We have manufactured and characterized a birefringent holey fiber of a new construction. The birefringence in this fiber is induced by the highly elliptical shape of the core, which consists of a triple defect in a hexagonal structure. Using a hybrid edge-nodal finite-element method, we calculated the spectral dependence of phase and group modal birefringence for spatial modes E_11 and E_21 in idealized and in real fiber, whose geometry we determined by using a scanning-electron microscope. Results of our calculations show that technological imperfections significantly affect the fiber's birefringence. Normalized cutoff wavelengths for higher-order modes relative to the filling factor were also determined for the idealized structure. We observed a significant disagreement between theoretical and experimental values of cutoff wavelengths, which was attributed to high confinement losses near the cutoff condition. We also measured the spectral dependence of the phase and the group modal birefringence for spatial modes E_11 and E_21. The measured parameters showed good agreement with the results of modeling.
© 2005 Optical Society of America
Marcin Szpulak, Gabriela Statkiewicz, Jacek Olszewski, Tadeusz Martynkien, Waclaw Urbanczyk, Jan Wójcik, Mariusz Makara, Jacek Klimek, Tomasz Nasilowski, Francis Berghmans, and Hugo Thienpont, "Experimental and theoretical investigations of birefringent holey fibers with a triple defect," Appl. Opt. 44, 2652-2658 (2005)