Time lens speeds up optical communication

Cornell University researchers have developed a method to accelerate optical communication with a ‘time-lens’. It can transmit compressed and combined data streams at a rate of 270Gbps.

Two Cornell University employees developed a time lens that enables a higher speed with which data can be sent over optical carriers. The invention by Cornell physicist Alexander Gaeta and Michal Lipson is energy efficient and can multiplex regular 10Gbps connections to a data stream of 270Gbps. Not only does the lens ensure faster optical communication: the technology also brings the arrival of optical computers closer.

Gaeta and Lipson based their work on research by Brian Kolner, who worked for HP when he made his prototype ‘time-lens’. His version, however, required an expensive crystal modulator that turned out to be anything but energy-efficient. Gaeta and Lipson’s new time lens works by encoding a signal into laser light using a modulator. This 10Gbps signal is fed to a silicon waveguide, where it interferes with laser light and breaks down into sub-frequencies.

Then the split light signals are fed to a second waveguide, where they interact again with the same laser light that caused them to split. This time, however, the signals are intertwined. However, their phase has changed at that point. In this way, traditional 10Gbps flows are compressed in time, resulting in effectively faster communication.

The multiplexing causes the signals to exit the Cornell chip at a rate of 270Gbps, with the only heat source being the laser that split the signal. In addition to the high transfer rate and low heat generation, the silicon lens offers a third advantage: integration with existing silicon components is easy, as it is an identical material.