Abstract:
With the passage of time as the high data rate applications became common and necessary for the end-users and enterprises, bandwidth became a critical issue in Long-Haul and in the Metropolitan Area Networks. At that time optical fiber came to the rescue. It was considered that optical fiber has unlimited bandwidth and hence can handle the ever increasing demand of bandwidth. But due to the limitations posed by the electrical equipments and circuits there was a certain extent to which the bandwidth of fiber could be used. Hence the challenge was to effectively use the bandwidth of the fiber. “Wavelength Division Multiplexing (WDM)” was the technique used to achieve this goal. In WDM technique multiple wavelengths are transmitted over a single fiber separated by a certain distance using the concept of virtual channel. In WDM technology, two alternate technologies namely ‘Dense Wavelength Division Multiplexing (DWDM)’ and ‘Coarse Wavelength Division Multiplexing (CWDM)’ are used. In DWDM, a large number of wavelengths can be transmitted on single fiber. The systems of 32 and 64 wavelengths have already been developed and deployed. The DWDM is higher speed but expensive technology. In CWDM, 16 wavelengths channels are mostly used. In deployment of WDM systems, designing of WDM network is one of the key factor. The designing of WDM network includes selection of equipment, selection of architecture/topology, assigning of wavelength, routing of wavelengths, power budget and requirement of repeater/amplifier and location of repeater/amplifier. In this study, a design tool was developed to design SDH and DWDM/CWDM network. The design tool was given name OPTILINK. The OPTILINK can be used to design SDH and WDM network based on pre-defined data bases of equipment of specific vendor/vendors. OPTILINK supports several useful features such as design of network topology by drag/drop function; power budgeting, wavelength assignment and generation of Bill of Quantities (BOQ) for specific network. The design tool OPTILINK was used in two case studies. The designing of DWDM system was applied to designing of long haul communication link from Lahore to Peshawer. The long haul communication network was designed using OPTILINK. The designing of CWDM designing was applied to Islamabad Access Network. The metropolitan case study was also using OPTILINK.
