Results obtained from field measurements using a novel distributed acoustic sensor based on geometric phase. The target application is Seismology where we attempt to characterise the Earth's subsurface.
Geometric phase measured per beat period1 in a ɸ-OTDR
based on coherent heterodyne detection2 is used to measure
strain3, instead of the traditionally measured dynamic phase.
The new setup is referred to as a ɸgOTDR. Results are
verified using a piezo-electric transducer inline a fiber-undertest.
A novel DAS setup based on geometric phase is used to measure surface waves of the Earth. They carry useful information about the structure and material of the Earth.
Introduction to Geometric Phase in time and space domain. Results showing successful detection of Geometric Phase using a distributed fiber optic sensor setup are presented.
Geometric phase showing sensitivity to changes in polarisation state (SOP) and intensity of backscattered light is measured using a novel φ-OTDR setup based on coherent heterodyne detection. Principle is demonstrated using a polarisation scrambler inline a fiber-under-test.
Earthquake monitoring using geometric phase. Planned foeld measurements at Horstwalde (BAM TTS) are discussed with Professor Serge Shapiro of Free University for a possible collaboration.