The reduction of cost of fiber-optic technologies makes this medium more attractive for resolving transmission issues in the access part of telecommunication networks. Fiber-optic technologies are needed in this part of the telecommunications network, because services that are delivered to end-users demand more and more bandwidth. Thus, there are currently two scenarios for the introduction of fiber-optic technologies to the access network: step by step, where the proportion of optical cables in relation to metal cables is increasing as time passes, and directly, where the optical fiber is taken directly to the user’s premises (for example, in fiber-to-the-premises [FTTP] networks). It might seem that the end-user’s needs could be satisfied by simple technological upgrading. However, the number and types of services that are transmitted per access line can be wide ranging. The mutual interaction between these services may derogate the quality of one or more services. Therefore, it is necessary in the access networks, in addition to providing sufficient bandwidth, to provide mechanisms to protect the quality of service (QoS). For this purpose, the second International Workshop on Fiber Optics in Access Network ( FOAN ) was held in October 2011. In addition to standard topics on the optical physical layer, the focus of FOAN 2011 was on QoS in the access networks. Like in 2010, the workshop was held within the International Congress of the Ultra Modern Telecommunications and Control Systems ( ICUMT ). ICUMT 2011 was held in

Telecommunications networks throughout the transmission system are adopting fiberoptic technologies, because they are the most profitable part of the telecommunications infrastructure. Over time, with significant price reduction, optical technologies began to spread to all aspects of telecommunications. Currently, tremendous growth is being witnessed in the number of services to endusers of telecommunications networks. With a large number of services, the needs of end-users for bandwidth are also rising. Therefore, there is a basic rule to replace, as much as possible, short copper wires with an increasing proportion of fiber-optic cable in the subscriber fixed line of telecommunications networks. Using fiber-optic technology, where until recently there was a copper twisted pair, has its own specifics. The First International Workshop on Fiber Optics in Access Networks (FOAN 2010) was held in Moscow in October 2010 with the aim of gathering researchers and engineers who will provide more details about implementation specifics. The workshop was held within the ICUMT 2010 (International Congress on Ultra Modern Control Systems). The ICUMT is an annual international congress providing an open forum for researchers, engineers, network planners, and service providers in telecommunications and control systems targeted on newly emerging algorithms, systems, standards, services, and applications. The ICUMT is positioned as a premier international annual congress for the presentation of original and fundamental research and engineering results. The aim of the ICUMT is to bring together Russian and international players in telecommunications and control systems. The workshop was divided into two sessions, the first, called “Technology and Services,” aimed at showing the networks, services, and technologies in general. The second, entitled “System Performance and Optical Devices,” showed the recent events in this field. For this workshop, 15 articles were submitted; after the review process, 9 were accepted and presented, and 5 were selected for this special issue. The selected articles cover topics from a backbone network to top services, such as 3D (three dimensions) video.

The paper presents a method for the attenuation measurement of the optical path from ONU to OLT in GPON network. Optical power meter is connected to the fiber section via splitter in central office receiving optical signal from all ONU's. Optical power difference is measured in upstream signal with desired ONU in “on” or “off” state. The difference has a linear relationship with user's bandwidth. Finally paper describes an experimental setup for confirmation of proposal, the results differ by 2,5% from theoretically calculated. The system will improve the service reliability and reduce the maintenance cost.