Fiber optic gyroscopes measure the phase difference between two directions of light, and the gyroscope locks the phase difference between the two directions through a Y waveguide device.In order to improve the phase difference/RPM coefficient, a larger enveloping area is required, i.e. a longer optical fiber is required
The laser gyro measures the frequency difference between the two directions of light, and the smaller the surrounding area can have a more obvious frequency difference.The speed of laser gyroscope is indicated by fringe counting, which does not need closed-loop control
Fiber optic gyroscope (FOG) can also be measured in a similar way to laser gyroscope in principle, but the various optical effects that occur in practice make this method difficult to achieve.