Optical Gyroscope-on-a-Chip

Gyroscopes are devices that help vehicles, drones, and wearable and handheld electronic devices know their orientation in three-dimensional space. Originally, gyroscopes were sets of nested wheels, each spinning on a different axis. But in a cellphone, a microelectro-mechanical sensor (MEMS) measures changes in the forces acting on two identical masses that are oscillating and moving in opposite directions. These MEMS gyroscopes are limited in their sensitivity, so optical gyroscopes have been developed to perform the same function but with no moving parts and a greater degree of accuracy using a phenomenon called the Sagnac effect.