Integrated photonics is the future development trend for communication and sensing system. Furthermore, the MEMS gyroscopes need special packing and complex readout electronic circuit, which increase the costs. Since their sensing elements include moving parts, an acceleration or vibration will be mistakenly detected as the angular speed 8. However, the MEMS gyroscopes suffer from the unreliability caused by the unstable mechanical structure.
Micro electro-mechanical system (MEMS) gyroscopes 7 have gained a lot of attention for the small size. Because of ever increasing demands for gyroscope in the consumer electronics market, the major concern is on miniaturization and low cost. However, RLGs and IFOGs are expensive bulk sensors, resulting in the disadvantages of weight, footprint and power consumption.
Majority of high-precision gyroscopes are based on the optical Sagnac effect 1 such as ring laser gyroscopes (RLGs) 2, 3 and interferometric fiber optic gyroscopes (IFOGs) 4, 5, 6, with sensitivities in the range of μdeg/s to thousand μdeg/s. Gyroscope is a kind of angular velocity sensor, which is widely used on airplanes, ships, cars and even mobile phones nowadays.
