Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer.This technique usually requires that only one polarization mode is excited.However,in practical measurement,the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF,so the influence of the polarization extinction ratio should be considered.Based on the polarization coupling theory,the influence of the incident polarization extinction on the measurement result is evaluated and analyzed,and a method for distributed polariza-tion coupling detection is developed when both two orthogonal eigenmodes are excited.
An electronic speckle shearing phase-shifting pattern interferometer (ESSPPI) based on Michelson interferometer was based in this paper. A rotatable mirror driven by a step motor in one of its reflective arm is used to generate an adjustable shearing and the mirror driven by piezoelectric transducer (PZT) in the other reflective arm was used to realize phase- shifting. In the experiments, the deformation of an aluminum plate with the same extern-force on different positions and different forces on the same position is measured. Meanwhile, the phase distribution and phase-unwrap image of the aluminum plate with the extern-force on its center position is obtained by the four-step phase-shifting method.
XU Tian-hua, JING Chao, JING Wen-cai, ZHANG Hong-xia, JIA Da-gong, and ZHANG Yi-mo College of Precision Instrument & Optoelectronics Engineering, National Education ministry Key Laboratory of Opto- electronics Information and Technical Science, Tianjin University, Tianjin 300072, China
