Measured phase and group birefringence in elliptical core fibers with systematically varied ellipticities.

This paper presents the first systematic phase and group birefringence measurements of elliptical core fibers covering an unprecedented ellipticity range from 0.1 to 0.9. Experimental results at 1550 nm are compared with simulations, and the birefringence ratio is shown to depend on both ellipticity and core area. Also the dispersion of the group birefringence is discussed.

Acoustic index of Ge-doped optical fibers.

A precise relation between the acoustic index and the amount of doped Ge in silica is established using both energy and wave dispersive spectroscopies on preform pieces and stimulated Brillouin scattering in optical fibers. It is shown that the relation is in very good agreement with a simple model involving only GeO(2) and SiO(2) bulk parameters. The change in the acoustic index is found to be 3.97x10(-3)/wt. %GeO(2) at 1550 nm.