Research Of Polarization Extinction Ratio Measurement System For Polarization Maintaining Fibers

Polarization maintaining fiber(PMFs) can maintain the polarization state of lights. PMFs are widly used in the fields of fiber optic gyro, optical fiber hydrophone, coherent optical communication and fiber sensing. Polarization extinction ratio(PER) is a important parameter to evaluate the ability of maintaining polarization state. Based on the computation model of PER and white light interferometry(WLI), the PERs measurement system of PMFs in 850nm was set up. The coupling intensity of single coupling point and PERs of PMFs were measured. Also, the beat length and alignment errors were measured. The spectrum distribution of light source and its influence on interferogram were analyzed in detail. Analysis and emulation were carried out for the disturbance signal of the mechanical scanning vibration. At last, the performance of PERs measurement system in 850nm was demonstrated.Major works of this dissertation1 Based on the computation model of PERs, the PER measurement system was set up.The programs of data acquisition and signal processing were written in Labview.2 It was measured that the coupling intensity of single coupling point and PERs of PMFs.3 Beat length and alignment errors of PMFs were analyzed theoretically and measured experimentally.4 It was analyzed and verified in experiment that the influence of scanning arm vibration and the spectrum variation on interferogram.5 Experimental results showed that the space resolution and the sensitivity of coupling points were 31mm and -73dB, respectively, the maxium length of PMF for measuring was 672m. The PERs measurement errors were better than±0.5dB compard to PERs meter .