2008 International Conference on Electronic Design December 1-3, 2008, Penang, Malaysia A New Approach for Identifying Fiber Fault and Detecting Failure Location Mohammad Syuhaimi Ab-Rahman, Ng Boon Chuan, Aswir Premadi, Kasmiran Jumari Computer and Network Security Research Group Department of Electrical, Electronic and Systems Engineering Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia 43600 UKM Bangi, Selangor, Malaysia Email: syuhaimi@vlsi.eng.ukm.my Abstract Optical time domain reflectometer (OTDR) is used to measure fiber attenuation and loss as well as locate connection, splice, crack, bend, and breakdown along an optical fiber. This paper proposed and demonstrated a MATLAB-based graphical user interface (GUI) named as Centralized Failure Detection System (CFDS) that able to measure the optical signal level, attenuation, loss and also locate the break point in faulty fiber for multi fibers in a time. CFDS is interfaced with the OTDR to accumulate every measurement result to be displayed on a single computer screen for further analysis. CFDS will identify and present the parameters of optical fiber such as the fiber's status either in working or non-working condition (occur breakdown or failure in a faulty fiber), magnitude of decreasing as well as the location, failure location and other details as shown in the OTDR's screen. Index Terms - OTDR, Centralized Failure Detection System (CFDS), failure location, opticalfiber 1. INTRODUCTION OTDR can locate defects and problems in optical fiber. A basic OTDR includes a laser diode source and a photo detector. A high intensity optical pulse is launched into an optical fiber and a high speed photo detector recorded and graphically displays the observed reflection in the screen. The user can observe losses due to splice, break, crack, connector, and other attenuation along a fiber which can extend for over 100 km by looking at the visual representation on the OTDR's screen [1]. OTDR is the most costly among 978-1-4244-2315-6/08/$25.00 ©2008 IEEE. the optical fiber test equipments but it is most frequently used for characterizing a long haul communication link. However, OTDR testing is the best method for determining the exact location of broken optical fibers in an installed optical fiber cable when the cable jacket is not visibly damaged [2]. Conventionally, the measurement results can be transferred into computer for performing more OTDR trace post-processing functions by using computer- based OTDR emulation software. Unfortunately the emulation software is same as the OTDR which can only able to display a single measurement result in a time and also time consuming and cost misspend. Therefore, it becomes a hindrance to detect the break point of faulty fiber in the optical fiber communication links especially in fiber-to-the-home (FTTH) with point-to-multipoint (P2MP) connectivity or passive optical network (PON) architecture with a large number of subscribers and large coverage area. This makes the troubleshooting work become very complex and leads to increase the operation cost. 2. OTDR CONCEPT OF DETECTION An OTDR trace is beginning with an initial input pulse. It can be having several common characteristics. Time period for the OTDR trace results from Rayleigh back scattering (RBS) as the laser source travels along the fiber section of optical fiber are interrupted by an abrupt shifts named as point defects. A point defect is a temporary or permanent local deviation of the OTDR signal either in upward or downward direction. Point defect caused by a connection, splice or failure along an optical fiber. The output pulse is indicated as end of an optical fiber from Fresnel reflection occurring at each fiber