Analysis of fiber-optic polarizing beam splitters consisting of fused-taper couplers

The characteristics of polarization splitting in fiber-optic couplers employing both nonbirefringent and birefringent fibers (PANDA fibers) are investigated. An analytical method that takes into account the cores, stress-applying parts, and stress birefringence in the coupling region is proposed. From comparison between the theory and experiments, the validity of the present analytical method is confirmed. It is shown that the length of the coupling region in birefringent-fiber polarizing beam splitters (BPBS) is several times shorter than that in nonbirefringent-fiber polarizing beam splitters (NPBS).