Influence of nonlinear error on measuring accuracy for a dualfrequency heterodyne interferometer using a polarization maintaining fiber

摘要

Dual-frequency heterodyne interferometer has been widely applied in many fields. It is also an important part formeasuring position error in the system that laser simultaneously measure six degree of freedom geometric motion errorsof a linear guide. To segregate the heat source, simplify the optical path and obtain a convenient delivery, a polarizationmaintain fiber (PMF) is used in the system for linking the laser source and the measurement section. However, the nonlinearerror caused by PMF will reduce the measurement accuracy, and cannot be ignored in ultra-precision measurement. In thispaper, a measurement model for analyzing the nonlinear error caused by the axis misalignment between the laser sourceand PMF was established with the Jones Matrix. Experiments were performed for verifying and calculating. The resultsshow that the measuring error caused by nonlinear error is less than 2 nm with the axis misalignment being up to 10 degrees.