Loss characteristics and field intensity distributions of fused polarization-maintaining fiber couplers are measured. From the results, it is shown that excess loss spectra have a sinusoidal response. Further, the loss peaks of the usual polarization-maintaining and absorption-reducing (PANDA) fiber couplers with index-depressed stress applying parts are larger than those of PANDA couplers with index-matched stress applying parts. It is also confirmed that low excess loss of <0.1 dB can be obtained for a large waist diameter of the fused region even in conventional PANDA fiber couplers.
© 1988 Optical Society of America
Original Manuscript: December 7, 1987
Published: December 1, 1988
Itaru Yokohama, Kazunori Chida, and Juichi Noda, "Low excess loss conditions of polarization-maintaining fiber couplers," Appl. Opt. 27, 4807-4813 (1988)