errors due to changes in the light source, which can lead to inaccurate strain measurements.
Innovation Solution
A distributed strain sensing system that includes an optical modulator to emit light pulses with varying frequencies, an optical circulator to direct light, an optical fiber with standard and sensing fibers, an optical receiver to analyze Rayleigh scattered light, and an optical source error compensator to correct for errors caused by light source deviations, using equations to calculate accurate strain measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a distributed strain sensing system uses optical fiber sensors to monitor structures, then wide-area coverage and high-sensitivity strain measurement are achieved, but measurement accuracy deteriorates due to errors caused by light source changes
Solution Approach 1:
The system performs preliminary measurements using a standard sensing optical fiber housed in an environmental protection case to establish baseline characteristics before actual strain sensing. This preliminary action captures the light source characteristics under controlled conditions, which are then used to compensate for light source variations during subsequent measurements, thereby maintaining measurement accuracy across wide areas.
Solution Approach 2:
A standard sensing optical fiber served as an intermediary element between the light source and the measurement system. This standard fiber, protected from environmental factors, acts as a reference that mediates the relationship between light source variations and strain measurements, enabling error compensation and improving overall measurement precision across the distributed sensing network.
2Measurement precision
If the system uses a standard sensing optical fiber housed in an environmental protection case, then light source error compensation is enabled, but device complexity increases
Solution Approach 1:
The standard sensing optical fiber housed in the environmental protection case serves multiple functions: it acts as a reference for light source characterization, provides a baseline for error compensation, and maintains stable optical properties under controlled conditions. This multi-functionality reduces the need for separate calibration devices, thereby limiting the increase in system complexity while improving measurement precision.
3Area of stationary object
If optical modulator emits light pulses with N different optical frequencies, then strain measurement at multiple points is enabled, but use of energy increases
Solution Approach 1:
The optical modulator emits light pulses with N different optical frequencies in a periodic, repetitive manner. This periodic action allows the system to cycle through multiple frequencies over time, enabling strain measurement at multiple points along the optical fiber while managing energy consumption through time-multiplexed operation rather than simultaneous multi-frequency emission.
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 system provides precise strain measurements by compensating for errors due to light source variations, ensuring accurate strain detection in structures like tunnels and submarine cables.
Implementation Method 1
The optical circulator is configured to receive Rayleigh scattered light reflected back from different points of the optical fiber via the second port and output the received light via the third port
Data Source
AI summary
Provided is a method for providing a strain measurement value in a sensing optical fiber. The method may include outputting light to an optical fiber, in which the optical fiber includes a standard sensing optical fiber and a sensing optical fiber extending from the standard sensing optical fiber, in which the standard sensing optical fiber is accommodated inside an external environmental protection case, providing a strain measurement value in the sensing optical fiber based on Rayleigh scattered light reflected back from points of the optical fiber, and providing a final strain measurement value by compensating for an error caused by a change in light source in the strain measurement value in the sensing optical fiber.