Fiber Optical Coherence Domain Polarimetry for PM Fiber Measurements

Optical coherence domain polarimetry (OCDP) utilizes incoherent light and is based on Michelson interferometer. This paper presents a polarization maintaining (PM) Michelson fiber interferometer utilizing a single PM fiber loop mirror (Sagnac Loop) that replaces the conventional free space mirrors for OCDP systems. This implementation is environmentally robust and alleviates much of the mechanical complications necessary to reduce temperature and vibrations effects. A piezoelectric transducer (PZT) is inserted in one of the arms of the interferometer and driven near its resonance. This enables a detailed measurement of polarization coupling around any point in the device under test. An analytical model is given, based on Pauli matrices algebra, that includes the side effects due to component imperfections. It is shown that the polarization coupling in the PZT has the largest side effect on the OCDP output. Experimental investigations verify the accuracy of the theoretical model. Measurements are done on two PM PANDA fibers of lengths 20 and 150 m, respectively. In addition, the new system successfully measures distributed polarization mode coupling, group birefringence, and group birefringence dispersion for the fiber under test.