Today, OLTs are connected to metro ethernet networks using 10G interfaces. if it is necessary more capacity to configure a LAG what allows to have a bandwidth of 2x10G - 4x10G. The problem is that the OLT controllers do not support these speeds or an expensive upgrade is needed. The arrival of the 5G and the foreseeable increase in associated traffic, it raises the use of 25G interfaces in OLTs connections and 5G telephony station aggregating equipment. In this sense the 1x25G is a simplification of the 100G optical formed by lambdas of 4x25G type LR4. In this sense, I believe that POET is right to position itself in this type of optics.