Certain investigations on Performance of long haul optical Dwdm transmission systems and Networks

Abstract

Optical fiber communication is widely used in many telecommunication industries where the information is transmitted in the form of light signal through an optical waveguide. Optical fibers have several advantages over electrical transmission. The data can be transmitted at a faster rate over long distances. The optical signals are immune to electromagnetic interference and has high electrical resistance. The size of optical fiber is much smaller and can even be used in ducts. It is also of light weight which makes it possible to use in ships and aircraft. In optical communications, Wavelength Division Multiplexing (WDM) is a technology where multiple optical signals of different wavelengths are combined onto a single optical fiber in order to increase the information carrying capacity of the optical fiber. Wavelength division multiplexing systems can be divided based on the spacing between the channels as Dense Wavelength Division Multiplexing (DWDM) and Coarse Wavelength Division Multiplexing (CWDM). Dense Wavelength Division Multiplexing (DWDM) combines multiple signals that are to be transmitted over fiber with less spacing between the channels. The hybrid Time Division Multiplexing (TDM) and Dense Wavelength Division Multiplexing (DWDM) system further improves the capacity of the system. It serves the increasing consumer demands for bandwidth with high reliability. A modulation format that is more tolerant to impairments is needed in an optical system. Using appropriate modulation format, the capacity of the system can further be improved and better spectral efficiency is achieved. The modulation format which has narrow spectral width is ideal for long haul, high speed and WDM transmission links. newline