The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement.
The characteristics of the best known defect centers E' in silica optical fiber material irradiated with ray were investigated by ESR at room temperature.A mechanism model of production of the E' center defect was established.The production of E' center includes two processes creation and activation.The strained bonds(or oxygen replacement) in silica networks lead to the creation of new defects whose concentration increases linearly with the dose.The pre-existing defects produce the activation,which tends to saturation.According to this model,the relation of E' center concentration changing with irradiation dose was obtained theoretically.The results are in good agreement with the experimental results.
LUO WenyunXIAO ZhongyinWEN JianxiangYIN JianchongWU WenkaiCHEN ZhenyiWANG ZihuaWANG Tingyun
