Brillouin Optical Sensing Device with Mode Switching for Fiber Failure Tolerance
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Solution Overview
Problem
Existing Brillouin optical time domain analyzers face challenges in maintaining high sensitivity and accuracy for distributed temperature and strain measurements, especially when sensing optical fibers are degraded or breached, limiting their ability to function in severe environments and embedded structures.
Innovation Solution
A Brillouin optical distributed sensing device that can switch between stimulated and spontaneous Brillouin scattering configurations, allowing measurements with the same components by routing optical paths differently, enabling operation even with damaged sensors and providing high sensitivity and accuracy without the need for two-side access to the sensing fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stimulated Brillouin scattering measurements are used, then measurement sensitivity and accuracy are improved, but device complexity increases due to requiring two-side access to the sensing fiber
Solution Approach 1:
The device is designed to perform both stimulated Brillouin scattering measurements (for high precision) and spontaneous Brillouin scattering measurements (for simplicity and single-side access). The same basic device structure can switch between these two measurement modes, making it universally applicable to different sensing scenarios and fiber configurations without requiring separate specialized devices for each mode.
2Ease of operation
If spontaneous Brillouin scattering measurements are used, then ease of operation is improved with single-side access, but measurement sensitivity deteriorates
Solution Approach 1:
The device dynamically switches between stimulated and spontaneous Brillouin scattering measurement modes based on the specific application requirements and fiber condition. This dynamic adaptability allows the system to optimize between ease of operation and measurement sensitivity by selecting the appropriate mode for each scenario, whether single-side access is needed or high precision measurements are required.
3Reliability
If the sensing optical fiber is breached or degraded, then reliability deteriorates, but the ability to continue measurements is lost
Solution Approach 1:
The device changes the measurement parameter mode by switching between stimulated and spontaneous Brillouin scattering techniques. When the sensing fiber is breached or degraded, the system can transition to spontaneous scattering mode which is more tolerant of fiber damage, allowing measurements to continue albeit with reduced precision. This parameter change enables the system to maintain productivity despite fiber degradation.
4Measurement precision
If two separate devices are used for stimulated and spontaneous measurements, then measurement precision is improved for each mode, but device complexity and cost increase
Solution Approach 1:
The invention merges the capabilities of stimulated and spontaneous Brillouin scattering measurement devices into a single integrated device. By combining the necessary components (light sources, detectors, signal processing units) and adding a mode-switching mechanism, the system achieves both high-precision stimulated scattering measurements and easier spontaneous scattering measurements in one device, thereby reducing overall device complexity and cost while maintaining the measurement precision benefits of both modes.
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 device achieves high sensitivity and accuracy in temperature and strain measurements, allowing for continuous data collection even if the sensing optical fiber is breached, and reduces complexity and cost by using the same components for both configurations, optimizing detection sensitivity and maintaining functionality in harsh environments.
Implementation Method 1
Brillouin scattering occurs when a light wave propagating in a medium (such as an optical fiber) interacts with time-dependent density variations of the medium. These density variations may be due for instance to acoustic waves or phonons propagating in the medium, and they modulate the index of refraction.
Implementation Method 2
stimulated Brillouin scattering measurements, in which case the systems are usually referred to as Brillouin Optical Time Domain Analyzers (BOTDA)
Implementation Method 3
Since acoustic waves propagates at the speed of sound in the medium, deflected light is also subjected to a Doppler shift, so its frequency changes.
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~6
AI summary
The present invention concerns a Brillouin optical distributed sensing device (1), comprising means (2, 3, 4, 9) for generating an optical pulsed signal and an optical probe signal, and circulation means (10) for directing said optical pulsed signal to a sensing optical fiber (21) and for directing an optical measurement signal with Brillouin scattering information arising from said sensing optical fiber (21) toward detection means (18, 19), the device further comprising optical routing means (5) for configuring the device (1) so as to allow generating: (i) according to a first configuration, an optical measurement signal with stimulated Brillouin scattering information resulting from the interaction of the optical pulsed signal and an optical probe signal propagating in said sensing optical fiber (21) in a direction opposite to the optical pulsed signal, or (ii) according to a second configuration, an optical measurement signal with spontaneous Brillouin scattering information resulting from the propagation of the optical pulsed signal in the sensing optical fiber (21). The present invention concerns also a Brillouin optical distributed sensing method.