Abstract
Solid-core photonic bandgap fibers (SC-PBGFs) have gathered much attention because of its intriguing transmission band properties which can be understood by the theory for ARROW waveguides. In SC-PBGFs, it has been reported experimentally that the centripetal radiation as well as the centrifugal radiation occurs, when the fiber is bent at longer wavelength ranges in the PBG. This anomalous property was explained by considering the existence of the inner radiation caustic, which can not be seen in conventional optical fibers. However, the further analysis is required to understand the detailed properties of bent SC-PBGFs. In this paper, we investigate the bending loss properties for the SC-PBGFs through a full-vector modal solver based on the finite element method (FEM). In particular, we show that the cladding modes which induced by the bend cause the complete or incomplete leaky mode coupling with the core mode. Moreover, we show the structural and wavelength dependence of the bending losses for the SC-PBGFs.
