PCF structure with ‘Y’-shaped core, ‘T’-shaped core and a ‘D’-shaped PCF structure have been investigated. A full vector of Finite Difference Time Domain FDTD method has been used for analysis of results. Dispersion reported by ‘D’-shaped structure is found to be highly negative and structure with ‘Y’-shaped core reports anomalous behavior. Moreover, structure with ‘T’-shaped core reports zeros dispersion over communication wavelength. This structure also reports high birefringence and thus can be widely useful for optical communication and optical sensor. Moreover this reports single mode propagation at ultra low loss.