Considerations and recommendations for in-service out-of-band testing on live FTTH networks

In this article, the authors present a detailed description of the causes of fiber-to-the-home network outages at the customer point, as well as the best practices for troubleshooting in-service passive optical networks. In addition, the two main fiber-to-the-home video technology trends (RF analog wavelength overlay or digital Internet protocol television using the same wavelength as high-speed data Internet) is reviewed and their repercussions on the network architecture is analyzed. The article also discusses the basic concepts of filtered power meter testing, as well as the limitations of using standard optical time-domain reflectometers in fiber-to-the-home networks (due to interference between the unit and the traffic). This analysis leads to the proposal of a testing methodology that uses an out-of-band filtered optical time-domain reflectometer and considers important isolation requirements for this unit. As the proposed methodology poses a challenge regarding test wavelengths, this aspect is also examined.