Single-frequency Laser Interferometer Length Measuring System Anti-jamming Technology Segments

Systematic study on application of single frequency laser interference system in displacement measurement has been carried out. Due to the limitation of fringe counting, a new method is introduced to implement measurement by calculating the energy change of fringes on interference's plane. Based on the energy analysis of equal inclination fringes on focal plane with small inclined angle, mathematical model has been established and shows that energy change is a sinusoid of displacement with period ?/2. By tracing the direct current component of this energy, the zero drift problem is overcome and this enables the system stronger anti-jamming. A new subdivision method based on adaptive detecting of fringe phase is presented also.The experimental results are nearly in accordance with the theoretic analysis, which proves the correctness of the mathematical model and theoretic analysis of equal inclined interference fringes on focal plane. And simulating results indicate the feasibility of using energy tracing of direct current component to resolve optical "zero drift" problem and using adaptive detection of fringe phase to subdivide fringe which are promoted in this paper.