Linking Distributed and Integrated Fiber?Optic Sensing

Distributed Acoustic Sensing (DAS) has become a popular method of observing seismic wavefields: backscattered pulses light reveal strains or strain rates at any location along fiber-optic cable. In contrast, few newer systems transmit through cable and collect integrated phase delays over the entire cable, such as Microwave Frequency Fiber Interferometer (MFFI). These can be deployed significantly longer distances, may used in conjunction with live telecommunications, cheaper. However, they provide only single time series representing length fiber. This work discusses theoretically how distributed system quantitatively compared, we note that sensitivity depends strongly on points curvature. Importantly, this presents first results quantitative, head-to-head comparison DAS MFFI using pre-existing telecommunications fibers Athens, Greece.