Measurements and modeling of modal birefringence and sensitivity to strain in a three-mode elliptical-core fiber

We measure phase and group modal birefringence and also polarimetric strain sensitivity in a three-mode elliptical-core fiber for all spatial modes. Our results show a very high difference in fiber sensitivity to strain versus mode order, which is negative for the E-11 mode and positive for E-31 mode. We also model all measured parameters using Optiwave BPM-Cad and Cosmos/M software packages. The measured values of phase and group modal birefringence agree well with those obtained from calculations for all spatial modes. We do not observe as good an agreement between experimental and calculated values of strain sensitivity, which is most probably caused by the lack of reliable material constants for SiO2 /GeO2 glasses. (C) 2004 Society of Photo-Optical Instrumentation Engineers.