A large part of our impact is possible thanks to our partnership approach. For example ours Echo and Bifrost Cables rely on local consortium partners, including Keppel, cable, and XL Axiata. We’re working together to increase total transpacific capacity by 70 percent. Scaling the subsea infrastructure is an important part of our overall approach to building global connectivity systems that will help connect many more people to the internet in the years to come.
Use of robotics to deliver fiber optics faster
While submarine cables are part of the backbone of the global internet, the next step is to deliver bandwidth to communities once a submarine cable hits shore. However, current methods of providing fiber optics are labor intensive and costly. As a result, the fiber installation has been a bottleneck in delivering more fiber and creating the kind of abundance necessary to allow unrestricted internet access for everyone regardless of income level.
With each strand of fiber costing pennies per meter while the fiber installation costs anywhere from ten to one hundred dollars per meter, we wondered if we could cut the cost of installing fiber optic cable.
“To answer that question, we first thought of medium-voltage lines, the familiar three wires you see on top of a power pole,” says Karthik Yogeeswaran, a wireless systems engineer at Facebook. “In most parts of the world, medium voltage lines run through almost every street. If we could find a way to add fiber to these power lines, we would have a solution that could be used around the world. “
Our solution is Bombyx, a robot for delivering air fibers This makes the provision of fiber optics faster and cheaper. Latin for Silkworm, Bombyx is our attempt to make the biggest drop in the cost of terrestrial fiber deployment by combining innovations in robotics and fiber optic cable design to increase the amount of terrestrial fiber on land – without the cost of digging fiber underground.
Since we started working on Bombyx, we have reduced the weight of the robot by 4.5 kg, the time it takes Bombyx to cross a power line from 17 minutes to under 4 minutes and improved the stabilization system that allows the robot to run over enables obstacle.
We are now also working on changing the robot from semi-autonomous to fully autonomous operation when it crosses an obstacle. In our current semi-autonomous system, operators monitor and control the robot’s movements when crossing obstacles. If we move to full autonomy, technicians can simply load Bombyx onto the line and then allow the robot to draw a course past obstacles and navigate itself along the line.
Our work on Bombyx was inspired by spiral fiber optic wrapping Techniques that were pioneered in the 1980s, but these methods required disconnection of power to customers during installation. We realized that we would also need this winder to overcome obstacles in their path without human assistance, to install fibers without cutting off homes and businesses.
First, however, we faced some pressing challenges in fiber optic cable design. For example, if you are wrapping fiber optic around a power line, you will need to carry the entire length of fiber that you want to provide. One kilometer of normal air fiber weighs approx. 113 kg, even the special cable of the older spiral winding systems weighed approx. 36 kg. Combined with a robot to deploy the fiber, it would be too heavy for power lines, which are typically very thin and of limited weight. Since medium voltage conductors also get very hot, we needed a fiber optic cable that could withstand possible stretching and melting.
To address these design challenges, we used a few strategies. First we used Kevlar braid to make the cable strong while keeping it small and flexible. Next, we took on the challenge of size and weight and reduced the number of fibers from 96 to 24. Thanks to newer technologies, a single fiber can supply up to 1,000 households, so 24 fibers could supply all homes and businesses that each power line entry goes into. Finally, we worked with leading material suppliers to develop a coating for the fiber to help it withstand the high temperatures found in power lines and possible damage from high voltage arcing.
Designing a robot that crawls along power lines and overcomes obstacles was our next big challenge. Bombyx uses advanced movement techniques to balance itself and turn itself over as it moves over obstacles and wraps fibers around power lines.
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