Laser-Radio Wireless Links Upgrade the Internet

As reported by MIT Technology Review: The rise of Wi-Fi and cellular data services made Internet access more convenient and ubiquitous. Now some of the high-speed backhaul data that powers Internet services looks set to go wireless, too.

Technology that uses parallel radio and laser links to move data through the air at high speeds, in wireless hops of up to 10 kilometers at a time, is in trials with three of the largest U.S. Internet carriers. It is also being rolled out by one telecommunications provider in Mexico, and is helping build out the Internet infrastructure of Nigeria, a country that was connected to a new high-capacity submarine cable from Europe last year.

AOptix, the company behind the technology, pitches it as a cheaper and more practical alternative to laying new fiber optic cables. Efforts to dig trenches to install fiber in urban areas face significant bureaucratic and physical challenges.

Meanwhile, many rural areas and developing countries lack the infrastructure needed to support fiber, says Chandra Pusarla, senior vice president of products and technology at AOptix. He says a faster way to install new capacity is to use his company’s wireless transmission towers to move data at two gigabits per second.

Pusarla says the service is particularly attractive to wireless carriers, whose customers have growing appetites for mobile data. Many U.S. providers are currently scrambling to install fiber to replace the copper cables that still link up around half of all cellular towers, he says, but progress has been slow and costly. In the suburbs of New York City, the cost of installing a single kilometer of new fiber can be $800,000, says Pusarla.

AOptix technology takes the form of a box roughly the size of a coffee table with an infrared laser peering out of a small window on the front, and a directional millimeter wave radio beside it. The two technologies form a wireless link with an identical box up to 10 kilometers away. A series of such connections can be daisy-chained together to make a link of any length.

AOptix teamed up the laser and radio links to compensate for weaknesses with either technology used alone. Laser beams are blocked by fog, while millimeter wave radio signals are absorbed by rain. Routing data over both simultaneously provides redundancy that allows an AOptix link to guarantee a rate of two gigabits per second with only five minutes or less downtime in a year, whatever the weather conditions, says Pusarla.

A typical fiber connection might be 10 or more times faster than that, due to the limitations of the radio frequency link. But AOptix says the convenience of its technology makes up for that, and it could be increased to four gigabits or more in the future.

The radio and laser equipment inside an AOptix device move automatically to compensate for the swaying of a cell tower caused by wind. AOptix originally developed its laser technology for the Pentagon, designing systems that actively steer laser beams to keep data moving between ground stations, drones, and fighter jets. 

Pursala declined to identify the three U.S. carriers that have been testing AOptix’s technology over the past year or so, or its Nigerian customer.

Other early customers are being more open. The Mexican telecommunications company Car-sa recently switched on the first of several links it plans to use to link up cellular towers and provide Internet to corporate customers. And before the end of the year, Anova Technologies, a networking company that specializes in the financial industry, will use AOptix technology in New Jersey to shave nanoseconds off the time it takes data to travel between the computers of Nasdaq Stock Market and the New York Stock Exchange.