Limiting the number of homes on each segment of the return system increases the available bandwidth per home and limits the amount of ingress the return system must handle. A direct connection exists between multiple fibers from either the headend or a hub to each optical node. The optical node is the deepest point in the network at which segmentation can be achieved relatively easily. Furthermore, isolating the node s ports makes it possible to segment the service area. This allows placement of unique information on each port, segmenting the network even further.
Segmentation creates a network with many dedicated return links.
Finding an efficient and cost-effective architecture to transmit the information on the multitude of return links presents a challenge. The simplest technology for transmitting multiple returns is to dedicate a separate return transmitter, return receiver and fiber for each. FP lasers are the cheapest, but have the poorest performance and significant operational limitations. First, the thermal stability of FP lasers is poor. In particular, the noise level of these lasers will vary greatly with temperature.