Terahertz circular fiber polarizers using suspended-core spiral fibers

摘要

A terahertz (THz) fiber circular polarizer based on suspended core fibers is proposed and analyzed. The THz mode guides within a subwavelength-scale core, which is suspended in a polymer tube. The dry air inner cladding not only suppresses the absorption loss of the device but also supports the leaky cladding modes. The circularly polarized core mode with the same handedness of the grating couples to the leaky cladding modes suffers from loss near resonant frequencies due to the spiral structure of the fiber. The principles and characteristics of the proposed circular polarizer are theoretically derived. Parameters that have influence on the performances are analyzed by numerical simulations. Simulation results show that the proposed THz fiber polarizer exhibits a broad single circular polarization bandwidth and a relatively low absorption loss. (C) 2017 Optical Society of America