dAS
The DAS (Distributed Acoustic Sensing) system is based on the principle of coherent Rayleigh scattering. When external sound waves (vibrations) act on the optical fiber, they alter its spatial structure, causing localized vibrations within the fiber and resulting in phase changes in the Rayleigh backscattered light signal.
When light of a specific intensity is injected into the fiber, the Rayleigh backscattered echoes are received. These echoes carry information about the vibrations occurring along the fiber. By demodulating the phase variations of the optical signal, the system can not only determine the exact location of the vibration event but also reconstruct the vibration (acoustic) information in the affected area.
Product Features
Key Performance Specifications
Vibration frequency monitoring range (≤0.1 Hz to ≥50 kHz)
Signal Acquisition & Real-Time Processing
Continuous real-time full-line phase demodulation
Local storage
Real-time protocol-based phase export
AI algorithm integration support
Advanced Algorithm & Signal Optimization
Dual-polarization diversity reception (eliminate polarization fading)
Phase unwrapping & filtering algorithm (eliminate phase jump & drift)
Coherent fading suppression algorithm
Information Form
| Parameters | BLAS—R25 |
|---|---|
| Fiber Type | Single—mode |
| Maximum Sensing Distance | 25 km |
| Spatial Resolution (Gauge Length) | 0.8 m, 1.6 m, 3.2 m, 4 m, 6.4 m, 8 m, 16 m |
| Number of Channels | 4 channels |
| Full-Line Phase Demodulation | Supports synchronous full-line phase demodulation |
| Phase Data Storage | Supports real-time local storage of full-line phase data |
| Phase Data Export | Supports real-time export of full-line phase data |
| Monitoring & Playback | Supports real-time continuous monitoring and playback |
| Output Options | Demodulated phase |
| Output Data Format | Optional: SEGY, HDF5, DAT |
| Vibration Frequency Monitoring Range | 0.1 Hz – >50 kHz |
| Polarization Fading Processing | Supports polarization fading elimination |
| Noise Floor | ≤ 30 pε/√Hz (Gauge length: 8 m, Frequency: 100 Hz) |
| User Interface Protocols | Socket (TCP), Serial Port, UDP |
| Main Unit Chassis | 3U rack-mount |
| Power Supply | AC 220V |
| Power Consumption | < 45 W |
| Weight | 10 kg |
| Operating Temperature | 0°C – 40°C |
| Operating Humidity | 0–95% (non-condensing) |
