CableLabs high on coherent optics for short-haul access networks

CableLabs HQ
CableLabs “distinguished technologist” Alberto Campos makes the case for using coherent optics technology for short-haul access networks.

CableLabs has come out strongly in favor of using coherent optics technology for short-haul access networks. 

“Today, the most constrained part of the network, and the most costly to upgrade, is the fiber infrastructure between the headend and the fiber node, to the wireless cell radio or to large business customers,” said CableLabs “distinguished technologist” Alberto Campos, blogging for CableLabs. “Avoiding costly fiber re-trenching requires a fundamentally new approach to this part of the network. This is where coherent technology provides an opportunity.”

With fiber being used for business services, cell backhaul, node splits and fiber deep architectures, many cable plants have only two primary fibers that are feeding the fiber node and which remain available for access transport.

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Capacity shortages, Campos argues, are only going to get worse. “This fiber shortage problem will only intensify as fiber demand for business services and wireless backhaul increases. Assuming that costly fiber re-trenching from hub to original fiber node is to be avoided, a different solution must be found to provide the required capacity. This is where coherent technology provides an opportunity!” he said.

“If you are familiar with coherent optics, then you are aware that the technology has been used in long-haul fiber optic networks for decades,” Campos added. “CableLabs has adapted that technology for use in short-haul access networks, and simplified it to reduce the cost,” Campos said. “And it has much higher capacity for future growth than the analog optics that are used in many of today’s HFC networks—possibly more than 1,000 times more capacity! We have already demonstrated 50 times more capacity than analog optics can achieve today by using coherent optics on 80 kilometers of fiber, and more improvements are on the way.”

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