Optical Fiber Interferometer Displacement Measurement With Large Range And High Resolution Based On Wavelength Division Multiplexing

Nano-measurerment technology is a branch subject of the Nanotechnology. With the rapid development of science, nanotechnology has extended to a wider filed involving machinery, materials, electronical,biology,chemistry and so on,it demands more and more nano-measurerment.As the demanding of industrial technology,The next advancement for nano-measurerment is higher resolution and wider measurement range.It is proposed a fiber interferometric measurement system which is based on WDM technology in this paper. The system established on the basis of fiber Michelson interferometer, employing fiber couplers, fiber Brag gratings(FBGs) and other optical devices. At the same time, it introduced the composite wave using WMD technology.On the one hand,this system has expanded the measurement range by demodulating the interferometric signals of the composite wave.On the other hand,it improved the resolution of the measurement by demodulating the interferometric signals of the single wave. There was an electronic feedback loop to drive a piezoelectric (PZT) actuator to tune the optical path of the reference beam in order to keep the interferometer in quadrature state. By this way, the low frequency drifts in the phase of the interferometric signals which were resulted from environmental disturbances were compensated for. It successfully stabilized the system.Followed is the main task of this paper.(1)Built the optical measurement system and obtained the expected the interferometric signals to prove the feasibility of this measurement system. (2)Employed an electronic feedback loop to stabilize the system, and increased the accuracy.(3) The signals were collected and processed by LabVIEW program in a personal computer and made it more suitable for online measurement.