Distributed Sensing
Advanced fiber optic technologies offering continuous monitoring along entire structures
Distributed Fiber Optic Sensing (DFOS) represents a revolutionary approach to structural health monitoring, transforming a standard optical fiber into thousands of virtual sensors. Unlike traditional point sensors that measure at discrete locations, DFOS systems provide continuous, spatially-distributed measurements along the entire fiber length—from meters to tens of kilometers. This technology enables unprecedented insight into structural behavior, detecting localized anomalies that might be missed by conventional monitoring systems while simultaneously providing global structural response data.
Technology Advantages
- Thousands of measurement points with a single cable
- Coverage of large structures (up to 70km)
- Immune to electromagnetic interference
- No electrical components at sensing points
- Both strain and temperature measurement
- High spatial resolution (down to 1cm)
Why Choose DFOS Technology?
Distributed fiber optic sensing offers unique advantages for large-scale infrastructure monitoring:
- Achieve up to 10,000+ measurement points with a single fiber cable
- Detect localized damage or anomalies anywhere along the structure
- Monitor inaccessible areas like tunnel linings and buried pipelines
- Immune to electromagnetic interference and lightning strikes
- Intrinsically safe for hazardous environments (no electrical signals)
- Simultaneous strain and temperature measurements
Applications
Long-Span Bridges
Monitor entire bridge decks, cables, and girders with continuous strain profiles revealing load distribution and structural response.
Tunnels & Underground Structures
Install fiber optics in tunnel linings to detect ground movement, convergence, and potential structural issues along the entire length.
Pipeline Monitoring
Continuous leak detection, temperature monitoring, and third-party intrusion detection along oil, gas, and water pipelines.
Dams & Embankments
Monitor deformation, seepage, and temperature gradients across large dam structures and earth embankments.
Railway Infrastructure
Track rail deformation, ballast settlement, and structural integrity of railway bridges and tunnels.
Our Distributed Sensing Technology
QUAD-S Monitoring deploys cutting-edge DFOS systems utilizing multiple interrogation techniques to meet diverse monitoring requirements. We provide complete turnkey solutions from fiber selection and installation to data interpretation and reporting.
BOTDA Systems
Brillouin Optical Time Domain Analysis for long-range (up to 50 km) strain and temperature monitoring with meter-scale spatial resolution.
OFDR Systems
Optical Frequency Domain Reflectometry providing millimeter spatial resolution for detailed strain mapping up to 70 meters.
DAS Systems
Distributed Acoustic Sensing for vibration and dynamic event detection along fiber cables up to 100 km.
Sensing Cables
Application-specific fiber optic cables optimized for strain coupling, temperature sensing, and long-term durability.
DFOS Technologies Comparison
| Technology | Range | Spatial Resolution | Measurement Type | Best Application |
|---|---|---|---|---|
| BOTDA | Up to 50 km | 0.5 - 1 m | Strain & Temperature | Long bridges, pipelines, tunnels |
| OFDR | Up to 70 m | 1 - 5 mm | Strain & Temperature | Detailed crack detection, joints |
| DAS | Up to 100 km | 5 - 10 m | Vibration & Acoustic | Intrusion detection, traffic monitoring |
Frequently Asked Questions
How does DFOS differ from traditional point sensors?
Traditional sensors measure at specific points (e.g., every 10 meters), while DFOS provides continuous measurements along the entire fiber—essentially thousands of sensors in one cable. This means you will not miss localized damage between sensor points.
Can DFOS measure both strain and temperature simultaneously?
Yes, BOTDA and OFDR systems measure both parameters simultaneously. Temperature compensation is crucial for accurate strain measurements, and DFOS provides this inherently.
What is the typical lifespan of a DFOS installation?
When properly installed and protected, fiber optic cables can last 20-50 years. The fibers themselves do not degrade, and interrogators can be replaced or upgraded without changing the installed cables.
Is DFOS suitable for dynamic measurements?
Standard BOTDA/OFDR systems are best for quasi-static measurements. For high-frequency dynamic measurements (vibrations, traffic), we recommend DAS (Distributed Acoustic Sensing) systems that can sample at kHz rates.
