Investigating Maximum Fiber Link Length with SEDFA

Abstract: Fiber optic is one of the most rapidly growing technologies used these days for high bandwidth networks. This rapid growth in this area is resulting in production of cheaper and low power equipment. The objective of this study is to investigate the limitations of an optical network while using low cost and low power equipment. This study presents the analysis regarding the use of standard low cost fiber equipment to reach distances above 250 km for 1 Gbps networks and try to achieve more than 100 km for 10 Gbps fiber networks. The transceivers used for this study for 1 Gbps networks are rated to reach 150 km and for 10 Gbps the transceivers are made for 40 km. An EDFA (Erbium Doped Fiber Amplifier) is used to overcome the problems of low power. This study also presents an investigation regarding the placement of EDFA along the 1 Gbps and 10 Gbps links. This study is aimed at the rural areas of Somalia where power grids are not available in most of the region. Hence the tests have been performed to consider the use of solar power to run the amplifier. The results show that, by using a SFP transceiver built for 150 km and by the use of only one EDFA it is possible to achieve distances of maximum 310 km for 1 Gbps networks. This is possible due the use of an in-line amplifier placed after 150 km. The distance is limited to 310 km only because of the power limitation. For the 10 Gbps fiber link with XFP transceivers rated for 40 km, without use of amplifier, transmission was possible up to 75 km. After using an EDFA at 75 km, a distance of 125 km was achieved, but beyond that the dispersion was a limiting factor for the system. With the use of a dispersion compensating fiber unit, transmission was possible to a distance of 150 km. As the EDFA consumes very little power, approximately 1 W, the use of a solar panel to power the EDFA is a promising solution. According to the results even only four hours of effective sunshine is more than enough to charge the battery to run the low power amplifier. Even with multiple cloudy days the battery voltage was enough to power the EDFA.