Using a single laser, scientists were able to encode data and transmit it over 50 km of single-node fiber using “325 optical frequencies within a narrow spectral band of laser wavelengths.” The single laser was capable of handling 26 terabits of information per second in an energy efficient manner, which is equivalent to the amount of data used by 400 million phone calls.
The technique used to encode and decode the optical data is called orthogonal frequency-division multiplexing (OFDM). It is a modulation technology that can be applied to both optical and electrical based transmission methods. The data is broken down into numerous parallel streams of data (using mathematics) that greatly increases the transmission speed and amount of bandwidth available. While electrical/copper based systems are not able to transmit 26 terabits of information using OFDM, optical systems are able encode the amount of data in their experiments without speed restrictions and while using “negligible energy.” Dr. Leuthold stated “we had to come up with a technique that can process data about one million times faster than what is common in the mobile communications world.” Further, his stated that his experiment shows that optical technology still has room for transmission speed improvement, and increases in bit-rate do not necessarily result in higher energy usage.
The important aspect of Dr. Leuthold’s research lies in the energy efficiency inherent in reducing the amount of lasers and fiber nodes required to transmit 26 terabits per second of data. Using simple optical technologies, they are able to greatly increase the amount of bandwidth in a single fiber line. Japanese researchers have been able to achieve 109 terabits per second download speeds; however, they had to use multiple lasers to achieve the speeds. Dr. Leuthold iterated that “it’s the fact that it’s one laser,” as being the important results of his research.
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