高测速双频激光干涉仪的若干关键问题研究

新型的塞曼-双折射双频激光(DFL)器可连续输出频差3～40MHz的DFL，以这种激光器为光源的干涉仪允许的最高测速可达4m／s或更高。激光器输出的是两正交的线偏振光，针对这一特性设计装词了系统光路，观察到理想的频移现象。已有外差信号处理方法均不能移植用于处理中频差，改进大数对减法使之适合于处理中频差外差信号，得到50MHz以内无累积误差的计数结果。

Study on Some Key Problems in High Speed Dual Frequency Laser Interferometer

Novel Zeeman birefringence dual frequency laser(DFL) may produce dual frequency laser with tunable frequency difference from 3 to 40 MHz.The interferometer employing this laser as light resource will have top measurement speed of 4 m/s or even higher.The two lights are linear polarization lights with perpendicular polarizing directions.Systematic optic path is designed and constructed according to this character,and ideal frequency shifting is observed as the result.The past heterodyne signals processing methods may not be planted to use on mid-frequency difference.Big number minus method is improved and become suitable for processing mid-frequency heterodyne signals,and the system may count without cumulate error when input frequency is 50 MHz or below.