Suppressing the nonreciprocal errors in a fiber optic rotation sensor

Abstract

Among several other types of rotation sensors, interferometric fiber optic gyro-scopes (IFOGs) shine out as they provide longer lifetime, quicker turn-on time, higher reliability, precision, and sensitivity. However, the fact that any environmental effects distorting the counter-propagating beams from travelling the identical path in a rotating loop induce phase differences apart from the Sagnac effect and cause error leaves them as an application which still needs to be improved. Therefore, we will start by paving the way with the studies we have conducted on the light source for improving its wavelength stability against temperature, and then we will steer our studies toward improving the quality of the fiber optic coil. Although IFOGs being a worldwide hot topic, most of the studies have been carried out by using quadrupole winding pattern, while only little is known when it comes to other winding patterns. Use of hexade-capole winding pattern paints a more promising picture and opens new doors in this research line. Being in the quest of finding a way to improve the performance of these sensors against such disturbing effects, we study and explore the thermal behaviours of the IFOGs built with fiber coils having different winding patterns. We demonstrate that the use of hexadecapole winding pattern overtowers the other winding patterns namely dipole, quadrupole, and octupole in the need of trimming as it presents lower absolute rate error; not only at a certain rate of temperature change but also under different rate of temperature changes. Moreover, we enrich our studies by further investigating the thermal behavior of these sensors, show the independency of Shupe effect in the direction of real rotation, and propose a novel method which eliminates the significance of the symmetry in fiber coil winding. We support our experimental findings with the simulations as well.