Verification of the direct measurement principle of linear velocity using Sagnac effect

With the development of technology, the demands for high-speed and high-precision processing for fabricating precision parts such as semiconductors and liquid crystals have been increasing. However, there is a problem that vibrations occur in ultra-precision machines. However, in order to improve machining accuracy, it is necessary to suppress the vibration of the machine tool. In a vibration control system, vibration is reduced by speed feedback. In the conventional method, speed control is performed by integrating acceleration. Therefore, there is a problem that the error is accumulated and the accuracy of measurement speed is reduced. Currently, linear velocity can't be measured directly without reference point, while angular velocity can be measured directly without reference. The angular velocity can be measured directly using the Sagnac effect, which is the basis of the optical gyro. Then, in this research, in order to realize the linear velocity measurement method which does not cause an error theoretically, we verified about the direct measurement principle of linear velocity using Sagnac effect.