“…Furthermore, research has shown that achieving high birefringence, high nonlinearity and negative dispersion can be useful for polarization control in fiber optic sensors, telecommunication applications and broadband dispersion compensation in high-bit-rate transmission systems 22 . A lot of work has been reported recently to achieve high birefringence, high nonlinearity and dispersion management through the use of elliptical holes around the core 23,24 , using different shapes of air holes other than circular in or around the core [25][26][27] , defective core 21 , doping the core with gas or liquid and hybrid cladding 28,29 , double cladding 22 , dual core photonic bandgap 30 , triangular lattice 31 and other shapes of air hole rings apart from the widely used hexagonal lattice [32][33][34][35] . Rhombic and elliptical hole PCFs have been presented 26 to achieve birefringence (B) of 8 × 10 -3 and Confinement loss(CL) of 5 × 10 -4 dB/m at 1.55 µm.…”