Network monitoring for passively split optical fibre networks

Optical fibre networks offer an attractive solution to network operators for the distribution of video and other integrated broadband services to potential customers. One possible fibre network architecture for broadband distribution is the passive optical network (PON). It consists of a number of cascaded passive optical power splitters, originating from a single optical fibre, and it may be terminated at the customer's premises with optical nodes, wherein each node may contain a number of optical connectors and other optical components. The maintenance of such passively split networks presents a new set of challenges to service providers, as due to the star topology, the various branches of the network are likely be equidistant from the transmitter such that they cannot be sensibly probed and addressed from the head-end via a conventional maintenance instrument such as the optical time domain reflectometer. A frequency domain reflectometry technique is employed for characterising and monitoring the passively split optical fibre network, wherein, the reflectometer (OFDR) continuously interrogates the fibre network by reporting upon the status of reflective nodes distributed throughout the PON.