Real World DAS Sensing – Distance vs Fibre Attenuation

FFT Aura Ai-2 consistently leads the industry in reliable long distance detection due to innovative design and engineering.  For long distance buried fibre applications, where lower acoustic frequencies are of interest, the fibre attenuation and its effect on the signal-to-noise (SNR) ratio of the received backscattered signal becomes the dominant factor that determines the sensing distance.

While many DAS systems are based on Direct Detection techniques, the Aura Ai-2 design uses a coherent detection technique, based on optical heterodyning, which provides a superior receiver sensitivity and lower receiver noise than Direct Detection systems. By combining heterodyning with FFT’s proprietary Ultra Low Noise Balanced Detectors Aura Ai-2 is able to further improve its SNRs by at least a factor of 2 (3dB) and extends the reach of its systems for long range applications.  FFT Aura Ai-2  doubles this sensing distance advantage by having two sensing channels and industry leading event classification software.

Although claiming any definitive sensing distance capability requires a number of parameters to be defined (such as fibre attenuation, pulse repetition rate, background noise, and event of interest acoustic signal level) FFT’s Aura Ai-2 can operate effectively over greater distances due to superior optical design, and superior classification software.