In this paper, an optical filter based on a two dimensional photonic crystalring resonator (PCRR) with triangular lattice is designed and presented. For thispurpose, the effects of positioning, arrangement and the number of the inner rods of thedual-curved PCRR on the performance characteristics of our optical filter such as thetransmission coefficient and the quality factor have been fully investigated. Calculationresults show that a transmission coefficient of 100% with a quality factor of 2400 at theoperating wavelength of nearly 1576 nm can be achieved. The proposed optical filtercomparatively performs better than the previously reported ones. In addition, thisstructure can be used for the design of optical multi-channel demultiplexer. To study thephotonic band gap of our structure, the plane wave expansion (PWE) method has beenused and the finite-difference time-domain (FDTD) method has also been employed toanalyze the optical behavior of the proposed device.

Ring resonators have always been referred to as a highly flexible structure for designing optical devices. In this study, we have designed and simulation a four channel optical demultiplexer using square photonic crystal ring resonator. The square lattice constant for this purpose structure is used. The purposed structure has an average crosstalk, transmission coefficient, quality factor and channel spacing of-14. 5 dB, 90%, 858 and 1. 6 nm, respectively. To obtain the photonic band gap of the structure, the plane wave expansion (PWE) method has been used and the finite-difference time-domain (FDTD) method has been also used to analyze the optical behavior of the structure. The good results obtained from designing and simulating optical demultiplexer structure such as narrower channel spacing indicate the high flexibility of this structure and ring resonator for being used in designing optical devices as well as their suitability for being used in wavelength division multiplexing (WDM) systems.

In this paper, an optical filter based on a two dimensional photonic crystal ring resonator (PCRR) with triangular lattice is designed and presented. For this purpose, the effects of positioning, arrangement and the number of the inner rods of the dual-curved PCRR on the performance characteristics of our optical filter such as the transmission coefficient and the quality factor have been fully investigated. Calculation results show that a transmission coefficient of 100% with a quality factor of 2400 at the operating wavelength of nearly 1576 nm can be achieved. The proposed optical filter comparatively performs better than the previously reported ones. In addition, this structure can be used for the design of optical multi-channel de multiplexer. To study the photonic band gap of our structure, the plane wave expansion (PWE) method has been used and the finite-difference time-domain (FDTD) method has also been employed to analyze the optical behavior of the proposed device.

ICT development has caused evolution in service delivery methods. With the increase in population density in urban areas, it is necessary to change and develop the infrastructures. Fiber optic network is a sustainable communication platform in the smart city and supports all broadband and narrowband services. In this paper, the role of fiber optics in the smart home (with broadband capability) and mobile network (5G) are considered as the two main parts of a smart city. A techno-economic model of communication infrastructure in the smart city (using multi-purpose fiber optic network with existing resources consideration) is stated by mixed integer linear programming (MILP) method. In this literature, whilst providing fundamental communication in the smart city, decreasing the vulnerability to threats and increasing the percentage of security and reliability, technical requirements are met and the Capital Expenditure (CAPEX) of network is reduced, as well.

Data transmission in optical systems and increased transmission distance capacity benefit by using optical amplification wavelength division multiplexing (WDM) technology. The combination of four waves (FWM) is a non-linear effect in the wavelength division multiplex (WDM), when more than two wavelengths of light in a fiber launch will occur. FWM amount depends on the channel, the channel spacing and dispersion fiber, but is independent of the bit rate. A simple equation for the spectral line width is shown. Dispersion causes distortion of the transmitted signals and needs to be compensated to achieve a long-haul system. The four-wave mixing effect have been studied as one of the factors influencing by using OPTISYSTEM Software. In this paper, a new approach for suppressing the four-wave mixing (FWM) crosstalk by using the pairing combinations of differently linear-polarized optical signals is investigated. The simulation is conducted using an eight-channel system. The proposed technique is to suppress the FWM interaction using different input powers. It has been evaluated for single-mode fiber (SMF). FWM can be strongly reduced, when the polarization technique is conducted for SMF. We also compare our new method with a conventional method to demonstrate the effect of FWM as well. The comparison was conducted at an input power range of 2 dBm. Decreasing the input power can decrease the FWM effects. In the absence of the polarization technique the FWM power was –64 dBm at an input power of 2 dBm. The FWM power decreased to less than -82 dBm at a 2 dBm input power. The system performance greatly has been improved.