Birefringence Measurement by Expandable Polarization Interference Method

In this article, an improved polarization interference method is proposed for fiber birefringence measurement. This method uses two different lengths of a birefringence fiber with their birefringent axes orthogonally coupled to compensate the phase difference and achieve the required pitch in interferogram for determining birefringence accurately. Experiments and analysis demonstrate that the method could offer improved accuracy and expanded range in birefringence measurement with relatively low spectral resolution systems.