A novel RoF-based optical switching architecture using position-tracking algorithm in passive optical networks

Abstract

The explosive growth of the Internet traffic for subscribers has fueled the development of high-speed transmission systems. Optical transmission systems give some opportunities through the infinite bandwidth, high-speed transmission and etc. Also, optical transmission systems are employed in the access network. Especially, a passive optical networks (PON) is important system in the optical access network. In passive optical networks, a group of optical network units (ONUs) is connected to the central office (CO) by a series of optical links. The communication links interfacing ONUs are dedicated and form the distribution networks. The communication link of the CO side is instead shared by all the ONUs of the network and is called feeder network. Between feeder and distribution network a structure composed by one or more remote nodes (RNs) and entirely implemented by passive optical devices performs separation of downstream optical channels as well as multiplexing of upstream optical channels in a transparent way. Compared with networks with active components, PONs offer several meaninful advantages: low cost, high reliability, no need for maintenance. The time-division multiplexed PON (TDM-PON) is the best known solution for FTTH: the optical carrier is shared by means of splitter among all the subscribers. It can be implemented with low cost sources and components, but the number of users is limited by the splitter attenuation and by the working bit-rate of the transceivers of the CO and ONU. In the other hand, a convergence system between wireline network and wireless network is a hot issue recently. A radio over fiber (RoF) is one of convergence issues. RoF is an analog optical link transmitting modulated RF signals. It serves to transmit the RF signals downand uplink, i.e. to and from central stations (CS) to base stations (BS) called also radio ports. RF modulation is in most cases digital, in any usual form such as PSK, QAM, TCM, etc. It is not inconc...