Study on Characteristics of Tilted Fiber Grating

Abstract

Compared with the fiber Bragg grating (FBG), the tilted fiber grating (TFBG) has the coupling between core mode and cladding mode or the radiation mode because of the tilt angle, which improves the sensitivity to the external environment. B ased on the coupled mode theory and the simulation software OptiGrating , the spectral characterist ics of the TFBG with different tilt angles were studied. When the tilt angle is small, the resonant peaks on the transmission spectrum move in the long wave direction with the increase of the tilt angle. What ’ s more, the transmission loss and transmission width decrease and the group delay decreases. W hen the tilt angle is large enough, the TFBG has strong bifurcation effect, the Bragg resonant peak disappears while the cladding mode resonant peak appears in pairs, and the high order cladding mode birefringence effect is stronger than the low order clad ding mode. In the end of the paper, different angles of sensing applications were analyzed.