Revisiting the Stress-Induced Birefringence in Polarization-Maintaining Fibers

Two conventional errors in the stress-induced birefringence (SIB) of polarization-maintaining fibers (PMFs) are revealed and corrected. The first issue refers to the fundamental expression and its calculation of the SIB, which depends on the selection of stress components. There were obvious inconsistencies in two pioneering reports, while both were widely applied in subsequent works. The second issue is the basic form of the Airy stress function (ASF) in the cross-section plane of the PMF, which dominates the complexity of the stress calculation for SIB. The ASFs in two early pioneering works were different, which led to two different expressions of SIB. Both expressions cannot be reproduced, and calculated results were just around 1/2 of the corresponding measurements. In this article, both issues have been fixed by revising the definition of SIB and proposing a new ASF form for PMFs. The developed theory is simple and does not have any mathematical contradiction in the calculation process, compare to reported works. Results of the revised SIB based on the developed theory achieve a good agreement with the practical experimental measurements.