Boonchuan Ng

A new fault-identification method using Access Control System in PON appliance

A new method is studied which can automatically identify faults between an optical splitter and the multiple optical network unit (ONU) on the customers side. This method employs an Access Control System (ACS) in the middle fiber plant, and inserted between the optical line terminal (OLT) and the ONU. The ACS is using OTDR basic source at 1625 nm wavelength from the central office (CO) in this fault identification method. The required characteristics and structural design method for the ACS are discussed. A prototype of the ACS is fabricated and which achieves the target characteristics and reliability. System evaluation experiments are carried out and the possibility of 100% fault identification is confirmed as a result of accuracy tests in the field.

Low cost method for testing, troubleshooting and monitoring of passive optical network - Towards the installation of Centralized Failure Troubleshooting System (CFTS)

This paper presents the simplest and fastest technique on testing and troubleshooting a passive optical network (PON) using handheld optical power meter and optical time domain reflectometer (OTDR). This provides a faster, simpler, and less complex way for installation testing, service activation testing, and network performance monitoring and troubleshooting a PON network without need of optical spectrum analyzer (OSA). The architecture is divided into 2 parts; electronic application injection and optical layer. Two units of handheld optical power meters is used as the injected wavelength and measurement meter for the triple-play (data, voice, and video) services. The whole network status line-to-line connection could be troubleshot with OTDR for further processing. Finally, we proposed the automatic monitoring network scanning to define the status of network by using our developed program by means of Smart Access Network Testing Analyzing and Database (SANTAD). A very simple set up and visual basic programming enable all status lines can be displayed and monitored onto one computer screen by means of Centralized Failure Troubleshooting System (CFTS).

Analysis software tool for optical access network: Smart Access Network _ Testing, Analyzing and Database (SANTAD)

This paper presents and experimentally demonstrates a MATLAB-based graphical user interface (GUI) namely Smart Access Network _ Testing, Analyzing and Database (SANTAD), which will be installed at central office (CO) for centralized monitoring the network system and troubleshooting any degradation or fault that occurs in passive optical network (PON) downwardly from CO towards customer residential locations. SANTAD is interfaced with a commercially available optical time domain reflectometer (OTDR) to accumulate every network testing result to be displayed on a single computer screen for further analyzing. The developed program will identify and present the parameters of each optical line such as the lines status, optical signal level, magnitude of decreasing, failure location, and other details as shown in the OTDRs screen.

The Faulty Optical Fiber Mechanism and Fault Localization Techniques in TDM-PON Network

In this paper, the mechanism of failure (breakdown) detection in an optical fiber line will be studied. The objectives of this paper are to understand in detail the mechanism of faulty fiber and previous recommended fault localization techniques for fiber-to-the-home (FTTH) access network. The detail failure analysis results, failure mechanism, and eliminating solution will be studied and presented. It was reported that any failure in FTTH is affected the triple-play services transmission. Conventionally, a fiber fault in FTTH can be located using optical time domain reflectometer (OTDR) upwardly from customer premises toward central office (CO). Technician is sent to the optical network terminal (ONT) or optical network unit (ONU) side to inject an OTDR pulse into the faulty fiber. This approach would require much time and effort. Moreover, OTDR can only display a measurement result of a line in a time. Therefore, it becomes a hindrance to detect failure of optical line with a large number of customer premises and large coverage area in the fiber plant by using an OTDR. Besides, it is difficult to detect a failure in optical line equipped with passive optical splitter by using a conventional OTDR in the CO downwardly from CO towards the customer premises, because the Rayleigh back-scattered (RBS) light from different branches overlap with each other in the OTDR trace and cannot be distinguished. To overcome these problems to achieve desired network survivability, we introduced a MATLAB-based graphical user interface (GUI) named Centralized Failure Detection System (CFDS), which is potentially used to increase efficiency and flexibility of FTTH, particularly in monitoring the optical signal flow and locating a fiber break downwardly from CO. To perform all the mentioned tasks, interfacing between the developed program with OTDR is required.