21285 - SCTE Broadband Dec2021 COMPLETE v1

50 Vol. 43 No. 4 - November 2021 Issue technical with limited power budget. Bend resistance allows the use of smaller loop guides upon installation and reduces the bend radius of splice trays. As a result, connectivity devices become smaller, saving even more valuable space. And in dynamic network environments, bend resistance extends the expected network lifetime by improving repair resilience, too. Utilising wavelength division multiplexing (WDM) optics in PON and wireless networks drives the need for bend-insensitive fibres to become part of FTTX and 5G mobile networks. Fibre optic networks are a long-term investment and the solutions used to build them must be considered carefully. G.657 cabling systems’ broad-spectrum transmission, small diameter and ‘pay-as-you-grow’ potential is what makes them the ideal, future-fit solution. With their preservation of system power budgets – even when installed by less-practiced technicians – the use of cable solutions with bend-insensitive fibres is an opportunity for significant OPEX savings. The above graphic demonstrates the attenuations which occur in an 18km link over time, beginning on day one of access network deployment, and after accidental bends occur during the life-time of the network. The link consists of only one 1:8 splitter (9dB loss) and 18km of cable. Insertion loss of splices, patchcords and connectors, as well as safety margins are not included. Considering a PON system with 28dB link budget, the cable’s maximum allocated budget loss is 19dB. The solid black line in the diagram represents the attenuation of the 18km span at day one of the deployment. The attenuation of the cable is below 8dB from 1250-1650nm. As more access points are added to the system, it’s likely that accidental bends may occur. The diagram demonstrates cable attenuation when just five 7.5mm radius accidental bends occur over the 18km span. The dotted blue line represents a cable with G.652.D fibres. It will experience a significant increase of attenuation and the total loss of the link exceeds the 19dB budget allocated to the cable for wavelengths longer than 1490nm. The dotted orange line is a cable with G.657.A1 and passes the allocated budget for wavelengths longer than 1580nm. The solid blue line shows the attenuation of the cable with G.657.A2 fibres is well below the 19dB budget allocated to the link throughout the 1250-1650nm wavelength range. Therefore, the network with this cable can help operators to reduce repairs and future-proof the network. Access network system evolution Advanced broadband wireless and FTTX networks are considered essential infrastructure to support economic growth. Deployments of FTTX and mobile networks have consumed more than hundreds of millions of fibre km per year to support the bandwidth demand of end users. Having deployed 1 Gigabit PONs (EPON and GPON), operators moved to a higher speed of 10 Gigabits in 2015: 10 Gigabit EPON (10G-EPON) and 10 Gigabit (symmetrical) PON, or XG(S)-PON. XG(S)-PON already used a broader spectrum