ABSTRACT
In this Entry, we describe the basic principles underpinning the physics of the ring laser gyroscope. After a short introduction to the Sagnac effect, we describe the operating principles of this rotation sensor, and discuss the main sources of performance limitation and the way they are usually circumvented. We also provide a brief comparison with the interferometric fiber-optic gyroscope, and discuss future prospects for optical gyroscopes in the short to medium term.
