Ultra-flattened dispersion hexagonal photonic crystal fibre with low confinement loss and large effective area

In this study, a new photonic crystal fibre (PCF) structure is proposed which is suitable for optical telecommunications. This PCF has some features including low- and ultra-flattened dispersion and low confinement loss as well as a large effective area in a wide range of wavelengths. To analyse this PCF, finite-difference time-domain (FDTD) method with the perfectly matched layers boundary conditions has been used. For the proposed PCF, dispersion has small variations about 0.8 ps/(nm km) in the wavelength range from 1.1 to 1.7 m and dispersion value is less than 2.5 ps/(nm km) in applicable wavelengths. The confinement loss is obtained less than 10^-6 dB/km in this range, whereas the effective area is around 61.2 m² at 1.55 m wavelength. The results show that the confinement loss of the designed hexagonal PCF is small, although the effective area is large. The optimal structural parameters are designed to achieve minimum confinement loss, dispersion and dispersion variation which can be properly utilised in broadband optical transmission applications.