The fiber-optic gyroscope: actually better than the ring-laser gyroscope?

The fiber-optic gyroscope started to be investigated 35 years ago, opening the way for a fully solid-state rotation sensor. It was firstly seen as limited to medium-grade applications, but today, it reaches ultimate theoretical performance and surpasses its well-established competitor, the ring laser gyroscope, in terms of bias noise and long-term stability.