Experimental investigation of polarization rotation in twisted optical fibers

The twist induced polarization rotation in birefringent optical fibers is well understood and has been treated in the late seventies. We recently derived a formulation of the polarization rotation in twisted optical fibers using a tensorial coupled mode approach, that, other than existing theories, employs a fixed reference frame. This is interesting for fiber sensing applications, where the perturbing effects onto the fiber, such as strains induced by embedding the fiber into a host material, are conventionally given in a fixed laboratory reference frame. Hence, the derived theory can easily be integrated into existing formulations in the laboratory reference frame. In this work we demonstrate the experimental verification of the derived theory.We mechanically twist an optical fiber using an automated test stand and recording the change in polarization. The results are in close agreement with the theory.