The purpose of this paper is to design a hexagonal microstructure photonic crystal fiber (PCF) which gives ultra-high birefringence and very low confinement loss for sensing application. To characterize the modal properties of the proposed photonic crystal fiber, finite element method is used. We found ultra-high birefringence of 3.34×10-2 at operating wavelength 1550nm by using simulation software comsol multiphysics. Our proposed PCF gives large value of nonlinear coefficient of 63.51 W-1km-1, large value of negative dispersion coefficient of -566.6 ps/ (nm.km), and also ultra-low confinement loss which is in the order of 10-7.
The orbital angular momentum (OAM) of light is used for increasing the optical communication capacity in the mode division multiplexing (MDM) technique. A novel and simple structure of ring-core photonic crystal fiber (RC-PCF) is proposed in this paper. The ring core is doped by the Schott sulfur difluoride material and the cladding region is composed of fused silica with one layer of well-patterned air-holes. The guiding of Terahertz (THz) OAM beams with 58 OAM modes over 0.70 THz (0.20 THz–0.90 THz) frequency is supported by this proposed RC-PCF. The OAM modes are well-separated for their large refractive index difference above 10−4. The dispersion profile of each mode is varied in the range of 0.23–7.77 ps/THz/cm. The ultra-low confinement loss around 10−9 dB/cm and better mode purity up to 0.932 is achieved by this RC-PCF. For these good properties, the proposed fiber is a promising candidate to be applied in the THz OAM transmission systems with high feasibility and high capacity.
Design of simple circular photonic crystal fiber having high negative dispersion and ultra-low confinement loss