Performance Investigation of 64 × 20 Gbps and 100 × 10 Gbps DWDM System using Hybrid Optical Amplification for different Modulation Formats

Abstract

For the need of higher capacity and speed optical fiber communication systems are being extensively used all over the world for telecommunication, video and data transmission purposes. Multimedia optical networks are the demands of today to carry out large information like real time video services. Presently, almost all the trunk lines of existing networks are using optical fiber. This is because the usable transmission bandwidth on an optical fiber is so enormous (as much as 50 THz) as a result of which, it is capable of allowing the transmission of many signals over long distances. However, attenuation is the major limitation imposed by the transmission medium for long-distance high-speed optical systems and networks. So with the growing transmission rates and demands in the field of optical communication, the electronic regeneration has become more and more expensive. The powerful optical amplifiers came into existence, which eliminated the costly conversions from optical to electrical signal and vice versa. The hybrid optical amplifier have attracted much attention as they are amplifies the broad bandwidth. The hybrid optical amplifier has wide gain spectrum ease of integration with other devices and low cost. This thesis is mainly concerned with the use of hybrid optical amplifiers in multichannel wavelength division multiplexing (WDM) optical communication system and network. In this chapter, WDM5systems at 645and5100 channels5have been5investigated5at 20 Gbps and 10 Gbps date rates respectively, with Raman-EDFA5amplifier and the5performance5has been investigated and compared5on the basis5of transmission5distance and5dispersion5with and without5nonlinearities for different modulation formats. Dual stage amplification is also5observed5for5Raman-EDFA. It is observed that5distributed RAMAN Amplifier provides5flat5gain spectra for narrow spaced channels and EDFA as second stage amplifier offers high gain. Further DWDM systems are compared base on modulation formats. Sixty four channels DWDM system is compared using NRZ, RZ and DPSK, while 100 channel DWDM system is investigated for NRZ and RZ in5terms of quality5factor, bit5error5rate and eye5height. It observed that RZ offer good quality factor (minimum 14 and maximum 24.5), less eye closure (maximum 2.69), tolerable bit error rate (3.875 × 108) at individual distance as compared to other formats. Further we investigated gain performance of5HOA (Raman5EDFA) after each stage (first stage Raman amplifier and second stage EDFA provides gain nearby 5 dB and 17 dB respectively).