قياس الانكسار الثنائي النمطي العالي تحت تاثير الشد عند لف الليف البصري احادي النمط

In this research the high model birefringence has been measured when a single- mode fiber is subjected to bending under tension effect where the fast axis of birefringence was coincided with radius of curvature. The source of the effect was an external lateral stress on optical fiber. the fiber was wound on cylindrical former for different radii and for different number of turns with different strains to obtain on high birefringence in fiber. Show the result has been obtained from research. When decrease radius of curvature, the birefringence result from bending increases, the relation ship between model birefringence induced bending under tension effect ( ) and the outer fiber radius -bend (k r) is linear for different radii and strains at the wave Length (=632.8nm), the experiment values result agree With the theory values birefringence show the linear dependence on (k)