A TEO-Based Algorithm to detect events over OTDR Measurements in FTTH PON Networks Lima, Gerson F. M; Lamounier, Edgard; Cardoso, Alexandre; Peretta, Igor Federal University of Uberlandia MG- Brazil Barcelos,Sergio; Muramoto, Willian; Rigon,Elso; FiberWork Optical Communications Campinas-Brazil Abstract— The FTTH business needs new network maintenance technologies that can, economically and effectively, cope with the massive FTTH fiber plants that are yet to come. Based on the Teager Energy Operator (TEO), we have developed a method for testing and evaluating FTTH networks from the Central Office, which allows the identification of event failures in the optical branches after the PON splitter. Keywords: OTDR signal Optimization, FTTH, PON networks, Teager Energy Operator (TEO) I. INTRODUCTION By allowing data communication over twisted copper pairs, the xDSL technology has made data access to the homes possible, using the already installed telephony lines. This was an important historic achievement as it allowed society to feel the taste of home broadband access while providing some additional business life to those long-lived telephony lines. On the other hand, the ever growing demand for online services and internet applications creates a sustainable market for larger and larger bandwidth access networks. The twisted pair telephony lines cannot cope with this, so they have become a marginal access network medium. Fostered by the long distance and metropolitan telecommunication markets, the optical fiber communication technology came down in price considerably over the last 30 years. So, by adding economic feasibility, technical superiority and market demand, one would not need a crystal ball to say that optical fibers would eventually replace the twisted pairs in the home access networks. And the time for Fiber To The Home (FFTH) has then arrived. Passive Optical Networking (PON) is an economically viable technology to provide ultra-broadband FTTH access networks. This viability is made possible by the shared network infrastructure model employed. Sharing the most expensive element of network infrastructure builds, civil engineering costs, amongst multiple subscribers, enable the optical fiber to economically reach the homes. The non-shared infrastructure model, in which a dedicated fiber runs from the central office to each home, multiplies the engineering costs, instead of sharing it. It also demands more active terminals, more room space in the central offices, more energy supply and increases failure risk. Therefore, the PON model has become the option of choice for providing Fiber To The Home (FTTH). The copper pair networks will gradually be replaced by a FTTH plant. An enormous number of homes will then be served by optical fibers. This poses a great level of worry: how to fast, effectively, efficiently and economically test and repair the massive FTTH network plants of the future. A variety of Optical Time Domain Reflectometry (OTDR) testing methods have been designed for the verification and troubleshooting of PON’s, such as testing all points from the optical network terminal (ONT) to the central office (CO), testing the feeder part of the network from the CO, and, in some cases, simply not testing at all [1]. OTDR methods provide reliable results and, since it is a single-ended method, it significantly reduces staff time. The cost of the OTDR instrument and the required skill level of the user are usually perceived as its drawbacks. Reflectometric signals are processed by software using different methodologies to recognize events, failures and degradations in the optical fiber. This matter has long been dominated for point-to-point fiber networks [2]. For FTTH PON architectures, however, several new challenges arise when testing through optical splitters [3]. This is overcome by either testing from the ONT side or testing up to the splitter position only. The former is a non-economical solution as it would require an enormous amount of testing instruments and well trained field technicians [4]. The latter can only see the feeder part of the network, i.e., from the CO up to the splitter position, which is usually the network portion less prone to failures. After the splitter, the OTDR measurement brings little information because the Rayleigh scattering is strongly attenuated by the double-passage through the splitter, because the 64 backscattered signals from the PON branches superimpose at the OTDR receiver, making impossible to recognize events from single PON branches, and because traditional OTDR technology has low dynamic range when used with short OTDR pulses, which is a requirement for PON measurements. Moreover, traditional OTDR technology relies on a mathematical method called Least Squares Approximation, LSA, for event analysis. The performance of this method, which is already limited for analyzing point-to-point networks, is fully inadequate for PON networking OTDR measurement and analysis. Teager Energy Operator (TEO) methods have proven effective for a variety of audio signal processing [5, 6] and for the analysis of digitalized images used for text segmentation [7]. In this work, we have used the Teager Energy Operator to develop a method, which we have named TEO-OTDR, for pos-