Maintenance and Deployment of Fibre Infrastructure in the Access Domain for FTTH Networks

Abstract:
Current bandwidth limited copper access networks will be substituted stepwise by FTTH networks. Installation of a fibre based access network requires significant investments but in turn it guarantees to cope with the accelerating growth of bandwidth demand of the customers. At the same time operational costs (OPEX) must be minimised, therefore a passive optical network (PON) is rolled out from Central Offices (CO) to customers with no active components in the field. A further basic requirement for achieving minimum OPEX is the compliance of active and passive components with common standards and their interoperability, e.g. the fibre types installed in the buildings must be compatible to the fibre of the PON. Standardised GPON functions guarantee seamless interoperability and provide options for operators to choose GPON-ONT at customer sites independently of the CO based GPON-OLT. GPON supports remote monitoring of quality of service and fault detection, thus the majority of faults will be automatically detected in a minimum of time and at low operational expenditures. By implementation of proper filters in the CO, GPON and XG-PON systems can easily coexist on the same fibre network without mutual interference, supporting hitless network upgrades. Additionally, a 1625/1650 nm filter port enables in-service measurements with OTDR and insertion loss testers at the CO. The capability to distinguish adjacent events, closely spaced in terms of fibre length, by OTDR-measurements in a PON is investigated. This includes using the GPON-ONT for testing the network from the CO. Effective PON monitoring is thus achieved by a combination of GPON-system performance monitoring of TC- and optical layer functions and remote OTDR measurements in order to significantly reduce operational expenditures compared to traditional on-site support by service personnel.