Confinement losses in the birefringent holey fibers

We calculate and compare confinement losses in birefringent holey fibers of four different constructions. The birefringence in the analyzed structures is induced, respectively, by: two large holes adjacent to the fiber core; the elliptical shape of the core composed of double or triple defects in the hexagonal structure; one row of cladding holes with diameters lower than the other cladding holes. In the first step of loss analysis, we assume that all structures are composed of 5 rings of holes surrounding the fiber core. Finally, we optimize two fiber constructions in order to assure the minimum number of structural elements, while keeping the confinement losses below 1 dB/km.