Issue link: https://www.e-digitaleditions.com/i/1327492
January/February/March 2021 I 15 ITU-T G.671 standard (optical branching component), which is slightly higher than standard splitter insertion loss due to the modal adapting function implemented (+1 dB maximum). This technique allows for SMF/MMF connections and, therefore, the implementation of POL over a multimode infrastructure, regardless of MMF type: 50/125µm or 62.5/125µm (OM1, OM2, OM3, OM4, and OM5). CASE STUDY: RETROFITTING AN OLD MMF CABLING INFRASTRUCTURE FOR POL Before delving into an actual case study, it is important to note that several worldwide POL deployments on MMF have been completed. From these deployments, the following results of this technological innovation include: • Successful implementation of POL on existing MMF cabling infrastructure. • The singlemode to multimode splitter allows enterprise customers to leverage existing multimode fiber cabling inside their building and readily supports 10 Gb/s speeds when and where needed. • Successful transmission of GPON traffic over MMF. • Verification of the coexistence of the GPON and XG-PON systems in terms of traffic. Regarding their needs and goals, CEREMA decision makers wanted POL architectures for their new sites under construction. However, as a state nonprofit organization committed to sustainability, CEREMA could not start from scratch for existing sites. It needed an environ- mentally friendly solution and one that would be feasible on a fixed budget. CEREMA wanted to speed up its LAN performance with minimal waste and within its budget. Furthermore, three years earlier, CEREMA had rewired part of its backbone and distribution cabling infrastructure with OM3 MMF at its Aix-en-Provence site. Primary objectives were to minimize disruption and to avoid a SMF installation when renovating the LAN to a POL at this site. An existing 200 m long MMF cable between the main distribution frame and the intermediate distribution frame was used to meet CEREMA's objectives (Figure 8). FIGURE 8: An existing MMF cable was used to minimize disruption and avoid a costly SMF installation for the Aix-en-Provence site. The huge amount of MMF, comprising the existing campus backbone and distribution fiber links, is incompatible with GPON equipment. The CEREMA Case Study CEREMA is a French scientific and technical resource center focused on sustainable development, town planning, and trans- portation. A subsidiary of France's sustainable development ministry, CEREMA has 3,000 employees across several campuses. Focused on sustainable development projects through- out France, CEREMA needed access to large file formats and the ability to share them among multiple locations. For CEREMA, slow network speeds would hamper productivity.