Thermal design of an optical network unit (ONU) to be implemented into an outdoor enclosure

The ONU is the transmission system between the subscriber and the network-side transmission facility, i.e. the central distribution node (CDN). In the ONU, the subscribers are connected via service units (SU). These service units provide the subscriber-specific interfaces. By performing a preliminary thermal analysis during the concept phase, it was possible to determine the boundary conditions to install a shelf into an outdoor enclosure which had already been developed. Initial simulation models were derived. During the analysis phase it became clear that the transformer in the AC/DC power supply would be excessively heated. Therefore further variants were simulated. Measured data were obtained from a prototype and compared with the simulation data