Study On A Laser Micro Displacement Measuring System Based On The Principle Of Spectral Interference Using Optic Fiber

With the development of micro-nano manufacture technology in the fields of micro-machine,micro-fabrication,micro-electronics,bio-medicine and so on,high requirements for micro-nano technology measurement have been proposed.The micro displacement measurement technology based on laser and optical fiber has aroused people's wide attention.A laser micro displacement measurement system using only one fiber has been developed after reviewing the literatures about fiber interference measuring techniques.The system is made up of a laser diode,an optical circulator,a collimator,a photodetector and some signal processing circuits.The output end of the collimator is used as a reference mirror.The measuring light and the reference light will interfere each other after passing through the same single mode optical fiber.The optical path difference will happen when the measuring mirror has a displacement.The interfere patterns can be detected by the photodetector and the measured displacement can be obtained via signal processing.The collimator is made up from fiber and have the advantages of small size and no thermal resource.Portable measurement is suitable for the system.An experimental setup has been finished based on a long stroke table,a PI sano-motion table and a SIOS interferometer.The qualitative and quantitative measurements were achieved.The experimental results show that the measurement range of this system is 4.4 mm with a deviation of 300 nm.