Sagnac interferometry for the determination of rotations in geodesy and seismology

Abstract

Rotation sensors exploiting the Sagnac effect have many advantages, which give rise to a broad range of applications in which such sensors are irreplaceable. By vastly increasing the size, and consequently scale factor and sensitivity of ring lasers this group has achieved relative Earth rotation measurement resolution of 2 × 10−8. Today the real-time measurement delivered by large ring lasers provides data complementary to VLBI observations [7]. The application of optical sensors in seismology is an entirely new field, which is constantly evolving with the increased demand for quality data and analysis. Both ring lasers and fiber optic gyros can be employed for various seismological measurements, providing rotational information, which cannot be obtained via traditional seismometers. This paper presents an overview of current large ring laser development status, as well as insight into new research areas where both ring lasers and fiber optic gyros can help to obtain information of great value.