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Hybrid OCDMA/WDM system using Spectral Direct Detection technique for Gigabit Passive Optical Network application

2017-01-01 , S.M. Monirul Islam , Nasim Ahmed , Sharafat Ali , Rahman M. , Syed Alwee Aljunid Syed Junid , R Badlishah Ahmad

This study a hybrid Optical Code Division Multiple Access (OCDMA) over Wavelength Division Multiplexing (WDM) network is proposed to supporting large numbers of subscribers for Gigabit Passive Optical Network (GPON). Gigabit Passive Optical Network (GPON) is a developing innovation for satisfying high transfer speed interest of clients with long separation scope. In this study, the Modified Double Weight (MDW) code is used as signature address to designing the system regarding this code can accommodate huge number of simultaneously active users. The simulation model of GPON systems is derived by Spectral Direct Detection (SDD) technique which has been developed for the analysis of feasibility and implementation issues of the application. The aim was to analyse the impact of the most important parameters of the components that are needed for new network elements. On the basis of the results achieved (e.g., =10-10) the optimal of the GPON system for 20 km fibre length. Hence, this system can be considered as a promising solution for gigabit passive optical network application.

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Low loss dispersion flattened hybrid porous core photonic crystal fiber for terahertz wave guiding

2017-05-01 , Sharafat Ali , Nasim Ahmed , Monirul Islam , Syed Alwee Aljunid Syed Junid , R Badlishah Ahmad

This manuscript represents a hybrid type porous core photonic crystal fiber for THz propagation. The proposed fiber has showed excellent waveguide properties regarding Effective Material Loss (EML) and near zero flat dispersion. The reported EML is considerably low with a long range of near zero flat dispersion characteristics. The proposed hybrid design consists of a circular core with central air hole and octagonal cladding having only circular air holes. Different waveguide properties of the fiber have been reported for different core diameter and porosity of the core. The confinement loss, effective area, power fraction of the proposed fiber also has been reported. The waveguide has exhibited a low EML of 0.027 cm−1at 1 THz frequency for 60% porosity and 400 μm core diameter with 1.0–3.0 THz near zero flat dispersion of ±0.42 ps/THz/cm. The proposed porous fiber is efficient for broadband transmission of THz radiation.