Optical Fiber Underground Vibration Detection System
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Solution Overview
Problem
Existing optical fiber sensing systems for detecting underground tunnel digging activities face challenges in wide-area monitoring due to wide spacings between sensors, leading to potential undetected vibrations and increased costs associated with specialized sensor structures.
Innovation Solution
An optical fiber sensing system that detects vibrations and acquires optical signals to identify suspicious actions based on vibration patterns, allowing for cost-effective monitoring across wide areas without the need for specialized sensor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If vibration sensors are provided on the optical fiber at wide spacings for wide-area monitoring, then the monitoring area is expanded, but vibrations in some parts of the monitoring area cannot be detected
Solution Approach 1:
The patent replaces the mechanical vibration sensor system with an optical-based detection system. Instead of using physical sensors that require wide spacing, the system uses an optical fiber with a light source and photodetector to detect vibrations through optical signal changes. This substitution allows for continuous monitoring along the entire optical fiber length, eliminating the spacing problem while maintaining wide-area coverage.
Solution Approach 2:
The optical fiber serves multiple functions: it acts as both the transmission medium for light and the sensing element for vibration detection. The single optical fiber structure provides continuous monitoring capability across the entire monitoring area without requiring additional sensor components, achieving both wide coverage and reliable detection simultaneously.
2Reliability
If vibration sensors are provided on the optical fiber, then underground vibrations can be detected, but the cost increases due to the special sensor structure
Solution Approach 1:
The patent eliminates the need for mechanical vibration sensors by using an all-optical detection system. The system employs a light source, optical fiber, and photodetector to convert mechanical vibrations into optical signal variations, which are then detected electronically. This substitution removes the expensive sensor components while maintaining detection capability.
Solution Approach 2:
Instead of using physical sensors that directly contact the optical fiber, the system creates an optical copy or representation of the vibration information through light modulation. The vibrations are transduced into optical signal variations that carry the same information, allowing detection without physical sensor attachment and reducing system cost.
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 detection of suspicious underground actions, such as tunnel digging, in a wide monitoring area at a lower cost by using an optical fiber to detect vibrations and identify patterns indicative of such activities.
Implementation Method 1
an optical fiber configured to detect a vibration in underground
Data Source
AI summary
An optical fiber sensing system according to the present disclosure includes an optical fiber (10A) configured to detect a vibration in underground, an acquisition unit (21) configured to acquire, from the optical fiber (10A), an optical signal on which the vibration detected by the optical fiber (10A) is superimposed, and an identifying unit (22) configured to identify a suspicious action in the underground based on a vibration pattern included in the optical signal acquired by the acquisition unit (21).