Type of Document	Dissertation
Author	Akanbi, Oladeji Bamidele
Author's Email Address	djakanbi@ece.gatech.edu
URN	etd-11082006-141534
Title	Bi-directional Dense Wavelength Division Multiplexed Systems for Broadband Access Networks
Degree	Doctor of Philosophy
Department	Electrical and Computer Engineering
Advisory Committee	Advisor Name Title Gee-Kung Chang Committee Chair Constantine Dovrolis Committee Member Ian Akyildiz Committee Member John Buck Committee Member Stephen Ralph Committee Member
Keywords	broadband access wavelength division multiplexing optical networks
Date of Defense	2006-11-16
Availability	unrestricted
Abstract Dense wavelength division multiplexing (DWDM) is becoming the technology of choice for meeting the increasing bandwidth demands in optical networks. DWDM has been used to increase the capacity of long-haul optical transport systems. Efforts are being made to move DWDM into the broadband access network serving residential and business subscribers. First, a new centralized DWDM PON scheme is demonstrated for bi-directional upstream and downstream transmissions. The proposed DWDM PON scheme is implemented using optical carrier suppression and separation (OCSS) technology to generate a wavelength pair from a single laser source at the central office. This method enables the co-location of both upstream and downstream DWDM transmitters in the central office. In addition, the complexity, cost, and maintenance of the optical network unit are reduced by enabling wavelength independent operation. Second, a new multistage architecture is proposed for the delivery of information to groups of subscribers located at different distances from the central office. A 25 GHz DWDM comb is generated using OCSS technology, and error-free transmission of four 10 Gbps channels is demonstrated. Finally, a new wide area access network with bi-directional DWDM amplification using semiconductor optical amplifiers (SOAs) is demonstrated. The detrimental effect of SOA crosstalk resulting from cross gain modulation can be suppressed using a constant intensity modulation format such as differential phase shift keying (DPSK). The feasibiity of bi-directional DPSK transmission of 16 interleaved DWDM channels using an in-line SOA has been studied experimentally. In addition, the reduction of bi-directional SOA reflections has been realized by optimizing the SOA bias current and facet reflectivities.
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