According to the ITU-T G694.2 standard in 8-channel CWDM systems, optical channels are mixed together in the wavelengths range of 1311 nm to 1451 nm (with the aim of minimum dispersion) and 1471 nm to 1611 nm (with the aim of minimum attenuation) with a channel spacing of 20 nm. Currently, CWDM systems in comparison with DWDM systems are more attractive because they are low cost. In optical telecommunication network, the Coarse Wavelength-Division Multiplexing (CWDM) systems and Dense Wavelength-Division Multiplexing (DWDM) systems are the two patterns for WDM systems. These systems consist of a multiplexer at the transmitter to combine the optical signals into a single signal and a multiplexer at the receiver to separate the combined signals. Hence, in optical telecommunication networks one of the ways to increase the capacity of data transmission is by using WDM systems. WDM systems are used in the transmission of information types such as voice, internet, video, and etc. In optical communication systems, optical filters are considered vital elements for wavelength division multiplexing (WDM) applications.
#Ful lattice crystal filter design Pc
In PC structures, the PBG is a range of frequencies which electromagnetic wave can not be propagated into the structure. PCs are good choices for designing optical filters and other similar elements because of their photonic band gap (PBG). 2D PCs compared with 1D and 3D PCs have attracted more attentions because they have a complete PBG and also they can be fabricated much easily using integrated circuit technology. These nanostructures are divided into three principle groups one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) structures.
PCs are nanostructures that their dielectric materials refractive indices change periodically. In recent years, PCs have attracted more attentions, due to having applications in optical electronics, telecommunications and optical information processing.
Introduction Currently some of important purposes of researchers in the field of optical electronics and photonics, are design of photonic crystal (PCs) devices. High transmission efficiencies, acceptable quality factors and low FWHM are important characteristics of proposed filter.ġ.
#Ful lattice crystal filter design full
The simulation results confirm the normalized output transmission efficiencies, quality factors (Q) and Full Width at Half Maximum (FWHM) for desired BPF are equal to about 99%, 497 and 3 nm (for 1491 nm) and nearly 100%, 310.2 and 5 nm (for 1551 nm), respectively. The normalized transmission spectra simulations and the Photonic Band Gap (PBG) calculations for the desired filter are done using two-dimensional finite-difference time-domain (2D-FDTD) and Plane Wave Expansion (PWE) methods, respectively. The desired BPF is composed of a 20×19 square lattice of dielectric rods using semiconductor InAs rods. It is centred at wavelengths of 1491 nm and 1551 nm with the aim of minimum attenuation. In this paper, a simple and non-complex structure for an optical double Bandpass Filter (BPF) based on two-dimensional (2D) Photonic Crystal Ring Resonators (PCRRs) is suggested for ITU-T G.694.2 8-channel Coarse Wavelength Division Multiplexing (CWDM) optical systems.