The optical communications have been the backbone of the most dramatic developments in telecommunications systems in the past two decades, so that the current world of communications is unthinkable without the infrastructure of ber optic networks. Also, the speed and bandwidth of optical devices have expanded the development of optical telecommunication systems, so the design, simulation and fabrication of optical devices have become more and more respected by researchers in this eld. In this paper, a design for optical narrow Band Pass Filter (BPF) using two-dimensional (2D) photonic crystals (PCs) is presented that are suitable for applications in optical ber communications (third window) in Wavelength-Division Multiplexing (WDM) systems. BPF was simulated by a two-dimensional timing method (FDTD) Finite-difference time-domain (FDTD). Also, the plane-wave expansion (PWE) method was used to evaluate the bands and calculate the Photonic Band Gap. Simulation results show this desired structure, acts as a very sharp optical BPF in the central wavelength of 1550 nm (In order to minimize attenuation). Normal voltage transmission e ciency, full width at half maximum (FWHM), and Focal Plane Module (FPM) for proposed BPF were 94.8%, 2583 and 0.6 nm, respectively.