Theoretical research on tunable fiber devices in photonic crystal fiber

Tunable photonic handgap fibers (PBGFs) were theoretically investigated by using the vector plane-wave expansion methOd and the vector finite clement method. The tunable PBGFs arc fabricated by filling high index material in the air holes of index-guiding photonic crystal fibers. The wavelength dependence of leaky loss and group velocity dispersion (GVD) has been illustrated. We show the leaky loss in the tunable PBGFs can he strongly depended on the re&active index of filled material due to the photonic bandgap effect. The tunable attenuator which operates at 1550nm is designed based on this PBGFs.