EVALUATING THE PERFORMANCE OF HYBRID AMPLIFIERS FOR HYBRID WDM/TDM PASSIVE OPTICAL NETWORKS (PON)

Abstract

Recent advancements in internet services have brought attention to access networks to have their bandwidth increased as they represent the last hurdle to the customer. Emphasis is put on high bit-rate transmission, network reliability and survivability as ways to reduce operational costs and enhance network coverage, scalability to curb capital costs. Researchers are seeking at improving the optical access network concepts known as hybrid wavelength-division-multiplexed and time-division multiple access passive optical networks. The networks are designed to be beneficial for operators due to low capital and operating expenditures. The passive optical network comprises of a centralized optical line terminal (OLT), situated in the central office and a number of optical network units (ONUs) are positioned some distance away from the OLT at the user end. Due to the need for longer and unrepeated transmission distances and higher capacity transmission, Hybrid WDM/TDM Passive optical transport networks are primed to give the capacity needed to meet the exponentially exploding telecommunications traffic in a cost-reduced way and used in conjunction with appropriate hybrid amplifiers great results have been realised. In this thesis, a hybrid WDM/TDM PON with a split ratio of 128 ONUs in the absence of amplification is investigated and a maximum transmission distance of 28km realised. Similarly, a Hybrid WDM/TDM PON with various Hybrid Optical Amplifiers for mid-range amplification is simulated and the performance is compared on the basis of BER, Quality factor (Q), eye opening and the maximum reach. The hybrid amplifiers RA –EDFA and EDFA-RA, RA-SOA and SOA-RA and SOA-EDFA and EDFA-SOA are simulated and compared to each other. It is seen that the hybrid amplifier RA-EDFA provides the highest output quality factor of 6.25257 and least bit error rate of 2.00309 x 10-10 at 95 km. Thus, a hybrid WDM/TDM PON with a hybrid amplifier improves the reach by 67 km with an increased number of users up to 256.