Optical encryption at 100Gbits/s now possible

Researchers have created an optical network component that they say can encrypt data travelling at 100Gbits/s, far outpacing current electronic encryption technologies.

The component, a passive optical coder that can be programmed remotely to change the encryption key, could allow carriers and large enterprises to secure all the data that travels over a high-speed WAN connection, according to Shahab Etemad, chief scientist director in the Advanced Technology Solutions division of Telcordia.

The company, which traces its roots back to the Bellcore research operation for US carriers, is looking for manufacturing partners to commercialise the technology as soon as two to three years from now.

Large enterprises are making increasing use of WDM (wave-division multiplexing), in which a beam of light can be divided into different colours, or wavelengths, with a different stream of data being sent over each one as pulses of light. WDM is more efficient than sending electrons over wires, and it offers speeds as high as 40Gbits/s per wavelength, with 100Gbits/s on the way. Companies typically lease a wavelength from a carrier that owns the fibre.

That wavelength becomes the physical medium for a high-bandwidth connection that can link one data centre to another, or to a backup facility, over a long distance.

But encryption still is typically done electronically, at a top speed of about 10Gbits/s, Telcordia's Etemad said. Without the high-speed optical encryption, enterprises that wanted to carry 100Gbits/s of traffic couldn't take advantage of the efficiency of putting it all on one wavelength. They would need 10 wavelengths, each carrying just 10Gbits/s and using its own electronic encryption system, he said. In addition to leasing more wavelengths, they would have to manage 10 different encryption keys.

Telcordia's optical coder is a component about the size of a US dime (17mm across) that alters the frequency of the light pulses going onto the network, Etemad said. The light pulses travelling across a fibre normally indicate a "one" with a light pulse and a "zero" with no pulse, but with the frequency altered by the coder, someone who tapped into the fibre couldn't see any of those pulses, Etemad said.

At the other end of the network, another coder alters the frequency back again to decrypt the data. An IT administrator can reprogram each coder - physically reconfigure it - by passing a current through it using a local or remote command.

Although the optical encryption works differently, it could be made as strong as typical electronic encryption systems, according to Etemad. The coder has successfully encrypted and decrypted traffic going over a 40Gbits/s connection that was 400 kilometres (248 miles) long, and has been demonstrated at 100Gbits/s in the lab, he said.

Telcordia announced the results in a peer-reviewed paper for a conference last year, but said for the first time on Monday that it will seek to commercialise the technology.