Investigation of high birefringence and chromatic dispersion management in photonic crystal fibre with square air holes

In this article, a solid core photonic crystal fibre (PCF) with square air holes is proposed and numerically analysed. The confinement loss, the chromatic dispersion and the birefringence are calculated for both triangular and square lattices by using a full vector finite difference time domain (FV-FDTD) method and the perfectly matched layers (PML) boundary conditions. Two main applications are then investigated: high birefringence and chromatic dispersion management. For the first one, simulation results indicate that high birefringence of 2.5 × 10−3 is achieved at the wavelength 1.55 μm with a very low bending loss of 1.8 × 10−3 dB/km for bent radius of 2 mm. In the second application, ultra-flattened chromatic dispersion over a wide band of wavelengths from 1 μm to 1.8 μm can be obtained with both positive and negative regimes.