The measurement of vibration, strain, and temperature in a fiber optic cable (new or existing) relies on the interaction between a laser light and the glass in an optical fiber.
When light travels through a transparent media, the main pulse travels forward, however a small fraction is backscattered through interaction with the glass particles. This changes at every point along the cable in accordance with the local environment.
Different backscatter processes can be used to extract relevant information.
That backscatter signal can be exploited by different technologies to understand the external environment– vibration, strain, temperature, etc.
The end data can be used to understand the environment at every point along the fiber and act on the information.
The DAS interrogator is connected to one end of the fiber optic cable and a laser pulse is sent it through the fiber. When travelling into the cable, a small part of the light pulse is sent back to DAS interrogator due to the reflections and scattering produced by random imperfections existing inside the core fiber.
When the position of these heterogeneities change, a phase difference between the laser pulse and the backscattered pulse can be measured and cable elongations are calculated.
Thus, this technology converts the optical fiber in an array of thousands of sensors by sending laser pulses through the cable and recording their reflections and scattering in the DAS interrogator.
Overall, DFOST® offers a flexible and versatile solution for monitoring physical parameters along large structures and in harsh environments and provides a high-resolution, long-range, and cost-effective alternative to traditional point sensors.
Our advantages include long-range & real-time sensing, high-resolution, low power consumption, immunity to electromagnetic interference, multiplexing, low maintenance, and cost-effective.
DFOST® Distributed Acoustic Sensing (DAS) is used for monitoring various types of infrastructures because it provides a real-time, cost-effective, and non-intrusive method of monitoring.
Our main applications & objectives are pipeline monitoring, borehole & well monitoring, power cable monitoring, industrial equipment & facilities monitoring, transport monitoring, perimeter intrusion & border protection monitoring, geotechnics monitoring, and structural health monitoring.
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